approximately 300 miles from here. We are 150 miles north. We are also
180 miles west. We have temperatures up there too that we have to figure
on. The temperature in most years gets to minus 20 and the coldest we
ever had was minus 42, but that was only for an hour, but temperature is
only one factor. An old professor of the University of Iowa, regarded
wind as more important than temperature. The more I see of wind killing,
the more I believe he is right. Wind is more important than temperature.
If you have your trees surrounded, you don't get wind injury. The trees
I am reporting on were planted from 1920 to 1930. Some of them now are
16 to 18 inches in diameter and 30 feet high and the varieties are such
as we got from Mr. Wilkinson. Indiana, Busseron, and one other which Mr.
White--he is a wholesale druggist interested in horticulture--selected
and he knows the nut trees probably better than any other one man. He
kept in contact with these river rats and they would always bring
anything to him they thought was of interest. We have a bunch of
seedling trees about the same age and size which never bloom at all and
of course they are ready for cutting out. I don't know why there would
be a number of seedling trees that would never bloom.
DR. CRANE: In extensive breeding work, Mr. Clarence A. Reed started in
at Albany, Georgia, with 4,000 seedlings and out of 4,000 about half
that many came into production and bore fruit enough so we could tell
what the fruit was like in about 15 years. The other half just never did
bear. Those trees had grown and made large trees and in a lot of cases
they carried large leaves but there was no way we could predict anything
about fruiting. It was discouraging for that reason. We quit, in our
breeding work, growing the seedlings beyond one year. We make our
crosses now and grow them one year in the nursery. We plant nuts at
harvest and grow them until they form leaf buds and graft from the
seedlings on old trees cut back. We can save anywhere from one to three,
four, or five years. There are a great per cent that will not bear.
MR. MAGILL: In Iowa, out there, what varieties are making good?
MR. SNYDER: There aren't any. As nut producers they aren't worth
anything. Why not plant the hicans? They ripen better but don't bear.
The hicans make one of the prettiest trees but they don't bear.
We make no plans for pecans unless we have a season with no freezing
until the middle of November. So that is where the pecans are that far
north, except as shade trees.
MR. H. W. GUENGERICH: I feel that I am out of my territory in talking
about nut growing to this Association, but I have had a few things
forced on my attention that may be of interest.
When I first joined Stark Brothers Nursery, Paul Stark asked me to look
into the possibilities of locating a pecan variety that would be
satisfactory north of the southern pecan belt. I talked to our Missouri
extension horticulturist, Bill Martin, and he informed me that a lot of
pecans are being grown around Brunswick, Missouri, on the Missouri
River. The Missouri flows northeast from Kansas City for about 75 miles
and then swings toward the south again. Brunswick is located at the
northernmost point on the river, between Kansas City and St. Louis. It
is about 150 miles west of Louisiana, and in general the weather becomes
more severe as you travel West. So pecans that thrive and mature at
Brunswick are pretty rugged.
I went over to Brunswick to see a friend who introduced me to some pecan
growers. One of these men has an interesting story and I wish he were
here. I tried to bring him along but he could not get away from his
farming operations. He operates several hundred acres of farm land in
the Missouri River bottoms and his house stands in a grove of native
pecans. When he went into his house he pointed to a hook on the door
post where he tied his boat the previous spring when he moved his family
out because of high water. That year, 1947, all his grain crops were
destroyed by the flood but that fall he harvested 50,000 lbs. of pecans.
They sold for 25¢ a pound and the total expense was for picking them,
off the ground. In a year like that, $12,000.00 would come in handy. It
rained again in Kansas this year and I called him and asked about the
flood. He said he had a couple of inches of land that wasn't covered
with water, but he expects to gather 40,000 lbs. of pecans this fall.
That is interesting because there are thousands of acres in the middle
west where crops have been destroyed by floods. Yet here is a crop that
grows on native trees with very little care, that will pay off despite
high water.
I asked my friend what effect the high water would have on the pecan
foliage and he replied that the leaves would fall, but that the trees
will produce new leaves and the nuts will mature. He has been through
this before and knows what he is talking about.
Reference was made a short while ago to the pecan as a shade tree. I
think this is one of the big opportunities in pecan growing. Recently I
drove from Louisiana, Missouri, to central Ohio and saw a string of dead
elms along the entire route. Now the oaks are threatened in the same
way. We don't know what to do about shade trees. Some scientists from
Holland visited us several weeks ago and they weren't very enthusiastic
about their disease resistant elm selections. We had hoped that these
selections might provide the answer to the elm tree problem.
Now pecans make very attractive shade trees. I used to live near Kansas
City on a place where someone had planted 18 or 20 pecans right along
the side of a golf course. When the trees were about 20 years old a
fairway was laid out through this pecan grove and now blue grass grows
right up to the tree trunks. A lot of other shade trees are shallow
rooted and lawns do not grow well under them. I think there is a
tremendous opportunity to plant pecans as shade trees.
There is just one other point I want to make. Undoubtedly we need better
varieties. The nurseryman realizes this better than anyone else. But
when my friend from Brunswick sold his native pecans he got just about
as much for them per pound as the southern growers got for their much
larger southern seedlings. Several commercial pecan crackers that I
asked about this stated that the northern nuts have a better flavor and
they produce more kernels per pound. So the size of the kernel doesn't
make too much difference, although we all prefer the larger nuts.
Pecans in Northern Virginia
J. RUSSELL SMITH, _Swarthmore, Pennsylvania_
(Extracts from a letter to the NNGA secretary, November 26, 1951)
Having sold my Virginia cabin and the nursery business [Sunny Ridge] I
have been down to the nursery for the last month getting rid of trees. A
job of digging is one thing and that of packing and shipping is another.
The man I had could do one but not both, and competent persons to pick
up for either job are not available, so I have been standing in the gap,
getting calluses on my hands and getting rid of $16,000 worth of trees.
Now as to facts on northern pecans:
I find the Busseron bears with regularity at Round Hill, Virginia, in a
tight bluegrass sod. This pasture is not of high fertility and has had a
small amount of commercial fertilizer. It is on a hillside that has
probably lost all of its topsoil once or twice in the last hundred
years, though not for the last twenty because it has been in grass.
My neighbor, Henry B. Taylor, Hamilton, Virginia, has Busseron,
Butterick, Greenriver, Indiana, and Major, all bearing well to heavily.
Unfortunately this year the Greenriver hulls did not open, although the
nuts were well filled. Ordinarily I believe they have been dropping
their nuts, but not all at once.
Twenty-five years ago I planted some Butterick and Busseron along a
stream on a dairy farm on which I was born. There was no regular record
of their performance, but I have observed that the Buttericks have had a
good crop in 1950 and also in 1951.[6]
I had previously concluded that the Butterick was almost a non-fruiter,
and quit propagating it years ago. These especially productive
Buttericks are on alluvium near the barn in a permanent pasture where
the cattle congregate while waiting for the gate to open to let them
into the barn. It is therefore fertilized over and over again with cow
drippings.
Mr. Taylor's excellent yields are also produced on trees that are on
unusually fertile soil.
My conclusion is that the pecan is a very active feeder, and what it
needs is about three times as much fertilizer as is required for any
ordinary crop.
It is time somebody better placed than I am made a systematic experiment
as follows:
1. Feed pecan trees at least five times as much plant food as the
nuts and leaves use.
2. Injure the trees by hacking the bark to make them bear, and see
how much they can be made to produce by this means.
A Busseron tree in the town of Round Hill stands in a backyard of a
friend of mine and they use it, I think, to tie clotheslines to and
maybe the boys have had a little fun driving nails into it and it bears
every year.[7]
The real find of my observations is a pecan known as All State, which
has been wonderfully advertised by one of your fellows.[8] On a catalog
it produces a nut two inches long--wonderful. On Mr. Henry Taylor's tree
in Hamilton, Virginia, it produces a tiny, symmetrical, pointed nut too
small to be contemptible, except for squirrel feed. They might have time
to handle the crop.
FOOTNOTES:
[Footnote 6: In the NNGA Report for 1935, Mr. C. A. Reed told of studies
of blossoming habits of pecan varieties at Rockport, Indiana, conducted
for four seasons in co-operation with Mr. J. F. Wilkinson. There the
Busseron was found to be a protandrous variety, shedding most of its
pollen, and in some years all of it, before the period of receptivity of
its pistillate flowers. "With Butterick ... the order was reversed, as
the period of receptivity began first," and it was classified,
therefore, as regularly protogynous. "... Furthermore, upon close
observation it has been found," he said, that trees of the Butterick
variety "develop very few pistillate flowers, and that many of these
wither up and drop off, apparently because of inherent weakness. From
this, it would appear that light bearing is not necessarily due to lack
of suitable or adequate pollen." The Butterick had a record of
practically non-bearing performances during the four years (1931, 1932,
1934 and 1935) at Rockport, which is duplicated by its performance
records at other locations and other years, so it is generally on the
discard list. But when it does bear and mature its nuts it is a good
pecan. Mr. P. W. Wang rated it his first choice of northern pecans
fruited in China.
Mr. Reed listed as protandrous Busseron, Kentucky, Major, and Niblack
varieties, whereas Butterick, Indiana, and Posey were protogynous. He
did not specify in which class the Greenriver fell. Major during each of
the four years, had an interval of 1 to 3 days between the last shedding
of pollen and the first pistil receptivity; Warrick, an obsolete
variety, had some overlap each year as did Indiana and Posey. The
Kentucky, a discarded variety, had overlaps the three years it was
observed. In two years it was observed, Niblack had staminate and
pistillate flowering together one season, and staminate overlapping four
days into the period of pistillate receptivity the next. Busseron,
Butterick, and Greenriver sometimes had overlaps and sometimes
intervals. Reed's conclusion, that "northern varieties of pecan ...
appear to be partly or completely dependent upon other varieties for
pollen," still holds good, as does his second observation, that "all
varieties tend to vary, from year to year with respect to periods of
pollen shedding and pistil receptivity." But more records are needed,
and any members who have two or more varieties flowering in 1952 can
make valuable contributions by taking accurate notes on their
habits. There are now newer varieties for which such data are
completely lacking, and until more is known, no reliable basis can
be had for matching them with the best combinations for adequate
cross-pollination.--J. C. McD.]
[Footnote 7: I think the first phase of the suggested experiment has
more to recommend it than the second. Perhaps the Round Hill tree gets
needed zinc from clotheslines and roofing nails. A more scientific way
to apply zinc is to use zinc sulfate in sprays or ground applications,
and these are to be used on some trees at Urbana which Dr. Crane
diagnosed as zinc-deficient.--J. C. McD.]
[Footnote 8: The Bradley Brothers, who do not court anonymity, are no
fellows of the Association or of the University of Illinois. They have
been known to sell some kind of grafted pecan trees in recent years,
possibly the Stuart or some other variety available from southern
wholesale propagators. Mr. Taylor was lucky enough to have his order
filled with a southern Illinois seedling which at least is good for the
squirrels. We haven't yet seen any All State nuts from Maine or Montana.
The Bradley variety is an obsolete southern pecan.--J. C. McD.]
Pecans in the Vicinity of St. Paul, Minnesota
CARL WESCHCKE
About 25 years ago pecan seeds from the most northern natural habitat in
Iowa were planted in garden soil here in St. Paul. Most of them were
later transplanted in nursery rows at my farm seven miles east of River
Falls, Wisconsin. Out of approximately 300 trees, about 40 are still
living, of which 25 have grown well. The remainder probably have not
found soil conditions to accommodate their natural vigorous growth.
Where the trees are in deep soil with sufficient plant food, they have
done well, the largest tree being about 10 inches in diameter, and
several of these have been bearing nuts for five years. The nuts were
immature, however, but in the fall of 1949 about 70 of the best ones
were planted in a seed bed and today about 15 living trees of pure pecan
parentage represent the second generation.
This evidence is very important, for although the pecan has been almost
as hardy as any native tree (such as the bitternut hickory, the
butternut and the black walnut), yet the length of season required for
the maturing of nuts is a primary factor which would have to be
considered in recommending pecans for planting this far north. However,
it has been my observation that these pecans have slowly cycled their
way into our season, and it is gratifying to notice that this spring
many leafed out at nearly the same time that the black walnut vegetated,
which of course is much slower than the local butternut. This shows the
tremendous adaptability of the pecan, and it is hoped that this ability
to adapt itself to soil and climatic conditions will eventually cause it
to produce small but edible pecans here in the north.
It is my hope, also, that I can use our locally raised pecan seedlings
on which to graft our many successful varieties of hickories, which
heretofore have been limited to some extent in their usefulness because
we had only the local bitternut stocks on which to graft. Whereas the
bitternut is an excellent stock for some varieties of shagbark hickory
and even for shellbark, as well as pecans and hicans, there would no
doubt be an increase in the scope of hickory planting if we had hardy
pecan seedlings as understocks. At first, when comparing the growth of
the native bitternut seedlings with that of pecans, locally raised in
the same soil, it appeared that the pecan was a much more vigorous
grower; but experiments with different types of soil and fertilizers
indicate that we can get seedlings of certain bitternut hickories to
produce from two to three feet of growth in the first year. I have even
found several of these same hickory seedlings of two seasons' growth
which, when transplanted last fall, are large enough to graft this
spring. However, experiments have not proceeded far enough to verify the
practical side of this new idea of hickory propagation.
Only one variety of pecan which was among the original seedlings, and
which existed as a lawn tree for more than twenty years in St. Paul, was
compatible with the bitternut hickory root systems; but enough of this
variety of pecan has been grafted on local hickories to demonstrate that
this is perfectly feasible as far as the union is concerned. In fact,
several of these larger grafted trees have been bearing staminate bloom
for two or more years. No nuts have been produced of this Hope variety
as yet, and although it has been distributed on the market, it has
always been classed as an ornamental rather than a fruiting variety. Of
course, the pecan part over-grows the stock. In other words, there is a
larger diameter above the union than in the stock below the union. So
far, this has not interfered with good growth and hardiness, whereas the
black walnut grafted on butternut (which is a similar combination as far
as results go) more than thirty years ago in experimental work,
indicates that this is a wrong procedure. Very few nuts were ever
gathered from grafts of black walnut on butternut, although in most
instances they continue to live and thrive.
The pecan here is subject to much the same insect pests as the black
walnut, but suffers less from hickory borers and types of insects which
seem to be like oak pruners. This might be useful later on in
maintaining healthy pecan trunks with hickory tops. Probably the early
formation of rough bark, for which the pecan is noted, may be
responsible for this. The nuts that have been produced so far have been
extremely small, but here again the writer has observed an increase in
size over the original nuts that were produced. In some seasons, at
least one tree has produced nuts of sufficient size to be good enough
for home purposes. They are nothing, however, to compare with any named
northern pecans, such as the Major and the Indiana varieties.
Practically all of these northern pecans have been tried in our
environment, and some have lived for several years. Most of them have
died because there was no congenial union of the pecan grafted on our
local bitternut stocks. We do, however, have congenial grafts and good
living specimens of the Norton and the Burton, which are no doubt some
form of hybrid.[9] Hicans that graft well on local bitternut stocks are
the Rockville, first in hardiness and for bearing nuts of the usual size
for Rockville. They do not mature yet, but it is expected that favorable
years will mature these nuts.
Next in hardiness is the Green Bay, and next are Burlington, Des Moines,
Bixby, and McCallister. Although making good growth, these have seemed
to be too tender for our climate, although we have good living specimens
of them and believe that some have begun to bear, particularly the
Bixby, unless names of grafts have been mixed up. These latter trees are
mostly in the deep woods, and it is hard to get close data on their
behavior and bearing.
A Marquardt (which is supposed to be a lost variety of hican) I believe
exists on my place, and I have taken it out of the deep woods, where it
was grafted nearly thirty years ago from scions direct from J. F. Jones,
and have placed scions on stocks in the vicinity of the nursery, where
they can be watched. The differences between the scions freshly grafted
last spring and the known varieties of Rockville, Green Bay, and
Burlington are distinctive. Also the Marquardt (if it is a true
Marquardt) last winter indicated much greater hardiness than did grafts
made at the same time with Rockville and Burlington varieties. However,
it is too early to say for sure whether the Marquardt is represented
among my varieties of hicans. The Marquardt grafted on local stocks used
by Jones and purchased as individual trees, did not survive. It is
assumed in this paper that this discussion would naturally lead to pecan
hybrids, rather than staying with the pure blooded pecan this far north,
for some of the varieties come very close to being pure pecans, but
still, like Norton and Burton, probably are distinct hybrids.
When some of the original seedlings from Iowa were transplanted from the
nursery row they were already quite large trees and we did not get all
the roots. The portions that were cut off were left in the soil. One of
these roots sprouted three trees; one was subsequently moved into the
orchard and marked because of its vegetative nature, and a variety of
hickory known as the Weschcke was grafted on it. It makes a very good
growth, but in most instances our native bitternut stock produces an
equally good growth in unions with this particular variety. This
particular performance is indicative of things to be expected for this
combination in the future.
In conclusion I would say that the pecan is far from being a practical
nut tree for our vicinity, and is only a very hopeful dream. But so,
also, were the best hickory varieties 30 years ago when I first began my
experiments.
FOOTNOTES:
[Footnote 9: The Norton name seems to be shared by a pecan and a hican.
The Burton hican from Owensboro, Ky., is presumably a pecan-shagbark
cross with an excellent nut, fruitful farther south.--Ed.]
Preliminary Report on Growth, Flowering, and Magnesium Deficiency of
Reed and Potomac Filbert Varieties
H. L. CRANE AND J. W. MCKAY[10]
During the course of filbert breeding investigations at the Plant
Industry Station, Beltsville, Md., covering a period of approximately 18
years, the leaves of certain seedlings scorched badly in mid or late
summer. Certain other trees showed little or no evidence of this
disorder. It was thought that, because filberts thrive best under
maritime climatic conditions of cool summers and mild winters, this
scorch was probably due to high temperatures accompanied by deficient
soil moisture.
This breeding work resulted in the introduction in 1951 of the Reed and
Potomac varieties, which were produced as a result of crosses between
the American filbert, _Corylus americana_, and the European filbert, _C.
avellana_. The original trees of these varieties had been under
observation for more than 10 years, and their performance had been such
as to indicate their suitability for home plantings under eastern
conditions. Furthermore, these varieties had shown little or no evidence
of scorch and had held their leaves well.
In early spring of 1948, an experimental orchard, consisting of 36
layered trees each of Reed and Potomac, was planted at Beltsville, for
the purpose of testing them more fully than had been possible before as
to their suitability for eastern conditions. The orchard was designed
also for study of their response in tree growth and fruiting to
differential fertilizer treatments. Although this experiment has been
underway now for only three years, certain of the findings are thought
to be of such importance that a preliminary report should be made at
this time.
Experimental Plan
The site selected for the orchard is a gentle slope varying from five to
15 percent and providing good air drainage. The soil is a Riverdale
(tentative series) sandy loam that had been in orchard grass sod for 10
years before the experiment was begun. Much of the land on the Plant
Industry Station farm is now known to be low in available magnesium and
potassium. Tree crops, including peaches, pears, and apples, have shown
deficiencies of one or both of these elements. The trees were planted 20
feet apart on the contour in pairs, one of each variety in a plot, with
six plots in a row. The 36 two-tree plots were in six rows. Thus, the
experiment was arranged in a 6 by 6 Latin square and six fertilizer
treatments were used. After planting, the trees received frequent
cultivation and a uniform application of one pound of 10-6-4 fertilizer.
The following spring differential fertilizer treatments were applied:
Nitrogen, phosphorus, potassium, complete, nitrogen and potassium, and
check. The amounts applied per tree in fractions of a pound were
elemental nitrogen 0.2, phosphoric acid, 0.4, and potash 0.2. In the
spring of 1950, the amounts applied per tree were doubled; and these
same amounts were applied in the spring of 1951. Nitrogen was applied in
the form of nitrate of soda, phosphorus as 20 percent superphosphate,
and potassium as 50 percent muriate of potash. Strips about six to eight
feet wide on each side of the tree rows have been cultivated frequently,
but strips of orchard grass sod have been left in the tree row middles
to prevent soil erosion. The trees have been sprayed with DDT or
parathion or both to control Japanese beetles and mites.
Growth Responses
To determine the growth responses made by the two varieties to the
differential fertilizer treatments, diameters of the tree trunks one
foot above the soil were measured each spring before growth started.
These data are not given here because in 1949 and 1950 there were no
significant differences in the growth of the trees as a result of the
differential fertilizer treatments. However, trees of the Potomac
variety made more growth than those of the Reed variety. At the end of
the 1949 and 1950 growing seasons, the average diameters of the tree
trunks of the Potomac variety were 16.3 and 25.7 millimeters,
respectively; those of the Reed variety were 13.6 and 22.4 millimeters,
respectively. The differences 2.7 and 3.3 millimeters, are highly
significant. Under the conditions of this experiment, the trees of the
Potomac variety are much more vigorous than those of the Reed. The
greater vigor of the Potomac trees may account for the fact that they
produce suckers much more freely than do trees of the Reed variety. The
habit of producing abundant suckers is an advantage in propagating by
layering, but it is a disadvantage in orchard trees because the suckers
must be removed for optimum nut production. Whether the differences in
vigor and suckering habit of the two varieties shown thus far will
affect their performance as orchard trees will have to be determined by
future observations.
Flowering Response
Each year at the height of the flowering period, each tree in the
experiment was rated on the catkins it carried. So far, there has been
no effect of the differential fertilizer treatments on the production of
catkins. However, there have been very highly significant differences
between the Potomac and the Reed. In 1950, only four of the 36 Reed
trees produced catkins, whereas 32 of the 36 Potomac trees flowered, and
approximately half of them were heavily loaded. In 1951, the number of
Reed trees producing catkins was 12 of the 36, whereas 35 Potomac trees
flowered. The amount of pistillate flowering during the two years was
small on both varieties and not greatly different; this indicates that
their nut-bearing potentialities may be about the same. The amount of
pollen produced by the Reed variety has always been considered ample for
cross-pollinating the Potomac, even though the former has been a light
producer of catkins.
Records of dates of flowering of the two original trees over a 10-year
period, and of these young orchard trees over a 3-year period, show that
there is great variability in time of flowering, depending upon the
sequence of weather events each season. Fertilizer treatments have had
no measureable effect. The trees have shed pollen as early as January
and as late as April, and stigma receptivity sometimes has continued
intermittently for two months. The average period of flowering at
Beltsville is the last week of February to the first week in March. Both
varieties have flowered at the same time under all seasonal conditions
observed. This means that additional pollinators will not be necessary
when the varieties are planted together in an orchard.
Symptoms of Scorch
The visible symptoms of scorch do not begin to appear under conditions
at Beltsville until about the middle of July or later. The first symptom
is fading of the green color, especially around the margins of the leaf
blade. Sometimes this chlorosis results in blotches, which may extend
for a considerable distance from the margin towards the mid-rib. This
stage is of short duration, as the tissues of marginal chlorotic areas
or those of the blotches soon die, roll up, and turn brown. Some leaves
show yellow blotchiness over most, if not all, of the surface and this
may develop into brown patches of dead tissue or the yellow leaves may
fall before the tissues die. The older leaves, those at the base of a
shoot, are generally the first to show chlorosis and scorch, and the
terminal leaves are the last to show such symptoms. On severely affected
trees all the leaves on a shoot may be scorched at the time scorching is
observed. Severely affected trees drop part or all of their leaves
prematurely. The leaves dropped are those that are scorched or that show
yellow blotches. Such trees do not make satisfactory growth, they set
few nuts, and the nuts are usually poorly filled at harvest. The
symptoms of scorch on filbert leaves are similar in many respects to
magnesium-deficiency symptoms on apple (1, 5, 6)[11] and tung leaves
(3).
Leaf Analyses[12]
No differences in appearance of the trees as regards leaf scorch were
noticed the first year after the differential fertilizer treatments were
applied. However, in late July and early August of the second season,
severe leaf scorch developed on the trees that had received potassium
alone or nitrogen plus potassium, and scorch developed to some extent on
the check trees. On August 15, 1950, leaf samples for chemical analyses
were taken from each tree in all replications and composited by
treatments into six samples. The data on the chemical composition of the
leaves as affected by the differential fertilizer treatments are given
in table 1.
These data show that the fertilizers applied to the trees were taken up
by them and that the composition of the leaves was significantly
affected. The trees in treatments 2, 3, and 6, which did not receive
nitrogen in the fertilizer, had lower percentages of nitrogen in the
leaves than those from the other plots. Their light green color
indicated that in the middle of August they were deficient in nitrogen
when its concentration was 2.3 percent or less.
=Table 1. Chemical composition (oven-dry basis) of filbert leaves
collected August 15, 1950, from fertilizer experiment, Beltsville, Md.=
_____________________________________________________________________
| |
Treatment | Composition of leaves | Mg (percent)
________________|__________________________________| Ratio ____________
| | K (percent)
| Ash N P K Ca Mg |
________________|__________________________________|
| % % % % % % |
1. Nitrogen | 6.68 2.52 .129 .945 1.30 .143| .151
2. Phosphorus | 8.56 2.29 .160 .885 1.60 .186| .210
3. Potassium | 9.39 2.31 .150 1.650 1.93 .155| .094
4. Complete | 7.18 2.43 .133 1.175 1.63 .132| .112
5. Nitrogen and | |
potassium | 7.62 2.49 .119 1.480 1.33 .110| .073
6. Check | 7.38 2.32 .188 .890 1.70 .149| .167
Potassium applications produced the greatest effect on leaf composition,
as they increased the concentration of that element in the leaves by
0.285 to 0.760 percentage unit over that in the leaves from the check
trees. In addition, it seems likely that this great increase in the
potassium content of the leaves was accompanied by a decrease in their
magnesium content, since this usually has been found to result. When
the ratios of the percentage of magnesium to the percentage of
potassium in the leaves were calculated, it was found that they were
rather low for the trees that had been fertilized with potassium. The
magnesium-potassium ratio was highest in the leaves from the trees
fertilized with phosphorus only, followed in order by the check and
nitrogen treatments.
Relation of Magnesium Deficiency to Leaf Scorch, Winter Injury, and
Fungus Infection
On August 15, 1950, at the time the leaf samples were taken, each tree
in the experiment was scored as to the degree of leaf scorch present. In
the winter of 1950-51 soil samples were taken from each plot receiving
potassium alone and the lime requirement was determined by the Division
of Soil and Management and Irrigation, of this Bureau. The lime
requirement was found to vary greatly, ranging from 1500 to 6700 pounds
per acre. In early spring of 1951, high-magnesium dolomitic lime was
applied uniformly at the rate of 1500 pounds per acre and in addition
each tree received 5 pounds of Epsom salt.
Each tree in the experiment was scored for degree of winter injury on
May 10, 1951. By August 3, leaf scorch was evident on trees in certain
treatments and the trees were scored for leaf scorch. At this time it
was found in certain treatments that the trees that had not shown any
appreciable amount of scorch heretofore had some severely necrotic
leaves on them. Careful examination revealed many fruiting bodies of one
or more fungi in these necrotic areas. Each tree was, therefore, scored
for the presence of this disease, which has been tentatively identified
by Paul L. Lentz, of this Bureau, as being caused by _Labrella coryli_.
The data on leaf scorch, winter injury, and the fungus disease are given
in table 2.
Table 2. Relation of magnesium deficiency in filbert leaves to leaf
scorch, winter injury, and disease caused by _Labrella coryli_
______________________________________________________________________
Ratio Scorch[1] Winter[2] Scorch[1] Disease[1]
Treatment Mg (percent) score injury score score score
K (percent) (1950) (spring, 1951) (1951) (1951)
______________________________________________________________________
1. Nitrogen .151 1 4 7 9
2. Phosphorus .210 1 3 1 11
3. Potassium .094 21 22 24 3
4. Complete .112 2 5 8 11
5. Nitrogen
and potassium .073 13 19 9 5
6. Check .167 14 6 6 8
Note 1: Total plot score for 12 trees; highest possible score 36.
The scale for scoring was 0, none; 1, light; 3, severe.
Note 2: Total plot score for 12 trees; highest possible score 48.
The scale for scoring winter injury was 0, full leaf, no injury; 1,
few dead twigs; 2, half of buds not growing; 3, very large amount
of dead twigs; 4, only a few buds growing.
Trees that had received potassium alone had the most severely scorched
leaves and more of them on August 15, 1950, followed by those that had
received nitrogen plus potassium. The trees that had received nitrogen
or phosphorus alone showed practically no scorch, each having a total
score of 1; and the complete fertilizer trees a total score of only 2,
while those in the check had a total score of 6. These scores indicate
that scorch is related to magnesium deficiency or unbalance. There was a
close relation between the amount of leaf scorch in August, 1950, and
the amount of winter injury, the coefficient of correlation being 0.97,
which is very highly significant. This coefficient means that 94 percent
of the winter injury sustained could be accounted for by the leaf scorch
present the preceding summer and early fall.
The scorch scores of August, 1951, show that there had been no
consistent improvement from the magnesium-deficiency condition as a
result of the dolomite and Epsom salt applications. The scores for the
disease caused by _Labrella_ show that applications of phosphorus alone
increased the incidence of the disease and those of potassium alone or
potassium plus nitrogen decreased it.
In all cases, the incidence of leaf scorch, winter injury, and disease
were strikingly different on the Reed and Potomac varieties. In the
summer of 1950, the total scorch score of the Reed variety was 26 and
that of the Potomac 18, and in August, 1951, the scores were 36 and 19,
respectively. The total winter injury scores were 46 for the Reed
variety and 21 for the Potomac. Thus, it is clearly evident that under
the conditions of this experiment the Reed variety was much more
susceptible to leaf scorch and to the winter injury resulting from
magnesium deficiency or unbalance between magnesium and calcium plus
potassium than was the variety Potomac. Furthermore, the total score for
the incidence of the disease caused by _Labrella coryli_ on the variety
Reed was 38 as compared with 9 for the Potomac variety. It would,
therefore, seem that the Reed is about four times as susceptible to
infection by this fungus as is the Potomac. Its less vigorous tree
growth, susceptibility to leaf scorch, winter injury, and infection by
_L. coryli_ may be due to the differences between its nutritional
requirements and those of the Potomac variety.
Conclusions and Summary
The preliminary results of the experiment described show that there is a
great difference in vigor, growth, flowering habit, susceptibility to
leaf scorch, winter injury, and infection with a fungus disease
tentatively believed to be caused by _L. coryli_ between trees of the
Reed and Potomac filbert varieties. In all cases the Potomac variety has
been the superior.
It would appear that much of the leaf scorch on filberts experienced in
the past has been due to a magnesium deficiency or to an unbalanced
condition between magnesium and calcium plus potassium in their
nutrition. The symptoms of magnesium deficiency (scorch), which in
general are similar to those on apple and tung, are described. The data
presented show that liberal applications of potassium alone, or in
combination with nitrogen, resulted in a highly significant increase in
the incidence of leaf scorch due to magnesium deficiency. This in turn
resulted in susceptibility to winter injury, the coefficient of
correlation being 0.97, which means that the severity of the leaf scorch
in August, 1950, would account for 94 percent of the winter injury
sustained.
Applications of 1500 pounds per acre of high-magnesium dolomite,
together with five pounds of Epsom salt per tree in early spring of
1951, did not produce consistent improvement in leaf scorch. It seems
that recovery from magnesium deficiency in filberts is slow after
treatment, just as has been found to be the case in fruit trees (2, 4).
Literature Cited
1. Boynton, Damon, Cain, Carlton J., and Van Geluwe, John
Incipient Magnesium Deficiency in Some New York Apple Orchards.
Proc. Amer. Soc. Hort. Sci. 42:95-100. 1943.
2.----
Magnesium Nutrition of Apple Trees. Soil Sci. 63:53-58. 1947.
3. Drosdoff, Matthew, and Kenworthy, Alvin L.
Magnesium Deficiency of Tung Trees. Proc. Amer. Soc. Hort.
Sci. 44:1-7 1944.
4.----, and Lagasse, Felix S.
The Effect of Some Magnesium and Calcium Fertilizers in a
Magnesium Deficiency Bearing Tung Orchard. Proc. Amer. Soc.
Hort. Sci. 56:5-11. 1950.
5. Southwick, Lawrence
Magnesium Deficiency in Massachusetts Apple Orchards. Proc.
Amer. Soc. Hort. Sci. 42:85-94. 1943.
6. Wallace, T.
Magnesium Deficiency of Fruit Trees. Jour. Pom. and Hort. Sci.
17:150-166. 1939.
FOOTNOTES:
[Footnote 10: Principal Horticulturist and Horticulturist, respectively,
U. S. Department of Agriculture, Bureau Plant Industry, Soils, and
Agricultural Engineering, Beltsville, Md.]
[Footnote 11: Numbers in parenthesis refer to Literature cited, p. 55.]
[Footnote 12: The authors take this opportunity to thank Dr. Harald E.
Hammar for making the chemical analyses of the leaf samples.]
Bunch Disease of Black Walnut
[Paper expanded from a talk given at the 41st annual meeting of NNGA in
1950.]
JOHN W. MCKAY, _horticulturist_, and HARLEY L. CRANE, _principal
horticulturist, United States Department of Agriculture, Agricultural
Research Administration, Bureau of Plant Industry, Soils, and
Agricultural Engineering, Division of Fruit & Vegetable Crops and
Diseases, Plant Industry Station, Beltsville, Maryland_
Introduction
For the past several years observations have been made on the
development and spread of the bunch (brooming)[13] disease on _Juglans
nigra_ and on other species of walnut growing in the orchards at Plant
Industry Station at Beltsville, Maryland. Because of the widespread
interest in growing walnuts a brief survey of these observations will be
given in this paper together with a summary of the history of the
disease and a discussion of its possible effect on walnut production.
History of the Disease
The bunch disease of walnut has been known for years. Waite[14] in 1932
said, "It turned up in Delaware several years ago, where quite a variety
of walnuts, including the Persian, the Japanese Group, and the American
Black Walnut, were found to be affected. At Arlington Farm, Virginia,
during the past 15 years it has boldly riddled the collection of nut
trees assembled in the grounds for study and ornamental purposes."
Photographs made in 1914 of Japanese walnut trees growing in Georgia and
thought to be affected by rosette (now known to be caused by zinc
deficiency) have been found in the files of the U. S. Department of
Agriculture. Now that the symptoms of the two different disorders are
known, it seems clear that the bunch disease was present in those two
states at that early date.
Becker,[15] of Climax, Michigan in 1940 reported on his observation of
this disease in that area. He reports that he observed several cases of
it on Persian walnut, Japanese walnut, and butternut, in addition to
many diseased eastern black walnuts. He says, "My conclusions are that
in witches'-broom (bunch disease) we have a very bad disease that
threatens the black walnut trees everywhere".
In 1939, the late Howard E. Parsons, pathologist of the U. S. Department
of Agriculture, made an inspection trip to Climax and other areas in
Michigan where he studied and photographed diseased trees. Parsons at
that time was working on a similar disease of pecan and water hickory
and was of the opinion that the disease found on the various species of
walnuts in Michigan was similar to the one he was studying.
For the past 20 years the bunch disease of walnuts has been under
observation by the writers and it seems clear that its incidence has
increased greatly during that time. In 1935 scions and buds were taken
from diseased eastern black walnut and butternut trees growing at
Arlington Farm and grafted or budded on eastern black walnut stock
growing in the original nut tree nursery at the Plant Industry Station
at Beltsville, Maryland. This was done in an attempt to determine
whether the disease was caused by a mineral deficiency or by a virus.
All buds and scions died, but the following year two of the seedling
rootstocks showed characteristic symptoms of the bunch disease. Since
this disease was already present on the station farm it was not
definitely known that it was transmitted to the stocks by budding or
grafting the diseased material on them.
In December of 1946 Hutchins and Wester[16] presented a paper before the
American Phytopathology Society giving the results of their studies on
the bunch disease. In this paper they reported that the disease was
transmitted by patch bark grafts performed in 1944 and 1945 and that the
incubation period varied from several months to two years. It was
concluded that since the disease was transmitted by grafting, and in the
absence of a visible pathogen, a virus causal agent was indicated.
Symptoms
The characteristic symptoms of the bunch disease are mainly the
production of brooms or sucker shoot growth on the tree trunk and main
branches and the tufting of terminals, profusion of small branches from
axillary buds, the dwarfing and narrowing of the leaflets, and the dying
back of the trees resulting sometimes in the death of the trees. The
principal symptom is the production during summer of bushy, wiry growth
caused by the breaking into growth of lateral buds that normally would
remain dormant over the winter. These buds produce shoots that again
branch from lateral buds and the process may be repeated for three or
four times, resulting in a tightly packed mass or bunch of small, wiry
twigs and undersized leaves. Another characteristic symptom is that this
growth proliferation continues unabated until the first frost, and,
since the wood of these shoots is thus not properly matured, killing
back of the diseased portions of the tree usually occurs with the first
hard freezes of winter.
As the disease progresses, the wood in the main branches becomes very
brittle and is easily broken by wind or ice. This condition is followed
by the dying back of branches and finally the death of the tree. Trees
even moderately affected soon become worthless for nut production, as
few nuts are set and those that mature are usually poorly filled.
Susceptibility of Species
Extended observations show that of the walnut species now grown in
eastern United States, the Japanese walnuts, i.e., the Siebold and
the heartnut, are by far the most subject to attack by this disease.
These walnuts are so susceptible that in localities where this disease
is present the planting of young trees is inadvisable, as they are
almost certain to be short lived. Once infected, will endanger other
walnut trees in the area.
Observations at Beltsville show that the butternut is almost as
susceptible to attack as is the Japanese walnut. Some workers are
inclined to believe that the rather serious decrease in numbers of
butternut trees in some areas is due to the bunch disease. The Persian
(English) walnut is also quite susceptible, although probably not so
much so as the butternut or the Japanese walnut. The eastern black
walnut seems to be the most resistant of all, although some evidence
indicates that at least certain trees of this species may have the
disease but not show symptoms of it. Gravatt and Stout[17] report that
walnut trees may be affected for a considerable length of time without
showing recognizable symptoms. Out of a lot of 300 healthy-appearing
trees, 37 per cent showed bunch disease symptoms following pruning. Only
four percent of the unpruned check trees developed similar symptoms
during the same period of time.
Distribution
At the present time bunch disease is quite widespread in eastern United
States, occurring in Maryland, District of Columbia, Delaware, New
Jersey, New York, Michigan, Ohio, Indiana, Illinois, Pennsylvania, West
Virginia, Virginia, North and South Carolina, Georgia, Tennessee,
Alabama, and probably other States. No special surveys have been made
for bunch disease, and all distribution information has been obtained
from observations of U. S. Department of Agriculture or State workers or
from specimens submitted.
Damage Caused
Trees with bunch disease may live for several years in a stag-horned or
tufted condition. Affected trees generally set few nuts and the nuts
that mature are usually poorly filled and hence low in oil content. It
is likely that a part of the unsatisfactory growth and fruiting
performance of certain eastern black walnut trees may be due to the
disease, even though they do not show the symptoms as they are now
known. Severely affected trees are subject to cold injury, and in
addition the wood becomes very brittle and is easily broken by storms.
Although this disease has been known for several years, it is believed
that its seriousness has not been fully appreciated, as it does not
cause death as soon as symptoms appear. Several years must elapse before
the tree succumbs. In the nut tree plantings made at the Plant Industry
Station at Beltsville, Maryland, large numbers of butternut, Japanese
walnut, and Persian walnut trees were planted. During the following
years, although no records have been kept, several hundred of these
trees have become affected and have been removed. Consequently at the
present time we do not have any butternut or Japanese walnut
trees, and only a few Persian (English) walnut trees left in the
plantings. So far, not a single eastern black walnut tree has been
removed from the orchards because of the bunch disease. Some trees have
shown characteristic symptoms of the disease, but following the removal
of the entire diseased limbs the symptoms have not reappeared.
Possible Effects of Bunch Disease on the Walnut Industry
This disease is known to spread to nearby healthy walnut trees, but the
means by which it is spread or how infection occurs is not known. No
survey has been made to determine whether the disease is present in the
various regions in which walnut trees are grown, and hence it is not
known how widely it is distributed at present. Its spread is probably
associated with an insect vector, and the presence of the vector would
determine whether or not local spread would occur. Much more must be
learned about this disease before its importance and destructive nature
can be fully determined. It seems certain that in localities where the
disease is already present there is little use in planting young trees
of the most susceptible species unless trees in the vicinity that are
already diseased are destroyed. Nurserymen growing trees of the Japanese
walnut, butternut, and Persian walnut should be sure that no diseased
trees which might infect the nursery trees are close to their nurseries.
It is not known how far the inoculum may be carried, but at this time it
would seem that in order to be reasonably safe no diseased tree should
be allowed to grow within a mile radius of a nursery. Infected nursery
trees (or scions) probably constitute the most important means of
long-distance spread for a disease of this type.
Control
The only known method of control of the bunch disease is to prevent
healthy trees from becoming infected. This can be done only by
destroying completely all diseased trees. In the early stage of the
disease, sometimes only one branch on a tree may show symptoms; and
complete removal of this branch may result in the tree's not showing
additional symptoms for a year or more. Except in the case of black
walnut, the disease breaks out again; hence cutting out diseased limbs
cannot be considered a satisfactory control measure, except possibly on
the eastern black walnut.
Case Histories at Beltsville
As a part of walnut breeding work carried on during the past 14 years,
approximately 20 large _nigra_ trees of named horticultural varieties
have been topworked to seedlings of natural first-generation hybrids
between _J. regia_ and _J. nigra_ for the purpose of forcing the
seedling scions into early fruiting. Of these 20 trees, 3 have shown
such unusual behavior as to merit a description of each in the form of a
case history.
_Tree Number 838._ This tree was cut back severely in the spring of
1942, and on August 26, 1943 vigorous new shoots were budded to
47.11-P17, a second-generation seedling of the O'Conner natural
hybrid. The buds grew vigorously in 1944 and early in the season
developed symptoms of the bunch disease. By the end of the growing
season of 1944 the scion limbs were heavy with the typical proliferated
shoots characteristic of the disease. Also, a few vigorous sucker limbs
of the stock tree that grew out from below the point of union of the
scions showed typical symptoms of the disease, although these limbs were
later outgrown by normal shoots and are not now to be seen. In the early
spring of 1945 the diseased limbs were all removed from the tree to
prevent the further spread of the disease in the area.
At the same time that the above seedling was budded in the top of this
tree, a large lateral limb of the stock tree was budded to seedling
number 40.70-P1. This seedling originated from a nut of the Ohio
variety of black walnut that was only about 1/4 the size of nuts typical
of the variety. At the time it was thought that this nut resulted from a
cross of Ohio with pollen of the Persian walnut, as it was produced
under bag and following hand-pollination. Later growth of the seedling
indicated, however, that the pistillate flower was probably pollinated
by _J. nigra_ before the bagging occurred, since only _J. nigra_
characteristics have shown up in the seedling. In 1950, one bud of the
_nigra_ seedling 40.70-P1 has almost completely regenerated the top of
the tree and no symptom of the disease is evident. By contrast in 1944,
almost all of the top of the tree was occupied by diseased limbs, five
in number, of the O'Conner seedling.
_Tree Number 854._ This tree has shown behavior almost identical with
that of Number 838, but three seedlings were topworked instead of one.
All three originated from the Coye hybrid and all were budded on July
27, 1944. Less than one month later all buds had produced a foot or more
of growth, and one to two scions of each seedling reached sufficient
size and vigor to survive the following winter without damage. None of
the scions branched in 1944, and all failed to show symptoms of the
disease. Early in 1945 profuse branching occurred on the one surviving
scion of seedling number 39.03-P2, and by midsummer excessive
proliferation of the buds of primary shoots had resulted in the
formation of a mistletoe-like growth characteristic of the disease.
Scions of the two other seedlings, 39.03-P8 and 39.03-P11, were lost
by wind damage in midsummer, but at the time they showed no signs of the
disease. Most of the shoots of 39.03-P2 were killed during the
following winter, and in April, 1946, the remaining live portions were
removed by the Division of Forest Pathology for use in transmission
studies.
On August 18, 1944, four patch buds of the O'Conner natural hybrid were
placed on one of the main limbs of this tree. One of these buds grew,
and in 1950 has come to occupy more than half the top of the tree. The
remainder of the top is made up of the original stock tree. There is no
evidence of bunching in the tree at present.
_Tree Number 411._ This tree was budded to six seedlings of the Fox
natural hybrid on April 28, 1943. Only one of these lived, 40.45-P4,
and one scion of this seedling in 1950 comprises the entire crown. No
symptom of the disease has appeared in this scion, and the tree is
healthy at present.
On April 8, 1944, small lateral limbs of the tree were splice-grafted to
two Coye seedlings, 39.03-P8 and 41.26-P10. One scions of each grew
vigorously during the summer, and 41.26-P10 first became chlorotic,
then diseased. Seedling 39.03-P8 became chlorotic but at the end of the
season had not shown symptoms of the disease. Both were removed from the
tree early in 1945 and the living shoots used for scionwood in
transmission studies by the Division of Forest Pathology.
An additional case is _Tree Number 795_. This is a grafted tree of the
Graham variety of black walnut that was planted in 1932 within 100 feet
of trees of the Bates and Faust varieties of heartnuts. By 1940 the
latter trees were heavily infected with bunch disease, but it was not
until 1943 or 1944 that symptoms were discovered in the Graham tree. At
this time the heartnuts were removed from the orchard. The Graham tree
has shown only a few small diseased limbs during the past six or seven
years, and in 1950 a fair crop of nuts is in prospect.
Discussion
The following observations should be mentioned briefly before discussing
the questions raised by the case histories:
1. Out of more than one hundred seedling scions from 13 hybrids
topworked on large _nigra_ trees, three have become diseased the
first or second year after the scions began to grow on black walnut
stock.
2. The three susceptible seedlings have all been grafted on
different _nigra_ stock trees, and the three stock trees have since
regenerated only healthy limbs, after removal of the diseased
shoots.
3. Seedlings from a total of 13 natural hybrids between _J. nigra_
and _J. regia_ have been used, and only two of these hybrids have
yielded susceptible seedlings. However, only a few seedlings were
available from certain hybrids.
4. A total of 156 trees of approximately 36 horticultural varieties
has been grown at Beltsville, and only one tree of the variety
Graham has shown well developed symptoms of the bunch disease. Two
other Graham trees have shown slight or questionable symptoms of
the disease.
It should be pointed out that a considerable number of heartnut and
butternut trees were planted at random in the same orchards with the
black walnut trees used in these experiments and at the same time
(1932). In many cases black walnut trees grew within 50 or 100 feet of
the heartnut trees. The bunch disease first appeared on heartnut trees,
the most susceptible walnut species, and spread quickly to butternut,
which is also very susceptible. By 1940 most of the diseased heartnuts
had been removed from the orchards, but it was not until after the
top-working experiments described above were completed that the orchards
were cleared of all diseased trees. It is therefore possible that insect
vectors or other agencies may have spread the disease to the scions of
the topworked seedlings from the infected heartnut and butternut trees.
Number 795 is the only _J. nigra_ tree on the station farm that has
consistently shown symptoms of the disease during the past eight years,
and in 1950 only a few limbs are affected. On the basis of the
admittedly meager information reported here, it can be stated that the
black walnut varieties used in these experiments are more resistant to
the bunch disease than are varieties and seedlings of heartnut and
butternut. That this is generally true is also borne out by the fact
that in the vicinity of Beltsville, Maryland, and the District of
Columbia, practically all dooryard trees of the Japanese walnut are
infected with bunch disease, many of them having already been killed,
whereas relatively few black walnut trees in the area show symptoms of
the disease.
The suggestion has been made that most varieties and seedlings of black
walnut are symptomless carriers of the disease, and only under certain
adverse conditions of environment would symptoms appear. This would
explain why trees that are cut back severely, as was the case with tree
Number 838 described above, show symptoms on the excessively vigorous
shoots of the next year's growth.
Little can be said at the present time about the relative resistance of
black walnut varieties to the bunch disease because nothing is known
about how it is spread from one individual tree to another. The case
histories of trees described in the present paper are considered to be
worth recording because they show that black walnut trees may support
diseased scions and later regenerate apparently healthy tops. In these
cases the trees showed a type of resistance to the disease. However,
there are many cases known, the majority of which are seedlings, in
which black walnut trees became so badly infected with the disease that
nut production ceased and the trees later died. Whether the type of
resistance described in this paper is widely prevalent in the black
walnut as a species will be impossible to determine until more is known
about how the disease is spread.
FOOTNOTES:
[Footnote 13: Several common names have been applied to this disease,
among which "bunch" and "brooming" have most frequently been used. The
authors strongly feel that the accepted common name should be "bunch"
for the following reasons: (1). The term is very descriptive of the
symptoms of the disorder. (2). It is the accepted name of a disease of
pecan and hickory species that is very similar if not identical to the
one occurring on walnut species. (3). The names "brooming" and
"witches'-broom" have already been applied to diseases caused by fungi.]
[Footnote 14: Waite, M. B. Notes on Some Nut Diseases with Special
Reference to the Black Walnut. Ann. Rept. Northern Nut Growers Assoc.
23:60-67, 1932.]
[Footnote 15: Becker, Gilbert, My Observations on Witches Broom Disease
of Black Walnut Trees. Annual Report Northern Nut Growers Assoc.
31:106-109, 1940.]
[Footnote 16: Hutchins, Lee M., and Wester, Horace V.
Graft--transmissible Brooming Disease of Walnut (Abstract.)
Phytopathology 37: 11, Jan. 1947.]
[Footnote 17: Gravatt, G. F., and Stout, Donald C. Diseases Affecting
the Success of Tree Crop Plantings. Ann. Rept. Northern Nut Growers
Assoc. 39: 60-68. 1948]
WEDNESDAY MORNING SESSION
A Forester Looks at the Timber Value of Nut Trees
CHARLES S. WALTERS, _Forestry Department, University of Illinois_
What I am going to say will apply mostly to black walnut since it is one
of our most valuable timber trees, but it also will apply to other
species like hickory, pecan, persimmon. I've never seen papaw or hazel
nut large enough for timber, but the Persian walnut has some value and
the Chinese chestnut is a fair timber tree. All of these species should
be commercially useful if there is sufficient quality and volume
involved to warrant a sale.
What I have to say may not apply five years from now. Persimmon used to
be the main source of material for golf club heads and shuttles for the
textile industry. It no longer is.
Today golf club heads are being made of "Compreg," a wood which has been
impregnated with phenolic resins and cured with heat. The resin is
similar to Bakelite. Thin sheets of wood are glued together to build up
the head, rather than using a single solid piece, and it makes a
considerably better golf club head. The developments in wood use are
progressing just as in many other fields. What the wood specialists are
trying to do is to take low quality material and change it over to a
form which is suitable for many uses for which high-quality expensive
material is now used. The timber buyer now wants a tree of long, clean,
bole with few knots, of large size,--at least 16 inches in diameter at
breast height. In short, he wants high quality material.
What I am saying may not apply to nut growing. Foresters grow trees for
the wood crop, with nuts as a by-product. The first 16 feet of trunk or
the butt log is his main interest. It should be completely free of
limbs, knots, and other defects for at least 16 feet. You can use the
logs above the butt-cut but they usually produce lower grade material.
You have two courses to follow. You can grow wood either in natural
stands or in plantations, and the end product is very little different.
It is probably easier to grow a high quality tree in a plantation than
in the wild. What can be easier than growing a timber tree in the
woodlands? It eventually reaches merchantable size and is harvested.
Well, nature can do better if you give her help. Your chances of growing
a high quality tree to merchantable size are better in the plantation.
About ten years ago Dr. R. W. Lorenz of our Department made a study of
150 plantations growing on prairie soil in Illinois. Thirty-six were
walnut which ranged in age from 22 to 75 years. The one thing we had the
most trouble with was determining their ages. One day we stopped at a
farm and talked to a farmer, and we asked him when the trees were
planted. This man said he could tell us the exact day. "I was a young
lad and a neighbor drove by and said, 'Yesterday Abe Lincoln was shot.'"
So we had the historical records to determine the age of that particular
plantation.
These plantations ranged in number of trees per acre from 46 to 330. The
number of trees per acre has a direct influence on the size or diameter
growth of the timber tree. An eight by eight spacing, or 680 trees per
acre, eventually will be thinned to 200 trees per acre. That gives each
tree proper spacing for best height and diameter growth.
The trees ranged in height from about 31 feet to 85, averaging about a
foot and a quarter in height each year. The average diameters ranged
from about 12 inches to 15 inches. Individual trees, however, ranged up
to 24 inches at breast height (4-1/2' above ground level). Each
plantation had had very little or no care. If some of them had been
cared for, or "managed", their owners would have had a better wood
crop--higher quality and higher quantity too.
Now, as to the growth in the managed plantations. We believe it is
possible to grow 300 board feet per acre per year. Compared with upland
oak, walnut exceeded it in almost all growth factors up to 70 years of
age and then they were about the same.
Of the cultural practices, the most important is probably pruning.
Sawing off the limbs growing on the trunk makes all wood produced
thereafter free of knots. When the trees reach about six inches in
diameter, one should select those he is going to call "crop
trees"--about 200 of these per acre--and spend his time getting them to
timber size and quality. The other trees are removed over a period of
several years, so that you finally have only the 200 high quality crop
trees left. The reason I suggest starting the pruning when the trees are
six inches in diameter, is that that is the size of the veneer core
left after the veneer manufacturer has turned the log for the thin sheet
of furniture veneer. Remove the limbs and improve the quality so you get
a 16-foot log free of limbs and knots. That is what the buyer is looking
for.
I know practically nothing about growing trees for a nut crop, but we
seem to have something in common in growing trees both for nuts and
timber. Just a lot of it is "horse sense", with a few rules of thumb
based upon scientific principles. You must give the crop trees space,
give them plenty of room to grow. In the woods they start to grow in a
dense undergrowth. The young trees soon reach a height where they begin
to dominate their neighbors. There you pick the straight,
thrifty-growing trees for crop trees and favor them in your thinning and
pruning operations. Tree density influences diameter growth of the
trees. In thick stands, trees are usually small and spindly. So plant a
large number to give the crop trees good form, then thin the plantation
carefully to make it grow.
Grazing and fire are very harmful to tree plantations. Most of the
plantations we studied were grazed. A good many were burned. I don't
think nut growers would periodically burn their stands to improve the
nut production. It is the same with growing a crop of wood. Once the
livestock begin to trample or compact the soil, tree growth slows down
and when that happens it makes the tree more susceptible to attack by
insects and fungi.
As to marketing trees, let's assume you have some material you want to
sell. The one thing you want to know is, "how much is it worth?" That is
like me asking you what my house is worth. I understand there are
persons here not only from Illinois and Iowa, but from New York, West
Virginia, Ohio, and Kentucky. Prices on wood products vary not only from
state to state but also within a state as well. The things you ought to
know are the sizes and the grades of the timber that you want to sell,
since they determine price. Now, there are publically employed foresters
available to help you. They know your local conditions. The
manufacturer's markets determine what he can afford to pay you.
For example, we organized some walnut marketing pools in Illinois during
the war. I suppose a half million board feet of Illinois walnut was sold
for gun stock material. One company was buying most of the product of
the pools. Later we found that this company had a market for low grade
stump veneer. Most of the other companies would mark a half dozen trees
for their stumps. This company would buy 35 to 40 stumps. Every buyer
looked at the same quality and quantity of material, since the trees
were all marked. In this case, however, the difference in markets
determined the price the manufacturer could pay.
Another thing that concerns price is what we call "logging chance" or
how easy is it for the buyer to harvest those trees. I imagine anyone
buying trees in Pennsylvania would have considerably more difficulty in
getting them out than he would in Illinois. The differences in equipment
and methods used to harvest the trees all have a bearing on the price
paid the timber owner.
Hickory is commonly sold for handle stock. Wood for striking-tool
handles has a definite restriction in the specifications on the number
of rings allowed per inch of growth. The Federal Government grades
handles on the basis of growth rate. From 17 to 22 growth rings per inch
is specified. Timber buyers don't want logs grown any slower than 22
rings per inch and those grown a little faster than ten rings per inch
may be acceptable.
Now, as to determining the trees to sell. I mentioned a 16-inch diameter
limit. A few trees smaller than this with logs shorter than 8 feet in
length may be accepted if a large quantity of wood is to be sold. It has
to be economically worth while for the buyer to harvest and transport
the wood, or he can't afford to buy it. Each buyer of course has a
different set of specifications. You ought to measure and _mark_ those
trees you want to sell and ask the buyers to bid only on those marked
trees.
Buyers like to approach the timber owner with, "You have some timber I
can use. I'll give you $100 for what I can use." That is the same
approach as if I were to offer $100 for your entire nut crop. You would
probably say, "Let's weigh those nuts so we will have a basis for coming
to an agreement." It's the same way with timber. There are two ways you
can sell your timber. You can either measure your trees and sell on a
volume basis, or you can mark certain trees and state to several buyers,
"I have marked 25 trees for sale. What is your best offer for them?"
Each buyer looks at the same trees, and you have a common denominator
for comparing the fairness of each bid.
For example, we had a farmer in Woodford County, Illinois who had walnut
trees, wild trees, but growing in a pasture grove. I jotted down the
bids that were made. One buyer offered $200 for 27 trees, another bid
$225 for 35, a third bid $265 for 40 or $165 for 35, and the last buyer
offered $425 for 25 trees. The point I am trying to illustrate is that
the farmer, without that extremely high bid, would have been unable to
compare the bids because someone bid on 27 trees and someone else on 35
trees. If all buyers had bid on 27 marked trees, he would have had a
basis for comparing the bids.
Sell on contract. Farm foresters have simple contract forms which they
will give you. The forms can be filled out so that they tell what you
agree to do and what the buyer agrees to do. Both parties sign the
agreement, so there is less chance for disagreement later.
May I have those slides? (Picture showing large tall tree in dense
forest.) This isn't a walnut tree, but I want to show you the kind of
condition foresters like to see trees growing under. Nice tall stem,
free of any limbs, good diameter. These trees show a rather wide range
of age classes. When I talk to my folks about growing timber, they say
"70 years is a long time to wait for your money." Here is a tree that
started 70 years ago and is ready to be harvested. The crop is sustained
yield.
I put this in to show you what we don't like to see. (Picture showing
park-like stand of timber.) When these 100 or so trees are gone, there
will be no others to replace them. Cattle have grazed this stand to the
extent that it will be a long time before any other age classes develop
to replace those you see in the picture.
That is a white oak. I told you there weren't many. Good diameter all
the way up clear of limbs. When the logger cuts that tree he will have
high quality material. The same applies for walnut, hickory, or any
other species.
This walnut tree shows you how to mark trees for sale. One mark up here
so the buyer knows which tree is designated for cutting, and one down at
the bottom so you can assure yourself that that tree was to be sold. It
identifies one of the trees you intended to sell; a penalty is involved
for cutting any others.
I wanted to show you what a good walnut stump-cut looks like. These
trees should be 18 inches or larger in diameter at about two feet above
the ground to be worthwhile. The stump will be cut off when it gets to
the mill, and peeled for veneer.
This is one of the walnut plantations cut for gun stock material. I put
this in to show you how the buyers cut the trees down, and measure off
the logs to get the best grade of material. They aren't interested so
much in volume as in lumber. They want the best grade of wood, and they
want it in that butt log.
I put these in to show poor quality logs that weren't worth taking. This
is an open pasture grown tree. No care or attention given it, so the
limbs stayed on and grew quite large.
This shows how they load logs with a tractor and chain. This "cross
haul" is a trick of the logger's trade. This is the improper way. The
tractor was broken down so it took five or six men to load it because
they didn't have the tractor. There are some good logs and here are some
poor logs.
This is a group of logs, at a railroad siding. Some look small, but at
that time--with the market as it was--they could use the smaller logs.
You see some of nice length, good form and free of defects. I mentioned
metal. Here's a man with an Army mine detector. They tried them out to
locate metal. This company uses this mine detector to test all logs for
metal content.
Here's what happens. The metal discolors or stains the wood. This tree
probably grew in a fence line. The buyers are just a little reluctant to
buy them. If they do they cut them off this high so they are pretty sure
all fence wire is left in the stump portion.
In this grove of walnut a wire is nailed on every tree. Such a practice
ruins the tree.
This shows wasteful practice. This small mill in southern Illinois was
buying these short bolts cut from small trees. Be careful that you don't
sell trees that are too small and too young. It is like, I suppose,
harvesting your walnuts before the kernel develops.
This is the result of fire. That log, from outside appearance, didn't
have a blemish. Loggers left this part because it was hollow. The
infection developed from a fire scar and rotted out the inside.
This shows the same thing. Fire scarred. Bumping machines used to
harvest the nut crop or any defect or injury may result in something
like this and decrease the tree's value for timber.
I mentioned hickory. Here are some single-trees that are made out of
pecan. Hickory is also used. Hickory grows to a commercial size in
southern Illinois but in most states it is too small and knotty. One
time the Peoria office of the WPB got a release from Washington
indicating that hickory was needed for axe handles. They released it to
the newspapers. We answered letters for a month after that. Farmers who
had hickory they wanted to sell had to be told that there wasn't enough
hickory involved to make it commercially possible to market. In
addition, there wasn't a single handle mill in the state at that time.
This is a couple of loads of good walnut logs. They were cut in Illinois
and trucked to Indiana to be manufactured into veneer and lumber.
Dr. Colby has asked me if I had any methods of getting rid of stumps. We
have worked for five years and we still haven't a method that is
economical or easy. We recommend grubbing or burning them out with a
small stove, or you can cut them close to the ground and let them rot
out. What about the chemicals?--We have worked for a good many years and
we have bored stumps until our arms ached, but we haven't found any of
them that work.
Discussion
MEMBER: 300 board feet per acre per year?
MR. WALTERS: I said we felt that on good soil and by encouraging nature
we can grow that volume.
MEMBER: What are the stumpage prices?
MR. WALTERS: Ranging from about $10.00 per thousand board feet to $300.
There is quite a span and each grade is different. There is a prime
grade, which is the best grade, which must be 16 inches in diameter at
the small end at least. Each company has a little different set of
grades. Even with the same grade the prices will range according to the
size of the log. Maybe a 16 inch prime log may be worth $200 per
thousand board feet and 24 inch will be $300.
MR. CRAIG: Curly walnut would be worth more?
MR. WALTERS: Yes. It is somewhat of a guess as to whether a tree will
have a curly figure. If you let them take the bark off a tree, the
buyers can tell. I know of one beautiful stump on which the buyer wanted
permission to remove part of its bark to see if it had nubby growth. If
it had had the figure, it would have been very valuable. The farmer
said, "I don't want you cutting on that tree because if it doesn't have
the figure and you don't buy it, the tree will be spoiled." Don't let
the buyers chop into the tree to see whether it has figure.
MR. CRAIG: I bought two to get grafting wood.
[Editor's note: Mr. Craig refers to the Lamb curly black walnut, article
on which appeared in NNGA 39th Annual Report.]
MR. WALTERS: There has been some work done on grafting or stimulating
growth for figure. One method was to beat the trees with a rubber hose
and try to stimulate figured or curly grain. Not too much has been
published on this work as yet.
MEMBER: Do you think the figure could be propagated by asexual
propagation?
MR. WALTERS: I don't know. I will say this; in forest trees, the
inherited characteristics are the things we depend upon. If a tree has
curly figure and the seed carries that characteristic, you may see it in
the progeny. An acquired characteristic I don't think you can depend on
so much.
MEMBER: Is it thought to be acquired or hereditary?
MR. WALTERS: I just don't know whether it is acquired or hereditary.
DR. ROHRBACHER: One thought came to me on this black walnut timber. It's
a long pull, and it is one for our posterity. The thought came to be
that it is for those of us who are interested in setting up something
for our offspring. The plan has been brought out before of using a
grafted known name variety of nuts. Plant those, and perhaps those trees
as they grow would first give us that wonderful nut which we were
looking for.
Symposium on Nut Tree Propagation
F. L. O'ROURKE, _Leader_
MR. O'ROURKE: I believe if you get 10 nut people together, you are going
to have eight or nine propagators. It is the one thing that people like
to dream and talk about.
I went through the list a little bit, and in order to save some time I
wrote a resumé of what had been done. In order to accumulate that
material I had to dig into some of the more or less unused volume. There
is a wealth of information in some of those earlier reports of the
Northern Nut Growers Association.
MEMBER: You can get them for $15 a set.
MR. O'ROURKE: It's a good investment anyway. At any rate, I think I am
going to try to make a bit of an analogy. Suppose this was a church
group who had been working on paying off their mortgage. Every once in a
while they passed a hat, but instead of dumping that hat on the table
they let those contributions accumulate, so that after a while they had
the accumulation of 41 years in the hat. Someone has to dump the hat
sometime and I tried to do that this summer, and I found all sorts of
contributions in that hat. We might say this happened to be the hat. You
would find some brand new fresh ten dollar bills, nice new currency, and
then you would find some gold pieces (before Roosevelt). They too can be
used because they can also be converted. Then you could dig back and
come across some stuff, and you didn't quite know what it was. It might
be a Spanish doubloon or an old brass button. Right there is where you
need a little knowledge. You should be able to tell the difference. I
don't know whether I was able to tell that difference. We will, of
course, find a lot of slugs and buttons and this and that among the
valuable pieces, so possibly we should sift those out and put them in
the discard. You never can be sure what to discard.
Just as I said, every nut grower is a propagator at heart. A little wee
paragraph may be a lead to something which would be of quite a lot of
value.
This little brief resumé I passed around yesterday, and now this morning
I am using my school teacherish techniques in passing around a sheet of
paper. There is merely an outline. Pardon me if I insult your
intelligence in getting out that outline. As you notice, we start out
with the seedling and end with nursery practice. This outline should fit
almost any nut species. It should fit chestnut, hickory, walnut or any.
I thought it might be best to have a vote as to which one we talk about
first, and then we will run down each particular species. I think we
should have our panel come up front.
As I said a while ago, we know that practically every person in this
room is a propagator. In order that we have this panel conducted in an
orderly way, please raise your hand when you speak. I will get the
question and pass it to one of the panel members. Which one shall we
take up first?
MR. McDANIEL: Let's take the hard one first, the Chinese chestnut.
All right, chestnut. To be systematic, let's talk about seed. Anyone
having any difficulty? No trouble at all. Who grows most of the Chinese
chestnuts, germinates most of the seed?
MEMBER: I have trouble with rabbits, squirrels, ground hogs.
MR. O'ROURKE: He wishes to know of something to protect his chestnuts.
DR. McKAY: We don't plant in the Fall. I know of one person who uses red
lead. We have never used it. I know that has been done. We store our
chestnuts in cold storage over the winter and plant in the Spring.
C. S. WALTERS: May I interrupt? We tried 50 chemicals, treating walnut
seed with them or putting them on the seed spot after the nut was
planted. The squirrels lifted every nut except those that wouldn't have
germinated anyway. The rascals knew the difference. We tried
allylisothiocyanate--"tear gas." The squirrels would dig those nuts up
and when the vapor got too strong they would go away and allow it to
evaporate. Within two weeks they would come back--maybe two or three
times--before they finally took the nut. We tried cayenne pepper and
n-butyl mercaptan--the main ingredient in "polecat essence." We had
squirrels all over our test plots, and the only nuts they didn't take
were the bad ones.
MEMBER: I have had every other kind of rodent. I found I have to plant
in the spring and always in a tin can, with rock wool over the nut.
MEMBER: We have used rock wool; planted in the spring. They will get
them any time.
MEMBER: I did the same thing with chicken wire and no squirrels got
them.
MEMBER: I would like to ask Mr. Chase if he has planted chestnuts on a
quantity basis.
MR. CHASE: We planted them on a quantity basis and as some of you know
our nursery is adjacent to a wooded area where you would assume there
would be a lot of rodents and polecats, both kinds--four and two legged.
I made that statement once before about never having had any squirrel
damage. We don't have any trouble. We do not lose chestnuts. We mulch
with composted mixtures.
MEMBER. They claim sawdust will help keep them away.
MR. CHASE: On the other hand, a gentleman wanted to get started with
chestnut in the Smokies. We helped him get lined up and he planted in
beds and these are perhaps a hundred feet long. We mulched heavily with
sawdust. The area had been cut over six to eight years ago and had
immense piles of sawdust. We mulched with about four inches and some
animal got every chestnut out. We never knew what animal it was. There
wasn't any evidence on the top. They got every chestnut which was quite
a shock to him. I brought this point out that there _was_ danger and he
was going to build the bed up high and cover with wire or he was going
to get some of this old camouflage netting type and cover that bed for
protection both against rodents and early spring frost. He didn't follow
through on that so I don't plead guilty.
MEMBER: Does the Chinese chestnut seed have a rest period?
DR. McKAY: For some years we have had a friendly discussion with the
Division of Forest Pathology in regard to whether a chestnut seed has a
rest period in the same way black walnut, hickory, or some of the others
do, and we are not absolutely set in our opinion on the matter. We have
the opinion that the Chinese chestnut does not require a rest period. I
will tell you that one species, the Allegany Chinkapin _(C. pumila_)
will germinate very readily as soon as it is matured. It will start
growing immediately. When you go into the oak species, you have a number
like that. They fall to the ground, and put a root into the soil, become
anchored, and grow slowly all winter long. We feel that the Chinese
chestnuts are of that type. Perhaps the old American chestnut was that
way. It fell to the ground in the fall and it sprouted rather promptly
within a month or so and grew slowly. Perhaps the Chinese chestnut is
not so much inclined that way. We have done this: we have taken them
from storage at various times during the winter and planted them, and
have never failed to get reasonably good germination. Others have. The
results there vary considerably. Perhaps we can't be too sure about the
matter. We simply feel that on the basis of what we have seen and
observed, they do not have a definite rest period. Many of the failures
that have been obtained have been due to poor storage conditions, where
the nut started to spoil and perhaps the workers didn't realize it and
planted that nut and the nut spoiled immediately. So you fail, not
because of the inability of the seed to sprout, but because it was
improperly handled and could not grow.
MR. O'ROURKE: Is it not a fact that ... seed has no true rest period as
we know it with trees? On the other hand, about 30 days' exposure to low
temperature and moist conditions will cause all those seeds to germinate
immediately. It may be somewhat the same with chestnut seed.
MR. STOKE: In confirmation, I furnished a man some seed some years ago
and we put them in flower pots and they were a foot high by Christmas.
MR. McDANIEL: The growth is normal from the immediate planting, too. You
don't get the suppressed growth later, as in prematurely germinated
peach.
MEMBER: The chinkapins will often sprout even before they come out of
the bur.
MR. CRAIG: I might say this concerning the California Persian walnuts.
Take one at harvest and plant it, and that seed will germinate
immediately. You hold it in dry storage and plant in the spring and it
will come up in a couple of weeks. I speak from experience.
DR. CRANE: The same thing is true with pecan, in west Texas and Arkansas
and California. We have lots of trouble with pecans germinating. It is
not uncommon to find a pecan germinated with a root as much as ten
inches long grown in the hull. If that nut goes through to maturity and
becomes dry, then there is an appreciable delay in germination. They
won't germinate as quickly. There has got to be a lot of changes in the
kernel after they have once dried out and been harvested before
germination will be initiated again.
DR. McKAY: In connection with this question of germinating nut seeds of
all kinds, we think it is very important to plant the seed in a well
aerated medium. I think that is a mistake many people make. If the soil
happens to be of a clay nature, it keeps out oxygen and air and the
sprout will rot. That is the reason why, when we plant chestnut seed, we
like to plant in sand or the same with any nut seed. Coarse sand has a
lot of air in it. That nut has a high demand for oxygen.
MEMBER: In the matter of chestnut seed, don't put too many layers of
seeds. One is better than two. Even in rather porous soil, they seem to
develop gas. Anyway, I found the bottom ones didn't get enough air and
they rotted, whereas on top they didn't. It is better to plant a single
layer than more.
MR. SHERMAN: What is the best method of treating the chestnut seeds in
the fall to prevent the development of weevils?
DR. McKAY: Of course, there are several ways of treating the nuts for
weevils. One is the old hot water method. All of us can heat water. We
have to heat it to about 120 degrees. So hot, you can't hold your hand
in it. Immerse thirty minutes for an average size nut. Now in connection
with the spoilage and rotting that is another matter. We believe in
harvesting chestnuts promptly, storing them before they dry out. We of
course store our chestnuts in cans. Cans with lids and holes punched at
either end.
MR. O'ROURKE: Are there any other questions pertaining to seeds?
MEMBER: I would like to caution persons outside the weevil belt about
being very careful if you get nuts that may be infested. Leave your nuts
in a small jar and you have the advantage of watching the weevils
actually emerging. You can pick the nuts out about February, and you can
select all the nuts that are sound. Once in awhile a weevil will live
through the winter. One thing we should all be thinking about is that
the nurseryman has to produce grafted trees in order to fill a demand,
and those nut trees must be produced cheaply and he must use methods
which are highly efficient.
MEMBER: Has anyone tried to deep freeze?
DR. CRANE: We tried that just this past winter. For a couple of years
back one individual had asked us why we didn't freeze them. Last winter
we did. We stored three gallon buckets at two temperatures. One at zero
and the other at ten degrees below--hard freezing temperatures. Those
nuts stayed frozen from early October until the next April. We brought
them out and examined them one morning. The first thing we did was taste
them. Those nuts we ate when first opened and you could tell them from
no other chestnuts. They were nice eating, sweet. We let those chestnuts
thaw evenly at room temperature. That evening we examined them and it's
hard to describe what the transformation was in those nuts. In the first
place was the deterioration that had gone on as soon as the tissue
thawed ... They were dripping water. The tissue had burst and the water
just flowed. On the other hand, about an hour after they thawed out,
when we first examined them just as they thawed out, you would be amazed
at how tender they were. They would melt in your mouth. Freezing
apparently breaks down the tissue. The tissue is as soft as it can be.
Apparently this freezing transformed some of the starch to sugar. The
rub is that it won't keep for even two or three hours.
MEMBER: They might keep if you put them in the soil first.
DR. CRANE: The tissue is ruined.
MR. O'ROURKE: We have now decided certain things pertaining to seed
germination. Then we are confronted with the problems of seedling versus
clonal rootstocks. I do not know whether or not there have been clonal
rootstocks selected for Chinese chestnut. I am sorry to have to ask Dr
McKay to talk again but he knows more about it.
DR. McKAY: I can only tell you about the experiment we started this
spring on clonal stocks of chestnuts. We have just this year's results.
Unfortunately we didn't get good results. We took ten seedling trees. We
used nursery trees, large five-year old trees, with vigorous root
system, ten seedlings, and got from them 20 roots. We took roots the
size of your finger with a lot of feeding roots, and we grafted onto
those five times four. We took four per variety. We used five varieties
of chestnuts, and all five of those each had four pieces and we had ten
of those seedlings. We wanted to find out whether any of those ten
seedlings would give us a better set of these five varieties than any
other trees. In other words, we are trying to get a start on a clonal
rootstock. We used a splice graft. We simply took a piece of scion and
spliced it right on the end of the root. We had four of those in the
bundle, and we had five per seedling and we had ten of them. That made
20 in all. We planted in a cold frame, with cheesecloth covering to keep
the temperature from getting too high. Eventually, if this thing works,
we will establish a clonal line. We planted those ten original trees but
you will be surprised. We can go back to the original tree if we
succeed with clonal lines, so a chestnut variety we hope will be
grafted on a line of stock that came from that one original tree. Bear
in mind this is the method and it remains to be seen whether it is going
to work for chestnuts.
The results are discouraging. Only one or two seedlings gave us six or 8
successful grafts on all the five varieties but by that method of trying
all five of these varieties on all ten of the seedings we hope to get a
start. We will try them again, and we hope to get at least a start that
will work. It may be that we will have to start over again. We may want
to take ten other seedlings. That is, in brief, our work so far in that
direction.
We took it off the ground. We didn't have long enough side roots.
MEMBER: How about mound layering?
DR. McKAY: We tried cutting off at the ground level and mounding up
those sprouts and tried to root them, with no satisfactory results.
There was just a small amount of rooting.
MEMBER: Did you try layering?
DR. McKAY: One year we did, but with no success.
MR. McDANIEL: I have seen a few layered successfully but it's a little
slow.
MR. O'ROURKE: Shall we move to vegetative propagation and consider
cuttings first?
DR. McKAY: Just one thing I think ought to be mentioned at this time. We
know that even the use of clonal rootstocks does not entirely eliminate
variability. All the work that has been done with these Malling apple
stocks shows that, as far as apples are concerned. Now we have an idea
which, in a crop like chestnuts, may have very far reaching influence
and we feel quite hopeful for it. That is growing seedling progenies of
certain parent trees. I want to tell you our experience with it. We
started our work on breeding and selection of tung nuts in 1938, and we
have tested now over 600 parent trees that were especially selected. Out
of those six hundred we have released a total of six horticultural
varieties, for asexual propagation. But out of those six we have three
trees, the seed of which will produce seedling progenies that come very
true to the type of the parent tree. One of those released we know as
the Lampton variety. It will produce from 95 to 100 per cent of its
seedlings, that are so true to type that you can identify them in the
nursery. At the end of the first season you plant 95 to 100 per cent of
the remaining trees in the orchard and anybody can identify the trees.
In the case of budded trees we have the variability of the rootstocks,
which affects the growth. Since that particular variety has been
released there has not been one single nut of that variety crushed.
Every single seed is grown to tree size, to plant in a new orchard. It
has taken us 12 years to reach that stage, but that one variety is
probably the most outstanding thing we have. There is a slight variation
in the trees but not as much as you have in other trees.
Now, with Chinese chestnuts, we planted seedlings that were grown from
the seed of a parent tree at Beltsville. We planted a thousand trees.
There were seedlings grown from seed produced by different parent trees.
Out of those thousand there wasn't a single one outstanding. Yet in one
lot of seedlings which was planted in Georgia, every one of the
seedlings grown from the seeds of that selected tree produced such high
quality nuts that we haven't cut out a single tree. There just hasn't
been any off types. Now we have gone a step further. We had one called
selection 7932 which came into bearing very early. We have had those
trees grown from seed. The seedling at three years of age produced a
pound of nuts, the seedling having the characteristic of its mother. We
have hopes that before many years we shall be able to produce parent
trees or clonal lines in which the seed taken from those line and
planted will give us uniform seedlings.
I don't want you folks to get the idea we have these parent trees or
seed from them that are available. I mention it because a lot of you are
growing chestnut trees and planting them from seed. You could make a
great contribution if you would take the nuts from each individual tree
and plant separately, so that you will know in the future the origin of
every one of those seedling trees you have. Some of these days someone
is going to find one that is going to give us seedling trees that are
good and free from variation.
Elberta peach seed will come practically true to variety from seed,
except minor variations of size, shape, color and season. In a peach you
are facing a very highly specialized market. But with the Chinese
chestnut, color is not so important. What we are interested in is trees
that bear and have enough uniformity so that we don't have pee-wees by
one and jumbos by another.
We need very badly this sort of thing. We need chestnut varieties
planted in pairs in isolated places. Any of you folks could do a great
service if you will let us know wherever trees occur in pairs, or just
two varieties and no others, and then we know that one variety
pollinates the other. When you have a mixed planting of a half dozen
varieties the male is promiscuous. Therefore you have a much greater
mixing of genetic factors. If we have a pair of trees, we get a much
more uniform breeding group of seedlings.
MEMBER: How far removed from other varieties do they have to be?
DR. McKAY: Half a mile or a mile.
MR. O'ROURKE: I think we can go to vegetative propagation of cuttings. I
think that we have any amount of evidence that Chinese chestnuts can be
rooted from cuttings, but can trees grow on from rooting cuttings?
DR. CRANE: You have summed up the situation perfectly.
MEMBER: Just by accident, in our storage house a couple of chestnuts
fell over into a pile of peat moss and they did make roots.
MR. CORSAN: Would you call the Chinese chestnut a second?
MR. O'ROURKE: We should confine this only to propagation. While there
are any number of interesting phases of it, we have to stick to
propagation or we will never get through. We have had remarks on layers.
Any comments on layers?
Let's move on to graftage. We want to have our chestnut produced on a
quantity basis so I am going to ask Mr. Bernath to tell us a good
method.
MR. BERNATH: I don't graft too many outside, but I do my propagating in
the greenhouse. I had more than a thousand graftings growing, some of
them this high [indicating] which greatly depends upon the root system
and the condition of the soil. I think that is the fastest and easiest
way of grafting chestnuts. I do my grafting sitting down.
MEMBER: That's on the potted stock.
MR. BERNATH: That's right.
MEMBER: After you have produced all these grafts, what are you going to
do with them?
MR. BERNATH: Sell them.
MR. STOKE: I tried to contact some nurseries. They are selling your
seedlings, little chestnut trees for $1.75 and they want to give you 75¢
or a dollar for grafted ones.
MR. O'ROURKE: Mr. McDaniel has received a letter from Mr. Hirschi from
Oklahoma City and there is one paragraph that I think the membership
will be interested in. [Letter from Mr. Hirschi is partly reproduced
here.]
Oklahoma City, Okla.
Aug. 23, 1951
Mr. J. C. McDaniel,
Urbana, Ill.
My Dear Mac;
... In my work with chestnuts I believe I have had an experience
that will be interesting to the membership. As you well know I am a
strong believer in selected named varieties. I do not regard
seedling chestnuts any more valuable than seedling peaches or
apples. The--Nursery, a member of our association, have been
customers of mine for a long time. Last year I persuaded them to
catalog seedling chestnuts at about half the price of Nanking,
Meiling, Kuling, and Abundance. I was anxious to learn the attitude
of the public, where they had an opportunity to buy and plant
selected grafted varieties, when heretofore only seedlings were
available. To my utter amazement the seedlings did not sell at all,
but the thousand trees of selected varieties were sold out long
before the season was over. I could not supply more, neither could
I get them elsewhere. So far as I know Max Hardy and I are the only
ones grafting chestnuts in quantities.