Today I would like to discuss for a few minutes the possibilities of nut
trees for shade and nut production in permanent pastures on Ohio farms.
One of the most important developments in Ohio agriculture during the
past decade has been improvement of pasture land through fertilization,
new varieties, and combinations of grasses and clovers, and better
methods of management. As one drives over the State it is evident that
many farmers practice "clean" agriculture which means clean fence rows
and treeless fields. Shade on a hot summer day is an important item to
contented cows, so today I am going to plead the case for a cow out on
pasture on a sweltering day. I believe that nut trees, particularly
black walnuts, can be of real service in the fence rows and the interior
of hundreds of permanent pastures in Ohio.
In 1939, L. R. Neel,[7] of the Tennessee Agricultural Experiment
Station, published an interesting article on the effect of shade on
pasture. The results indicated distinct improvement in the carrying
capacity of the pastures which had black locust and black walnuts spaced
regularly throughout the fields. Improvement was evident both in the
amount of Kentucky bluegrass and the pounds of beef produced. So far as
I know, no evaluation has ever been made of the direct effect of shade
on the contentment and consequent increase in efficiency of cattle for
either beef or milk production. I believe this is an important factor
and is frequently used as an excuse for woodland grazing.
[Footnote 7: Neel, L. R., 1939. The effect of shade on pasture. Tenn.
Agr. Exp. Sta. Cir. 65.]
Another study similar to the one in Tennessee was conducted by R. M.
Smith in southeastern Ohio during the period 1939 to 1941.[8] Dr. Smith
made an intensive study of the effects of black locust and black walnuts
upon ground covers and he found that in poor pastures black walnut trees
improved both the species composition and chemical content of the plants
growing under the trees. He rated walnut high as an ideal pasture tree
because of its period of leaf activity; its light crown canopy; its
small, fragile leaves which decompose rapidly, and are high in mineral
matter and nitrogen; its deep tap root which competes very little with
the surface rooted grasses for moisture and nutrients; its hardiness;
and finally its high commercial value.
[Footnote 8: Smith, R. M., 1942. Some effects of black locust and black
walnut on southeastern Ohio pastures. Soil Science, Vol. 53, No. 5.]
It seems apparent, therefore, that the introduction of improved black
walnut trees into permanent pastures would be practical from the
agronomic angle to say nothing about the beneficial effect of shade to
livestock and possible income from occasional crops of high quality
nuts.
One stumbling block to the adoption of this idea is the protection of
the trees during the period of their establishment. The conventional
cattle guard with three or four long posts supporting a wire fence is
expensive in both labor and materials.
During the spring of 1946 in connection with my forestry instruction at
Ohio State University, I had as one class project the planting of 50
black walnut seedlings of selected parentage in the cattle and poultry
ranges on the University farm. Thirty of these trees were planted along
a fence row at 32 foot intervals and were protected by a single electric
wire connected to a battery charger.
The set-up is illustrated in figure 1 which shows the charger at one end
of the line and the wire supported by the line posts and a short single
post opposite each tree. The one year old seedlings were planted 4 feet
from the fence at alternate posts and the wire zig-zagged along the line
to create the guards around the trees. Within a few days after planting
and completion of the electric guards the trees were mulched to control
weeds and conserve soil moisture.
While this experiment has been in effect for only one growing season,
the results, to date, indicate that this method is effective in
providing protection from livestock. Growth and survival of the trees
has been very satisfactory thus far.
The advantages of this method appear to be the rather low cost of labor
and materials and ease of installation.
Within the next decade, we should be able to determine how the nuts from
these seedling trees compare with the parent tree and there should be
adequate shade for all classes of livestock on either side of the fence.
How Hardy Are Oriental Chestnuts and Hybrids?
By Russell B. Clapper and G. F. Gravatt Plant Industry Station,
Beltsville, Maryland
One of the questions most frequently asked in regard to the Oriental
chestnuts is, will they thrive in a given locality? Broadly speaking,
with respect to temperature requirements these chestnuts have been found
about equally hardy with the peach. Some strains of the Chinese chestnut
appear to be superior to the Japanese chestnut in hardiness.
The Chinese chestnut is more widely planted in this country than the
Japanese chestnut and more information has been collected on the
hardiness of the former species than of the latter. The Chinese chestnut
is growing satisfactorily in certain plantings as far south as Orlando,
Fla. and the other Gulf States, northward to the southern tip of Maine,
and westward as far as Iowa. But many areas within this large zone are
unsuitable for growing Chinese chestnuts because of more severe climatic
conditions.
Specific data have been obtained relating to several types of winter
injury of Oriental chestnuts and hybrids. This information is limited to
the performance of mostly young trees and to a comparatively small
number of locations.
The fall freeze that occurred in mid-November, 1940, was studied in
detail by Bowen S. Crandall,[9] formerly of this Division. Widespread
damage occurred to Oriental chestnuts in the central parts of South
Carolina, Georgia, and Alabama. Temperatures before the freeze had been
mild, and heavy rains in early November had broken a drought. On the
nights of November 15 and 16, temperatures of 12 deg. and 14 deg. F. were
reported by various farmers, and a drop to 20 deg. F. was general on the
night of the 16th. The damage to chestnuts by this freeze was increased
because of the mild temperatures and heavy rains that preceded the
freeze. The chestnut trees were not able to attain complete dormancy.
Those trees, however, that were growing on uplands or on sites that were
well air-drained suffered much less damage. Apparently equal damage was
inflicted to Chinese and Japanese chestnuts.
[Footnote 9: Crandall, Bowen S. Freezing injury to Asiatic chestnut
trees in the South in November, 1940. Plant Disease Reporter 27:392-394.
October 1, 1943.]
On one farm near Columbus, Ga., four plantings were located at different
elevations. The planting at the lowest elevation, maintained as a well
cultivated orchard, suffered almost 100 per cent loss from this fall
freeze. The trees at the highest elevation, in a forest planting, were
practically uninjured. The damage from this freeze varied from killing
of buds and shoots to killing of complete trees. Many owners of chestnut
plantings did not notice the damage until the following spring.
Fortunately fall freezes of this magnitude occur only infrequently.
In the winter of 1944, this Division lost 23 per cent of its hybrids at
Glenn Dale, Md., from freezing following abnormally high temperatures.
The hybrids had been fertilized in October of the preceding year, but
the effect on the extent of freezing damage is not known. The months of
November, 1943, through March, 1944, were characterized by extremely
variable temperatures. For example, in November a minimum of 15 deg. F.
occurred on the 17th, a maximum of 72 deg. on the 19th; in December a
maximum of 66 deg. on the 3rd, a minimum of 2 deg. on the 16th; in January a
minimum of 8 deg. on the 17th, a maximum of 74 deg. on the 27th; in February a
minimum of 11 deg. on the 2nd, a maximum of 72 deg. on the 25th; in March a
minimum of 8 deg. on the 10th, a maximum of 81 deg. on the 16th.
The extremes of temperatures in any one of these months may have been
sufficient to cause damage to chestnut, although the extent of damage is
influenced by the physiological conditions within the tree. The usual
type of injury to the hybrids was a killing of the cambial cells
extending from the base of the trunk up to varying heights. The cambial
region was grayish-black and the inner bark was sappy and
greenish-brown. More trees were injured and killed on the lower portions
of the plot than on the higher portions.
This catastrophe afforded opportunity to study resistance of the hybrids
to freezing. In the lower part of the plot there were several 3-year-old
American chestnut seedlings that were not damaged. Sixteen per cent of
first generation hybrids of Chinese and American chestnut were killed.
Chinese by American backcrossed with Chinese were killed to the extent
of 36 per cent. Chinese by Japanese chestnut of the second generation
were killed to the extent of 35 per cent.
Despite this extensive killing of hybrids by extreme variations of
winter temperatures, older Chinese and Japanese chestnuts on slightly
higher ground in the same plot suffered no visible injury. These old
trees have rough bark, which may serve as an effective insulator against
extremes of temperature. In 1944, there was no damaging late spring
frost, and these old trees produced the largest nut crop in their
history.
Winter temperatures of -25 deg. F. or lower are usually injurious to
Oriental chestnuts. A few reports of chestnuts surviving temperatures of
-25 deg. F. have been recorded, but usually Oriental chestnuts do not thrive
in those northern States or regions where such temperatures occur.
Many of our cooperators report that late spring frosts frequently cause
failure of chestnut crops. Damaging frosts in late spring occur more
frequently and over greater areas than early fall frosts or extreme
winter temperature variations. A late spring frost in 1945 reduced the
chestnut crop at Glenn Dale, Md., from 50 bushels expected to 3 bushels
actual. A freeze of 24 deg.F. on the nights of April 4 and 5 was sufficient
to inflict this damage after two weeks of abnormally warm weather. Many
of the trees were visibly injured, with wilted or dried unfolding buds.
Other trees on higher ground were not visibly affected, yet they
produced no crops.
Again it was noted that the American chestnut, followed by American
chestnut hybrids, sustained none to little damage. The American
chestnut, besides its inherent resistance to freezing, leafs late in
the spring. Most of the crop of nuts obtained in 1945 was produced by
the American chestnut hybrids.
Late spring frosts in 1945 were very extensive, reaching throughout the
eastern and northeastern States, and there were practically no chestnut
crops. There were also numerous reports of late spring frost injury to
chestnut in the Central States.
In order to reduce freezing injury to Oriental chestnuts, it is
essential that they be grown on sites that have excellent cold air
drainage. As an approximate rule, these chestnuts should be planted on
sites similar to those that are best for peaches. The orchard planting
is not the only type that is subject to winter injury; forest plantings,
ornamental plantings, and plantings for wildlife are also subject to
winter injury especially if they are not on the most favorable sites.