Some experimenting has been done and much speculation has been indulged
regarding the tap root. One writer disposes of the whole subject in this
manner:
"The cutting of the tap root in planting seedlings has been a question
for much discussion, many growers formerly holding that to cut it meant
to kill the tree. This has proved a mistake. It has been practically
demonstrated that the tree thrives better with the tap root cut if
properly done with a sharp instrument, making a clean cut. New growth is
thereby induced, the abundance of lateral roots feed the tree more
satisfactorily and the trees come into bearing from two to three years
earlier than would otherwise be the case."
[Illustration: A Well Planted Tree]
Before accepting this as final it would be well to make further inquiry.
The summers of western Oregon are practically rainless and when the
kernel in the formed shell is maturing unless there is irrigation a
distress call is sent down to the roots for moisture, if the weather is
very dry. The lateral roots cannot supply this dire need and if the main
pump is not working away down deep in the moist earth the kernel will
not fill well and may perish entirely. For this reason no fibre of the
tap root should be disturbed, but rather encouraged by a well auger
hole, bored before the tree is planted, down to the reservoir of
moisture that will not fail in the dryest season.
The moisture in a dry season as a rule is nearer the surface in the
valley than in the hills and gives a better filled nut. In a wet season,
when the ground everywhere is full of moisture, the hills may produce a
more abundant crop than the valley, but in the run of years it will
require more time to prove which is most valuable for walnut culture.
Trees grow in either place, but he who cuts the tap root in any soil
does so at the peril of his crop in dry seasons.
Of the taproot, Wm. M. Reece, of the firm of Epps, Reece & Tillmont,
Eugene, Oregon, writes:
"The peculiar climatic conditions of the Willamette Valley, which
at a certain season of the year becomes semi-arid, fully justifies
the statement that trees not having a tap root are annually checked
in their growth when irrigation is not used; while those that do
have a tap root, as do walnuts, continue to grow and thrive even in
the driest weather. The walnut should be planted, however, in soil
having a subsoil free from any hard substance that will permit the
tap root to grow downward into the strata of perpetual moisture.
"This has been most thoroughly demonstrated in our walnut orchard
this, the driest year in the memory of old settlers in the Valley.
"When the growth of our apple, cherry and peach trees ceased
because of the dry weather, our walnuts kept on growing as if
supplied by continuous rains. It is true that liberal cultivation
through the dry season will materially aid the growth of all kinds
of trees not having a tap root and is indispensable to the growth
of young walnut trees, trees that have not extended their tap root
down to perpetual moisture.
"Walnut trees, in the opinion of the writer, cease growing upward
when they cease growing downward; that is to say, when rock, shale
or impenetrable hardpan stops the growth of the tap root, the tree
has practically reached its height.
"Therefore, in planting a walnut grove, borings should be made to
test the depth of the soil and character of the subsoil.
"Unquestionably the best variety for this climate is the Franquette
and next the Mayette.
"Grafted trees are to be preferred to seedlings. Grafted trees bear
much sooner and the fruit is more uniform in size, though a
seedling that has attained the bearing age will produce as much
fruit as a grafted tree of the same age; this we have occasion to
observe from comparisons in our own orchard.
"We have trees 14 years old that bore 100 pounds at the age of 12
years and the product sold for 25c a pound for planting purposes.
"Those who had the misfortune to have the tender shoots of their
walnut trees killed by the unusual frost early last May, should not
be discouraged. Just examine the limbs now and you will find that
three or four more shoots grew out where the one was killed. This
makes more fruit buds for next year and the shortage of crop this
year will be more than made up next.
"The writer believes that walnut growing will prove to be the most
profitable industry in the Willamette Valley.
"WM. M. REECE."
It seems to be a characteristic of the walnut and hickory, and possibly
other nut trees, to send down a tap root deep into the earth to draw up
the distilled and purified moisture that has been refined and sweetened
in the lower depths. The older boys of the Middle Western states can
recall the time when they wandered through the woods in late winter
time, with a long pole or rail on their shoulders with which they
"pulled hickory root." The young sprout was "withed" around near one end
of the pole, then all hands put their shoulders under the long end and
with an "altogether, heave, oh," draw up a tap root 4, 6 and 8 feet
long. The lowest end was the choicest and sweetest. It was delicious and
in the division of a day's hunt some of these found their way to "his
best girl" at school.
Whether the water down in these lower depths possesses these qualities,
and that they are necessary to give the Oregon walnut its superiority is
yet a matter of speculation, but that these conditions exist is well
known and should have fullest consideration by the intelligent walnut
culturist.
[Illustration: _Tap Root of a Two-year-old Black Walnut showing how the
root grows down to permanent water level, thus insuring full crops
regardless of weather conditions_]
Cut of tap root of a 2-year-old American Black which grew in the lower
red hill land of Yamhill County. There is but one lateral root near the
surface and this was probably caused by the tap root striking harder
soil on its way down to permanent moisture level.
This tap root is 3 feet long and nearly 6 inches in circumference. It is
one of the best object lessons to be had in walnut culture in Oregon.
Though the Willamette Valley has practically four rainless months of
sunshine, irrigation is unnecessary. There is no other country
comparable to it. Its cool and dewy summer nights, together with its
great subterranean reservoir supplied by the winter rains, are the
reasons why its crops never fail and why its fruits fill "red, round and
luscious," and why the walnut has so persistently shown its preference
for this favored region.