ince
ultimately nut trees require a great deal of space for best growth.
Walnut trees, for example, should be set 40 to 60 feet apart in each
direction.

[Illustration: _Pinus Flexilus nut seeds, Natural Size_]

I learned a variety of facts during these first years of trial and
error. I discovered, for instance, that iron fence posts rust away in an
acid soil; that one must use cedar or oak. Conversely, in alkaline soil,
iron will last indefinitely, but that the nitrogenous bacteria will
quickly rot wooden posts. I found that the secret of growing hickories
successfully lies in giving them plenty of room, with no forest trees
around to cut off their supply of sunlight and air. I learned that it is
impractical to graft a large forest tree of butternut or hickory.
Incidental to that, I learned that a branch of a butternut tree which
looks large enough to support a man's weight near the trunk, will not do
so when the branch is green and alive, but that a dead branch of similar
size will. Contrariwise, even a small green limb of a bitternut-hickory
will bear my weight, but an old limb, though several inches thick,
becomes so brittle after it is dead for several years that it will break
under slight pressure. Fortunately, falls from trees do not usually
result in serious injuries but I did acquire quite a few bruises
learning these distinctions.

There is always a natural mortality in planting trees, but in those
first years, lacking badly-needed experience, I lost more than 75%.
Nearly all of them started to grow but died during the first few
winters. Those which survived were the start of a nursery filled with
hardy trees which can endure the climate of the north. In looking back,
I appreciate how fortunate I was in having sought and received advice
from experienced nurserymen. Had I not done so, frequent failures would
surely have discouraged me. As it was, the successes I did have were an
incentive which made me persist and which left me with faith enough in
an ultimate success to go on buying seeds and trees and to make greater
and more varied experiments.

Chapter 3

BLACK WALNUTS

I have spent more of my time cultivating black walnuts than any other
kind of nut tree and given more of my ground area over to them. Yet it
was with no great amount of enthusiasm that I started working with these
trees. Obviously there could be nothing new or extraordinary resulting
from my planting trees of this species eit