took new
heart, lived and again flourished.

At another time, I transplanted several thousand Montana pines, about
thirty or forty of which came within the branch limits of a medium size
butternut tree. Within a year, these thirty or more trees had turned
brown and were completely dead, while those immediately outside the
branch area were dwarfed and not at all thrifty. The trees farther from
the butternut were unaffected and grew consistently well. A similar
condition, although not to the same degree, developed under a white oak
where more Mugho pines were growing. Another instance occurred when a
planting of several thousand Colorado blue spruce were lined out and
fell within the area affected by two butternut trees. The spruce were
all dead within a few months.

Many people have observed the detrimental effect of trees of the walnut
family on alfalfa, tomatoes and potatoes, resulting in wilting and
dying. It is the root systems of the walnut which are responsible for
this damage. Apparently, there is some chemical elaborated near the
surface of the roots, and sensitive plants, whose roots come in contact
with either roots or ground containing this factor, are injured and
sometimes killed by it. One must therefore be very cautious about
trusting these trees as protectors of many of the ornamental and garden
plants. I am certain, from my own observations, that their influence on
evergreens is strongly antagonistic.

On another basis is the association between catalpas and chestnut trees
growing adjacent to one another. Constructive symbiosis apparently
develops when a young chestnut tree is planted within the radius of the
root system of a catalpa. The latter very definitely influences the
chestnut tree to grow more vigorously than it otherwise would.

I have recorded my observations of these antagonisms and friendships
between trees and plants to show that they are a reality which should be
taken into consideration in grouping and transplanting. Such warnings
are infrequent because some people may mistake them as condemnations of
certain favorite trees. I do not intend them as such, for these plants
are often valuable and worthwhile. This ability which they have
developed through the many years of their existence is a guarantee of
the sturdiness and strength of their family and species, not at all a
quality to be condemned.

CONCLUSION

If I had written this book twenty years ago, I would have prophesie