attaining a height of
20 feet, the Asiatic species have largely failed. On the other hand in
northern Indiana and southeastern Iowa, entirely outside the botanical
range of the American chestnut, a few Chinese strains have done
remarkably well. (2) The Chinese chestnuts have a much wider range
adaptability to site than the Japanese chestnuts; the latter are more
restricted to mild climate and appear to require somewhat better site
conditions. Of ten Chinese strains tested, only four can thus far be
recommended for future planting in the Middle West. One Chinese strain
that has thus far proven far superior to the others, in all the climatic
plots, was introduced by the Department of Agriculture as seed from
Nanking, China in 1924. (3) Poorly aerated soil is an important limiting
factor in all regions where the chestnuts were tested.

Establishment by Underplanting and Girdling

On the basis of the field experience gained from the wide distribution
of Asiatic chestnut planting stock and the information thus far obtained
from the climatic test plots, a new method of establishing Asiatic
chestnut under forest conditions was initiated in the spring of 1946,
and is now being tried on a limited scale. It consists of underplanting,
with chestnut seedlings, a fully stocked stand of hardwoods ranging from
4 to 8 inches in diameter breast height in which the predominant species
are yellow poplar, northern red oak, white ash, and sugar maples. All
overstory growth 5 feet and over in height is then girdled. As the
girdled overstory trees die, they gradually yield the site to the
planted chestnuts in transition that does not greatly disturb the
ecological conditions, particularly of the forest floor. Rapid
disintegration of the mantle of leafmold is prevented by the partial
shading, which the dead or dying overstory, girdled trees cast. At the
same time, the partial shading hinders the encroachment of the sprout
hardwoods and the other plant invaders (which would normally become
established if the planted area had been clear cut) until the chestnuts
have become fully established. Not only does this system provide the
best site conditions conducive to the development of forest-tree form in
the Asiatic chestnuts, in limited areas, but also under establishment
conditions that require a minimum amount of maintenance.

Summary

In general, Asiatic chestnuts, when grown for timber purposes, are best
adapted to northern slopes, abo