On the basis of the experience gained from the earlier, extensive
distribution of Asiatic chestnut planting stock, the Division of Forest
Pathology, during the years of 1936, 1938, and 1939, established 21
Asiatic chestnut climatic test plots on cleared forest lands in eight
eastern States on the most favorable sites obtainable. These plots, with
their isolation borders, aggregating slightly less than 32 acres, and
accommodating nearly 22,000 trees spaced 8 by 8 feet, occur from
northern Massachusetts, along the Alleghenies southward to the southern
Appalachians in southwestern North Carolina, and from the Atlantic
seaboard, in southeastern South Carolina through the Middle West to
southeastern Iowa. More than 20 strains are being tested at each place,
including Chinese, Japanese, Seguin, and Henry species, as well as
hybrids, and progeny of some of the oldest introduced chestnuts. Most of
the plots are fenced against livestock and deer.
Although the results from these plots are as yet entirely preliminary,
during the 8- to 11-year period of testing, valuable information has
already been obtained: (1) The range of the Asiatic chestnuts tested
does not coincide entirely with the range of the American chestnut or
the native chinkapins. All Asiatic chestnut species that have been
tested have failed at Orange, Massachusetts, where the American chestnut
grew in abundance. In southeastern South Carolina, where the several
species of native chinkapin thrive, some of them 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.