In 1941 and 1942, over 4,000 untreated chestnut seeds, representing 22 strains, were planted in 12 locations in eight eastern States. The seed source was entirely from American-grown, Asiatic chestnut trees growing in 28 locations in 16 eastern States. They represented Chinese, Japanese, hybrids, and also a limited quantity of American chestnut seed. Seed of the American species was included primarily to determine whether or not it differs from the Asiatic species with reference to establishment by direct seeding. The results for the two years confirmed our earlier beliefs: Only 2.2 per cent in 1941, and 4.0 per cent in 1942, developed into seedlings, of which only a remnant have survived. No species or strain differences were apparent.
"Tin Can" Method
In 1944, the tin-can method was employed in planting 400 nuts in four eastern States. By this method 15.5 per cent of the planted nuts developed into seedlings, representing a fourfold increase over results obtained for the three previous years. One end of a No. 2 can is removed, and a cross is cut in the other end with a heavy-bladed knife. The open end of the can is then forced into the ground, over the planted nut, so that the top lies flush with the ground level. The four corners at the center of the cut top then are turned slightly upward, to allow a small opening through which the hypocotyl of the developing seedling can emerge. The can completely disintegrates by rusting within two or three years, and does not interfere with the seedling's development.
An examination made of the various burrows about the tin cans, and also of the teeth marks on fragments of chestnut seedcoats lying about, indicated that not only squirrels, but other rodents, such as chipmunks, field mice, moles, and even woodchucks were probably involved in the direct seeding failures.
In 1945 and 1946, the tin-can method was tested widely on farms, to determine its possibilities in securing establishment of blight-resistant chestnuts without a great outlay of cash to farmers. In 1945, five seeds were distributed to each of 90 cooperators residing in the Piedmont and southern Appalachian regions, and in the lower Mississippi and Ohio River valleys; and in 1946, to 38 cooperators residing in the Middle Atlantic States. Preliminary results indicate that 40.0 and 37.2 per cent of the nuts planted by the farmers developed into seedlings. It should be pointed out that these results are not strictly comparable with those of previous years, because most of the farmers preferred to plant the chestnuts in their gardens, and under these conditions the nuts were not exposed to the severe competition and the extreme rodent hazards that occur in the forests.
Further proof of the superiority of planting seedling stock over direct seeding as a method of establishment is indicated in the results of an experiment initiated in 1939. One hundred and fifty 1-year-old seedlings and 150 nuts, all of the same Chinese strain, were planted on cleared forest lands in the Coastal Plains, the Piedmont, and the southern Appalachian regions, and in the Middle West. At the end of the eighth year, at each location, establishment and development of those originating from the 1-year-old transplants were better than those originating from seed, and their average survival was six times greater.
Distribution of Planting Stock
During the period 1930 to 1946, the Division of Forest Pathology distributed thousands of Asiatic chestnut seedlings to Federal, State, and private agencies for experimental forest plantings in 32 eastern States. The ten States receiving the most planting stock, in the order named were: North Carolina, Tennessee, New York, Pennsylvania, West Virginia, Virginia, Ohio, Georgia, South Carolina, and Maryland. The purpose of this seedling distribution was to obtain information concerning the little-known characteristics of the Asiatic chestnuts—their soil and climatic requirements, and their range adaptability.
Selection of Planting Sites
At first the selection of the planting sites was left entirely to the judgment of the cooperators, and most of them assumed that the Asiatic chestnuts have site requirements similar to those of the native American chestnut. Because the American chestnut often occurs on dry ridges and upper slopes, especially where soil is thin and rock outcrops are frequent, the cooperators proceeded to plant the Asiatic chestnuts on similar "tough" sites. They believed that the planting of forest-tree species is justified only on defrosted areas that have reverted to grassland, or worn-out, unproductive agricultural land, or on wastelands—sites that we now know are better suited to the growing of conifers rather than hardwoods. As a result of this unfortunate choice of site selection, together with the several severe drought periods recurring in the early thirties, the cooperators lost most of their trees during the first and second years after planting.