Again it was noted that the American chestnut, followed by American chestnut hybrids, sustained none to little damage. The American chestnut, besides its inherent resistance to freezing, leafs late in the spring. Most of the crop of nuts obtained in 1945 was produced by the American chestnut hybrids.
Late spring frosts in 1945 were very extensive, reaching throughout the eastern and northeastern States, and there were practically no chestnut crops. There were also numerous reports of late spring frost injury to chestnut in the Central States.
In order to reduce freezing injury to Oriental chestnuts, it is essential that they be grown on sites that have excellent cold air drainage. As an approximate rule, these chestnuts should be planted on sites similar to those that are best for peaches. The orchard planting is not the only type that is subject to winter injury; forest plantings, ornamental plantings, and plantings for wildlife are also subject to winter injury especially if they are not on the most favorable sites.
Growing Chestnuts for Timber
By Jesse D. Diller Plant Industry Station, Beltsville, Maryland
Before the turn of the century, and even before chestnut blight had swept through our eastern forests, destroying one of our most valuable commercial timber trees, European and Asiatic chestnuts had been introduced. They made variable growth in the Gulf States, along the eastern seaboard from Florida to southern Maine, the southern half of Pennsylvania, southwestern Michigan, southeastern Iowa, down the Mississippi River Valley and on the Pacific Coast. These trees were grown for horticultural purposes, and for the most part, represented large-fruited varieties of Japanese chestnuts. They were not regarded as having forest-tree possibilities for in the open situations in which they were usually planted to insure early fruiting, the trees developed low-spreading crowns, resembling orchard trees. However, after the blight became fully established and it became apparent that our American chestnut was doomed, and that these scattered Asiatic chestnut trees had a natural resistance to this disease, a new interest developed in the Asiatic chestnuts as a possible substitute for the American chestnut.
The interest in and need for resistant, forest-type chestnuts became so great that the U. S. Department of Agriculture imported from the Orient seed of strains that might be suitable for the production of timber, poles and posts, with tannin and nuts as valuable by-products—qualities inherent in our native chestnut. The Division of Forest Pathology, Bureau of Plant Industry, Soils, and Agricultural Engineering has been carrying on the project of testing Asiatic chestnuts as timber trees. Professor R. Kent Beattie of this Division was in China, Korea, and Japan from 1927 to 1930, and collected over 250 bushels of seed for shipment to this Division. The seeds represented four species: Castanea mollissima—the Chinese chestnut; C. henryi—the Henry chinkapin; C. seguinii—the Seguin chestnut; and C. crenata—the Japanese chestnut.
Direct Seeding Studies
At the very beginning of these investigations in growing Asiatic chestnuts as timber trees, it was believed that greater success in establishment could be obtained by planting seedlings, rather than by direct seeding. In direct seeding trials during the early thirties the planted nuts were promptly devoured by rodents. Sixteen years of field experience has proven the soundness of this belief. The imported nuts were planted in the Division's nursery at Glenn Dale, Md., and the resulting seedlings distributed as 1- and 2-year-old trees to cooperators throughout the eastern United States.
In order to thoroughly test the possibilities of direct seeding as an economical method of establishment, this Division during seven years (1939 to 1942, and 1944 to 1946) planted over 7,000 nuts by direct seeding in 200 locations in 18 eastern States. It was suspected that the greatest hazard to direct seeding in or near forests would be rodents. Accordingly, in the spring of 1939 and 1940, 400 nuts and 600 nuts, respectively, were coated with a strychnine-alkaloid rodent repellent, and a comparable number of seeds, for both years, were left untreated to serve as checks. The checks were held in sphagnum moss at Beltsville, Md., and the nuts to be treated were packed in sphagnum moss and expressed to Denver for treatment by the Division of Wildlife Research, the Fish and Wildlife Service, Department of the Interior. Only 5.9 and 2.5 per cent of the treated seeds developed into seedlings, whereas 22.6 and 13.5 per cent of the untreated seeds produced seedlings. Not only did more of the treated seeds fail to germinate than of the untreated seeds, but the seedlings from the treated nuts were less vigorous. Because of the results obtained, the rodent-repellent study was discontinued at the end of the second year.