. 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, Tenness
|