Experiment Station Record, Volume 92, January-June, 1945 Page: 60
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60 EXPERIMENT STATION RECORD [Vol. 92
growing characteristics of the southern stock was, offset by its lack of winter hardiness
when grown in the north.
Genotypic variation in white ash, J. W. WRIGHT (Jour. Forestry, 42 (1944),
No. 7, pp. 489-495).-Observations on young plants grown from seeds obtained
from 28 localities in United States and Canada and sown in a nursery in the Harvard
Forest, Petersham, Mass., showed the presence of at least three ecotypes. The
northern ecotype from Pennsylvania to Michigan, New England, and northward
had diploid, 2n = 46, chromosomes. These seedlings were resistant to winter injury
in their first year. The southern and intermediate ecotypes contained a diversity of
chromosome numbers, diploids; tetraploids, and hexaploids, and plants from southern
seed were subject to severe winter injury. The intermediate ecotype, from the
region of southern Pennsylvania and Ohio, suffered moderate winter injury. There
is indicated the need of using northern-produced seed for northern plantings, and
probably local seed would be desirable also in the southern region.
Chemical composition of leaves in different parts of sugar maple trees, E. F.
WALLIHAN. (Cornell Univ.). (.Jour. Forestry, 42 (1944), No. 9, p. 684).-In
late August 1941 three sugar maples of 50-, 42-, and 42-ft. heights were cut in
the Arnot Forest, N. Y. Leaf samples collected from the three trees were analyzed,
and the results showed small but real differences between basal and tip leaves on
a given twig with respect to percentage nitrogen and potassium contents. Leaves
from the tops of the trees contained slightly lower percentages of nitrogen than
did other leaves.
The most variable element was calcium, but no consistent trends were indicated.
The data suggest that a random sample of 50 to 100 leaves from the most accessible
part of a tree would constitute a representative sample.
Growth response in sugar maple following light selective cutting, W. M.
ZrLLIGITT. (U. S. D. A.). (Jour. Forestry, 42 (1944), No. 9, p. 680).-Light
selective cutting in a stand of sugar maple ranging from 10 to 23 in. d. b. h. and
located in an experimental forest near Dukes, Mich., accelerated growth but did
not change the form of the trees. The latter fact means that diameter measurements
are a satisfactory index to growth and will give a reliable picture of performance
Cutting cycles in ponderosa pine, G. A. PEARSON. (U. S. D. A.). (Jour.
Forestry, 42 (1944), No. 8, pp. 575-585, illus. 7).-A study of records taken on
five large sample plats logged 30 or more years ago and measured periodically since
that time showed that the rate of net increment rose during the first 10 yr. after
cutting and then declined so that in the third decade a level about 50 percent below
that attained in the first decade was reached. When the trees that were 12 in. or
above in diameter at the beginning of the record were separated from those that
subsequently attained the 12-in. class, the decline of the former group was still
greater. Mortality was only one of several contributing factors, with weakening
by mistletoe, squirrel defoliation, and lightning injury important. Overstocking was
also a cause. More frequent improvement cuttings appeared desirable.
Conservation rides timber trail in Turtle Mountains, W. H. PAUL and E. L.
WORTHINGTON (U. S. Dept. Agr., Soil Conserv., 10 (1944), No. 1, pp. 13-15, illus.
5).-An account is presented of the organization and operation of a cooperative
association formed to handle and market woodland products in northern North
Observations on the visibility of a small smoke, H. D. BucE. (U. S. D. A.
coop. Univ. Calif.). (Jour. Forestry, 42 (1944), No. '6, pp. 426-434, ilhus. 5).Results
of observations on a large number of standard small smokes given off by a
smoke candle showed that under the best of conditions, namely, clear air, uniform
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U.S. Department of Agriculture. Agricultural Research Administration. Office of Experiment Stations. Experiment Station Record, Volume 92, January-June, 1945, book, 1947; Washington. (digital.library.unt.edu/ark:/67531/metadc5064/m1/73/: accessed February 21, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.