Treesearch

Ten-year-old eastern white pine trees from southern Appalachian sources growing in southern Illinois and southern Indiana are taller and have fewer branches for their size than trees from other sources. In a northeastern Iowa plantation, the "best" seed source is not yet apparent.

Soil-pot tests with red oak seedlings indicated that forest soils supplied more N and P and produced better seedling growth than old-field soils. Growth was closely correlated with content of N and P in the foliage. K fertilization did not improve seedling growth on any of the soils studied.

Early results of a black walnut cornseed source study conducted in southern Illinois suggest that seed should be collected from local or south-of-local areas. Trees from southern sources grew faster and longer than trees from northern sources. Trees from southern sources flushed slightly earlier and held their leaves longer than trees from northern sources. For the 1969 season, height growth rate was best explained by the rainfall pattern. Diameter growth rate was more closely related to air and soil temperatures than to rainfall and soil moisture.

Reports a modified version of NCRETURN, a computer program for evauating forestry investments. The revised version, RETURN, provides additional information about each investment, including future net worths and benefit-cost ratios, with no added input.

Describes the use and contruction of an inexpensive temperature-gradient incubator.

Snow squall concentration in the Udell Hills of Michigan illustrates the effects of minor topographic features and the proximity of Lake Michigan on the seasonal distribution of precipitation. Application to water budget studies is indicated.

Basal-area growth, board-foot growth, and total board-foot production increase with residual stand densities ranging from 80 to 140 square feet per acre.

The potential damage of the Saratoga spittlebug to red pine can be predicted by comparing the percentage of ground occupied by sweet-fern with the percentage of ground cover occupied by other nymphal host plants. A risk-rating graph is used to estimate potential damage.

Complete crown release more than doubles the diameter growth of pole-size black walnut trees in southern Indiana over a 10-year period. Partially released trees gew about 50 percent more than unreleased trees. The faster growth of the released trees was directly related to increases in crown-area expansion. Most of the study trees produced bole sprouts; however, the incidence of sprouting was higher and the sprouts were larger on the completely released trees than on the unreleased trees. Controlling understory growth during the last 6 years of the study had no significant effect on growth...

Thinning 37-year-old aspen in north central Minnesota did not increase either total volume production or the number of veneer-sized trees after 10 years. Thinning is not recommended for stands nearing rotation age.