Treesearch

Aspect affects soil frost depth by influencing the amount of solar radiation received at the ground or snow surface. Depending on the conditions, frost can be of equal depth on north and south slopes, deeper on north slopes, or deeper on south slopes. Data illustrate all three conditions

Six-year results from two strips clearcut and broadcast burned in a peatland forest indicate that tamarack will be an important component in new stands on such areas if even a few seed-bearing tamaracks are within 3 chains.

The combined effects of various concentrations of N, P, and K on the growth of paper birch seedlings were tested in sand culture tests. All other elements were held constant. The best seedling growth and dry weight of foliage generally occurred at concentrations of 400 p.p.m. N, 50 p.p.m. P or 600 p.p.m. N, 75 p.p.m. P. The concentration of K had relatively little effect. The optimum combination was not found but the results suggested that the amount of K should be increased

Use of 1/10-acre square plots to obtain estimates of the proportion of never-weeviled trees necessary for evaluating and scheduling white-pine weevil control is described. The optimum number of trees to observe per plot is estimated from data obtained from sample plantations in the Northeast and a table is given. Of sample size required to achieve a standard error of the proportion of trees never weeviled of ± 0.05, a value that can be obtained at a reasonable cost for the purpose intended.

Virgin northern hardwoods in the Bowl, a natural area in the White Mountain National Forest in New Hampshire, exhibit a limited number of species, large sizes in all key species except beech, a full understory, and a well-developed diameter distribution.

This booklet outlines what happens most of the time as decay develops in a living tree. The drawings are designed to give an accurate general presentation of the decay process by focusing only on the major portions of an extremely complex process that involves the interactions among microorganisms, environmental factors, and the tree. The better we understand these processes the better we can prevent and control decay-the major cause of damage to all species of trees throughout the world.

This annotated list includes 87 cicadellid and 13 fulgorid entries that were found on and probably feed on elm to some extent. Thirteen of the cicadellid species listed are known vectors of virus or mycoplasmalike diseases of plants. Also, the following 18 cicadellid genera contain known vectors of virus or mycoplasmalike diseases of plants: Aceratagallia Kirk., Agallia Curtis, Agalliopsis Kirk., Chlorotettix VanD., Coelidia Germar, Colladonus Ball, Draeculacephala Ball, Empoasca Walsh, Endria Oman, Graphocephala VanD., Gyponana Ball, Idiodonus Ball, Keonolla Oman, Macrosteles Fieb.,...

The 17,000 acre McCormick tract, nestled in the Michigamme Highlands of Michigan`s Upper Peninsula, has rested quietly since the white pine loggers broke camp 70 years ago. The few occasional visitors have been hikers, fishermen, hunters, and trappers, who left little imprint on the land. The roads that eventually dissected the surrounding area never penetrated here. This untrammeled and undeveloped condition makes the McCormick tract, willed to the U. S. Forest Service by Gordon McCormick in 1969, an especially valuable experimental forest.

Examines aspects of precipitation-hours per unit time. Presents nationwide patterns of mean precipitation-hours per month as well as precipitation-hours per precipitation-day.

In a 60-year-old northern hardwood stand treated with lime plus NPK fertilizer, the following increases in average basal area growth rate over untreated trees were observed: sugar maple 128 percent, paper birch 69 percent, yellow birch 51 percent, and beech 20 percent. Magnitude of response was inversely related to relative growth rate of the species. Growth rate before treatment was used as a covariate to adjust treatment means for differences in vigor of the trees.