Treesearch

American elm trees, Ulmus americana L., in Milwaukee, Wisconsin, were sprayed with methoxychlor by helicopter or mist blower once each year for 3 years to control the smaller European elm bark beetle Scolytus multistriatus (Marsham). Twig crotches were collected from sprayed trees each year for bioassay. Methoxychlor residues persisted for at least 1 year. There were differences in beetle control between spray techniques, but these differences decreased as years of successive spraying increased, suggesting that methoxychlor residues accumulate on elms. Tree surveys were made each year to...

In parts of Pennsylvania, oak regeneration after harvest cutting or natural disturbances has been very poor. Studies on the Tuscarora State Forest suggest that the primary cause of natural regeneration failure may be a lack of viable acorns; on some sites acorn insects and rodents destroy nearly all acorns, even in good seed years. Artificial regeneration is not without difficulties either: rodents were able to reach direct-seeded acorns even through plastic protectors; and planted seedlings have been severely damaged by deer browsing.

Uncertainty and inadequate information for prediction hinder attempts to judge the chances for success on logging jobs. In this study, variation in the success of commercial logging jobs in the Northeast was examined to relate the kinds of conditions present to the chances of logging being most successful under those conditions. Respondents rated half of the sample logging jobs most suceessful; they agreed that these jobs were excellent business ventures compared to other recent logging jobs. Splitting the sample on key variables substantially improved our ability to explain success on...

The occurrence of red spruce, hemlock, beech, and sugar maple stands was related to habitat classified by substratum (generally C horizon or parent material), drainage, aspect, and elevation. Softwoods were found on rocky, outwashed, compacted, and poorly drained substrata; hardwoods were common on open glacial tills. Species was related to climate and apparent resistance of the substratum to weathering.

A FORTRAN IV computer program calculates, from a few field measurements, the volume of tree crowns. This volume is in layers of a specified thickness of trees or large shrubs. Each tree is assigned one of 15 solid forms, formed by using one of five side shapes (a circle, an ellipse, a neiloid, a triangle, or a parabolalike shape), and one of three bottom shapes (a circle, an ellipse, or a triangle). A test of the accuracy of this technique shows that it produces estimates within acceptable limits of error if the shape is carefully selected. The program sorts these volume data by layer...

Shows 1974 veneer-log production and receipts by species in the Lake States (Michigan, Minnesota, and Wisconsin) and in the Central States (Illinois, Indiana, Iowa, and Missouri). Comparisons are made with similar data for 1972. Includes tables showing veneer-log production and receipts (for selected years) since 1946 in the Lake States and since 1956 in the Central States.

Discusses 1974 pulpwood production and receipts and recent production trends in the Lake States and Central States. Gives pulpwood production in the Lake States by species for each county, and compares production by Forest Survey Unit with that of previous years. For the Central States, presents 1974 pulpwood production and receipt data by state, and shows four production classes by county.

Discusses recent Wisconsin forest industry trends; timber removals for industrial roundwood in 1973; production and receipts in 1973 of pulpwood, saw logs, veneer logs, and other industrial roundwood products. Shows trends in pulpwood and veneer log production and compares saw log production in 1967 and 1973. Discusses primary wood-using plant residue and its disposition.

In a nearly optimal cultural environment, Populus 'Tristis #1' grown for 3 years, planted at 9 by 9 inch spacing produced the equivalent of over 4 tons/acre/year of ovendry wood with specific gravity comparable to native aspen wood. Trees planted at wider spacings yielded less.

Seed crops of 19 species occurred at irregular intervals over a 26-year period but crop sizes of fall-maturing species were related to those of spring-maturing species.