Treesearch

Unfumigated hybrid poplars (Populus spp.) were compared with poplars of the same nine clones fumigated with 0.15 pprn ozone or 0.25 ppm sulfur dioxide. After 102 days, plant height and stem specific gravity were measured to determine whether specific gravity is altered by the fumigants and to compare that response to height suppression, an accepted measure of air pollution stress. Multivariate statistical analysis of the data for each clone revealed that the height of one clone and the stem specific gravities of six clones were suppressed by ozone. Specific gravity is an indicator of wood...

Manufacturers of turning squares have had difficulty finding the best combination of bolt and square sizes for producing squares most efficiently. A computer simulation technique has been developed for inexpensively detemining the best combination of bolt and square size. Ranges of bolt dimeters to achieve a stated level of yield are given. The manufacturer can choose which bolt sizes to use for sawing squares based on sawing method used, the range of bolt diameters available, and the size of square to be produced.

Regeneration surveys in fenced and unfenced portions of thirteen 9- to 22-year-old clearcuts on the Allegheny Plateauof Northwestern Pennsylvania show that deer browsing has resulted in (a) inadequate stocking of tree species, (b) delay in establishment, and (c) less valuable species composition. Ninety-two percent of the fenced areas, but only 38 percent of the unfenced areas, are considered satisfactorily stocked. The value of timber production lost as a result of browsing during the regeneration period is estimated to average $1,075 per acre.

Appalachian hardwood stands in West Virginia were studied to determine how reproduction establishment and development were influenced by circular clearcut openings of different sizes, postlogging herbicide treatments, and site quality. Ten-year results indicate that circular clearcuts should be at least 1/2 acre to gain the silvicultural effects of larger clearcuts. Smaller openings on both fair and good sites produced adequate numbers of trees, but diversity in species composition was lacking. Herbicide treatments reduced stump sprouting. After 10 years, 15 to 20 percent of the good...

Peach bark beetles, Phloeotribus liminaris (Harris), made abortive attacks on healthy black cherry, Prunus serotina Ehrh., trees. The beetle attacks caused five types of gum spots in the wood and a gummy exudate on the bark. The most extensive and common types of gum spot were single and multiple rows of interray gum spots that encircled the lower 3 m of the tree. Three to four attacks per 6.5 cm² of bark surface caused enough gum flow to produce a continuous ring of gum spot in the wood.

We examined 913 trees of 15 species in the vicinity of eight spring seeps in a second-growth maple-beech-birch forest. We found that 18 percent of the trees had large dead limbs that indicated top rot. We found 37 cavities in 27 trees (3.0 percent). However, only seven cavities were being used by wildlife in September and mice (Peromyscus sp.) used these as dens. The low density of cavities was not sufficient to maintain "fair" populations of cavity-nesting birds, and cutting trees to improve the seeps for wildlife would have little overall effect on cavity-using wildlife.

It has been suggested that on-site surveys of user fail to measure crowding accurately because long time users who knew the area before the "crowds" came tend to feel the most crowded, and thus do not return. Such "displaced" users would not be included in current on-site survey samples. Results from a limited test at the Sylvania Recreation Area in Michigan do not support this "displacement thesis." However, further research is needed in other settings to test this hypothesis more fully.

Discusses 1979 production and receipts and recent production for other years in the Lake and Central States. Shows Michigan, Minnesota, and Wisconsin production by species for each county and compares production by Forest Inventory Unit with that of previous years. Presents 1979 production and receipts data for Illinois, Indiana, Iowa, and Missouri, and shows four production classes by county.

Discusses recent Michigan forest industry trends, timber removals for industrial roundwood in 1977, and production and receipts of pulpwood, saw logs, and other industrial roundwood products. Reports on associated logging and primary mill residues and the disposition of mill residue.

A root observation chamber designed for forest nursery stock is described. The chamber consists of lower root observation section and a detachable upper "planter" section, both constructed of plexiglass and wood; the lower section is internally irrigated by a porous irrigation tube and the upper section by a "leader tube."