Treesearch

The diameter growth rate of pruned trees increased the second year after pruning, whereas the diameter growth of unpruned trees was not as fast during the second year. Diameter growth rate was positively correlated with the height to which all branches were pruned. After the pruning shock of the first year, trees pruned to 50 percent of their height showed the greatest cumulative growth in diameter.

Thirty-eight scarlet and 14 black oaks were spirally wrapped to a height of about 2 m with black or white cotton tape 2.5 cm wide in an attempt to increase oviposition of the red oak borer, Enaphalodes rufulus (Haldeman), on selected trap trees. However only 57 eggs were laid under tape on 17 of the trees, all scarlet oaks. Attacks but no eggs were found on some of the wrapped black oaks.

The loss of terminal buds on small balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea spp.) trees because of nipping by mammals or birds has increased on the Penobscot Experimental Forest in recent years. The cut stem is smooth and slightly angled; there is no sign of tearing. Unnipped trees grew about 13 percent more than the nipped trees; the nipped trees showed less vigor in the lateral bud that took over as leader.

A hydraulic locking mechanism was designed to replace the manual skyline lock on a small standing skyline with gravity carriage. It improved the efficiency of the operation by reducing setup and takedown times and reduced the hazard to the crew.

The disposal of human waste by composting at backcountry recreation areas is a possible alternative to methods that are considered unsafe. The literature indicates that aerobic, thermophilic composting is a reliable disposal method that can be low in cost and in maintenance. A bark-sewage mixture can be composted to produce a pathogen-free substance that might be used in site rehabilitation. Composting in a leakproof bin is odorless, and is largely independent of site conditions.

A current tactic for biological control of the gypsy moth, Lymantria dispar Linnaeus, is to release its parasites in forests susceptible to gypsy moth damage before the gypsy moth arrives. The basic assumption in these anticipatory releases is that the parasites can find and utilize native insects as hosts in the interim. Blepharipa pratensis is being used in this way. The efficacy of such releases has not been demonstrated. The present state of our knowledge about the niche requirements of gypsy moth parasites in general, and B. pratensis in particular, does not permit an evaluation now....

Studies on the Allegheny Plateau of Pennsylvania have shown that several types of wire or plastic tubes can be erected around tree seedlings to protect them from deer browsing. The two most promising devices are a 4- to 6-inch diameter plastic tube with small mesh and a 12-inch diameter tube constructed of chicken wire. Both types need to be at least 5 feet tall to provide adequate protection in areas of heavy browsing pressure. The plastic protectors are more expensive than those made of wire, but are somewhat quicker to fabricate, and they offer the added advantage of protection against...

Knowledge acquired from forests that have never been logged can provide clues to the long-term effects of resource utilization. In 1974, a survey was made of the vegetation of the Bowl Research Natural Area in central New Hampshire, known to be undisturbed by humans; and an adjacent watershed known to have been logged in the late 1880's. There were no significant differences in the mean basal areas and aboveground biomass of trees between the two watersheds, indicating that 90 years after logging this forest has nearly recovered. The major species in the Bowl are yellow birch, beech, sugar...

Black walnut and northern red oak seedlings were planted on a clearcut area in 1964. Three cultural treatments were applied to seedlings to control competing trees. Average height and survival were analyzed 13 growing seasons after planting. Results indicated that black walnut seedlings can be effectively established on good sites if cultural treatments are applied. Red oak seedlings are difficult to establish, regardless of treatment or site.

Laboratory studies have suggested the existence of a pheromone in the locust borer. Male beetles spent more time on bolts of wood exposed to virgin females than on control bolts. The females apparently deposited the pheromone on the bolts of wood and filter paper.