Treesearch

There have always been concerns about the impact of timber harvesting with conventional ground-based harvesting equipment on many parts of the forest ecosystem. One of these parts, which is easily measured, is the residual stand. The interest in small tractors (less than 60 horsepower) has increased in recent years because private landowners are concerned that large harvesting equipment may damage their woodlot. Several of these small tractors in the 12- to 60-horsepower range have entered the marketplace. We report on residual stand damage following thinning operations in northern...

Regression analyses were used to identify factors most closely related to species growth and mortality on continuous forest survey plots in Pennsylvania. In 1985, 200 plots with two prior measurements (in the 1960s and 1970s) were selected and measured for a third time to determine periodic forest growth and mortality rates. Growth and mortality were analyzed for temporal change and for relationship to site, stand, defoliation, and climatic factors and to wet atmospheric deposition. While basal area growth increased over the two intersurvey periods, growth rates declined and mortality...

A simple and fast method for extraction of major inorganic ions (Ca, Mg, Mn, K, and P) and cellular polyamines from small quantities of wood and woody plant tissues is described. The method involves repeated freezing and thawing of samples instead of homogenization or wet ash digestion. The efficiency of extraction of both polyamines and inorganic ions by these methods was compared for 10 different tissues. Drillbit shavings generated from wood disks or increment cores were also compared with ground wood as the starting material for ion analysis by this newly developed method of freeze-thaw...

Provides current and historical information on primary and secondary hardwood product production, prices, international trade, and employment.

Provides current and historical information on primary and secondary hardwood product production, prices, international trade, and employment.

I am flattered that Hetherington, Daniel, and Brown (1994) took the time to respond to a prepublication version of my article in the form of a commentary piece. They have raised a number of interesting and relevant issues and, despite their criticism of methodological pluralism, they have provided an example of one limited approach to methdological pluralism (critical multiplism). In the short amount of space available for my reply, I am unable to respond to every point raised. Instead, I will focus on the fundamental differences between the approach to studying environmental values that...

Does forest land subject to intensive outbreaks of gypsy moth (Lymantria dispar L.) become less susceptible to defoliation? A model for estimating the likelihood of gypsy moth defoliation has been developed and validated. It was applied to forest-inventory plot data to quantify trends in the susceptibility of forest land in south-central Pennsylvania during a period of intensive infestation. Results show that even though susceptibility of the region's forest apparently has deciined, the potential for future infestations remains relatively high.

Closure of logging wounds on 96 sample trees was evaluated after 2, 5, and 10 years for Appalachian hardwood trees in north-central West Virginia. For yellow-poplar, northern red oak, black cherry, and white oak, many small wounds, 1 to 50 square inches in size, closed between 5 and 10 years after logging. For larger wounds, 50 to 200 square inches, it appears that many of these wounds may not close for at least 15 or perhaps 20 years after logging. Recommendations are provided to minimize logging wounds on residual trees in partially cut stands.

A study was conducted in northern Pennsylvania to determine whether predation by small mammals and insects is related to the size of red oak acorns. Three sizes of acorns were used aiong with two planting techniques and three levels of overstory shading. Three-year results indicated that acorn size is not a factor in mammal and insect predation. Acorn size did not affect 3-year survival. Although 3-year total height growth was statisticaliy different after 3 years, the differences were too small for practical use.