Treesearch

We used the eddy-correlation technique to investigate the exchange of C02 between an undisturbed old-growth forest and the atmosphere at a remote Southern Hemisphere site on 15 d between 1989 and 1990. Our goal was to determine how environmental factors regulate ecosystem CO2 exchange, and to test whether present knowledge of leaf-level processes was sufficient to understand ecosystem-level exchange.

Uneven-aged silvicultural practices can be used to regenerate and manage many eastern hardwood stands. Single-tree selection methods are feasible in stands where a desirable shade-tolerant commercial species can be regenerated following periodic harvests. A variety of partial cutting practices, including single-tree selection and diameter-limit cutting have been used for 30 years or more to manage central Appalachian hardwoods on the Fernow Experimental Forest near Parsons, West Virginia. Results from these research areas are presented to help forest managers evaluate financial aspects of...

Presents allometric estimators relating aboveground and belowground component weights to diameter measurements of more than 2,500 trees and shrubs encompassing 35 woody species samples from 8 soil series. The estimators were only weakly related to soil character but were strongly influenced by population density variation induced by silvicultural treatment.

"Is Bambi Hogging The Forest?" This headline from a January 1993 article in the Washington Post gets to the heart of scientists' concern that browsing by an overabundance of whitetail deer is inhibiting forest growth and reducing the diversity of plant and animal species. The article cites an excessive deer population in Virginia (" ... probably five times as large as it was when European settlers arrived."), but in fact the problem extends throughout the eastern temperate hardwood forests from southern New England through the mid-Atlantic states and westward to the Great Lakes region.

Two recent essays by noted ecologists Daniel Botkin and Jared Diamond throw light on certain issues in natural resource conservation today. Botkin (1992), in A Natural Myth, relates his experience with the Hutcheson Memorial Forest, an oak forest reserve on the New Jersey Piedmont. The forest had been set aside with private funds in the 1950s to preserve the "state of harmonious balance" that would perpetuate itself for centuries if left undisturbed. Within two decades, however, it became obvious that the oaks were not regenerating and a dense maple understory had developed. So much for...

Depredation on artificial ground and cup nests in even-aged seedling/sapling, pole, and mature stands of continuous northern hardwood forest was studied in the White Mountain National Forest in New Hampshire, USA from May to June 1988. Track-board nests were used to identify predators of ground nests; plain ground nests and cup nests were used to investigate the effects of timber sizeclass on rates of predation. No elevation in nest predation rate was observed in the early stages of growth, nor was predation rate related to stand area. As elevated predation rates are usually taken to...

A whole-watershed manipulation project was begun on the Fernow Experimental Forest in West Virginia, USA, in 1987, with the objective of increasing understanding of the effects of acidic deposition on forest ecosystems. Two treatment watersheds (WS9 and WS3) and one control watershed (WS4) were included. Treatments were twice-ambient N and S deposition, applied via NH4S04 fertilizer, with three applications per year. Three years of pretreatment data were collected and used for calibration. Stream water chemistry data collected during 3 years of treatment were evaluated. Stream water pH and...