Treesearch

It is well established that silvicultural thinning can increase tree growth and wood volume utilization in hardwoodstands, but the effects on tree quality and value are less clear. This study measured the effect of silvicultural thinning on tree grades over a period of 12 to 15 years for 803 black cherries (Prunus serotina, Ehrh.), 424 northern red oaks (Quercus rubra, L.), 180 red maples (Acer rubrum, L.), 235 trees in the white oak group (Q. spp.), and 494 yellow-poplars (Liriodendron tulipifera, L.). Grade distributions of trees >9.6 and > 12.6 in. diameter at breast height (DBH) for...

Increased use of character-marks, or naturally occurring features of wood such as knots, in wood household furniture has received attention recently as a means for U.S. furniture manufacturers to make more efficient use of forest resources. However, little information exists concerning furniture retailers' perceptions of character-marked wood. Propositions that predicted retailer response to character-marked furniture based on categorization theory were developed and tested using oak furniture samples. Conjoint analysis indicated that the preference structure for character-marks was...

Wherever and whenever forests and humans have occupied the same space on Earth, it can be expected that Non-Timber Forest Products (NTFP) have made important contributions to people's livelihoods. NTFP research and policy, however, have generally focused on the Third World. This special issue shifts attention to NTFP use, research, and policy concerns in the United States as a way of illustrating the important contribution of these products to post-industrial societies.

Assessments of urban farests in the United States reveal that there are currently 3.8 billion trees in urban areas with a compensatory value of $2.4 trillion.

Numerous anthropogenic factors can deplete calcium (Ca) from forest ecosystems. Because an adequate supply of Ca is needed to support fundamental biological functions, including cell membrane stability and stress response, the potential for Ca deficiency following the individual, cumulative, or potentially synergistic, influences of anthropogenic factors raises important questions concerning organism and ecosystem health. Past work has shown that one Ca-depleting factor (foliar acid mist exposure) reduces concentrations of biologically important membrane-associated Ca (mCa) from red spruce...

Long- and short-term effects of urban site factors on net N-mineralization and nitrification rates were investigated in oak stands along an urban-rural land-use transect in the New York City metropolitan area. We used reciprocal transplants of undisturbed soil cores between urban and rural forests to determine the relative importance of long-term effects (mor vs. mull soils, quality of soil organic matter, and deposition of N) vs. shortterm effects (soil temperature) of urban factors in controlling field N-transformation rates along the gradient. In addition, undisturbed soil cores from...

Several line- and point-based sampling methods can be employed to estimate the aggregate dimensions of trees standing on a forested tract or pieces of coarse woody debris lying on the forest floor. Line methods include line intersect sampling, horizontal line sampling, and transect relascope sampling; point methods include variable- and fixed-radius plot sampling, and point relascope sampling. We demonstrate that the line methods can be interpreted as applications of importance sampling and that point methods can be interpreted as two-stage applications of importance sampling and crude...

The rotated-sigmoid form is a characteristic of old-growth, uneven-aged forest stands caused by past disturbances such as cutting, fire, disease, and insect attacks. The diameter frequency distribution of the rotated-sigmoid form is bimodal with the second rounded peak in the midsized classes, rather than a smooth, steeply descending, monotonic curve. In this study a finite mixture of two Weibull distributions is used to describe the diameter distributions of the rotated-sigmoid, uneven-aged forest stands. Four example stands are selected to demonstrate model fitting and comparison....

Modeling ground-based timber harvesting systems with an object-oriented methodology was investigated. Object-oriented modeling and design promote a better understanding of requirements, cleaner designs, and better maintainability of the harvesting simulation system. The model developed simulates chainsaw felling, drive-to-tree feller-buncher, swing-to-tree single-grip harvester performing felling, and grapple skidder and forwarder in extraction activities. The model can be used to generate stands of trees, simulate felling and extraction processes, and analyze results in terms of cost and...

There are at least 44 exotic species of Scolytidae established in North America north of Mexico, of which 16 species can be found in the Great Lakes region (see Table). Scolytids occupy many niches, but the two most common groups are the true bark beetles and the ambrosia beetles (Poland and Haack 1998). Adult bark beetles, as their name implies, construct galleries under the bark of woody plants. Eggs are laid in niches along the gallery walls. The larvae feed primarily on the inner bark (phloem)tissue, then pupate, and emerge as adults. Ambrosia beetles typically tunnel into the wood...