Treesearch

A tree is a large, long-lived, perennial, compartmented, woody, shedding, walling plant. This definition is based on new tree biology concepts (Shigo, 1986a,b, 1991) and explains much about how mature trees function through their unique structure. When the tree begins its life, it is mostly leaf in mass (Fig. 7.la). As a tree grows in stature, it becomes mostly stem in mass and the foliage represents only a few percent of the total mass.

Traditional silvicultural practices focus on manipulating forest vegetation structure for commodity production. Structural features important to wildlife, such as snags, trees with decay, and cavity trees are also affected by forest management, but these effects are often not quantified. This study measured the effects of different thinning intensities (45, 60, and 75% residual relative densities and uncut controls), heartwood decay resistance (resistant, slight), and age (formed pre- or post-treatment) on the density and volume of snags and decayed wood in an Appalachian hardwood stand....

For many, concerns about the implications of "environmental change" conjure up scenarios of forest responses to global warming, enrichment of greenhouse gases, such as carbon dioxide and methane, and the northward migration of maladapted forests. From that perspective, the primary focus of this chapter, that is, causes of freezing injury to red spruce (Picea rubens Sarg.), may seem somewhat counterintuitive and inconsistent with the overall theme of the book. However, the dramatically increased incidence of freezing injury to northern montane red spruce forests over the past four decades...

Crown release of individual crop trees can be used to increase the growth and competitiveness of selected trees in young hardwood stands. Forest managers need information on the response of individual trees to such thinnings to prescribe stand treatments that meet specific management objectives. Codominant northern red oak (Quercus rubra L.), chestnut oak (Quercus prinus L.), black cherry (Prunus serotina Ehrh.), and yellow-poplar (Liriodendron tulipifera L.) crop trees in stands 12 to 16 yr old were given a crown-touching release by cutting all adjacent trees that touched the crown of a...

The southern United States produces over 50% of commercial timber harvests in the US and the demand for southern timber are likely to increase in the future. Global change is altering the physical and chemical environmental which will play a major role in determining future forest stand growth, insect and disease outbreaks, regeneration success, and distribution of species across the region.

Forestry may play an important if not critical role in the ability of the U.S. to meet its greenhouse gas emissions target under the terms of the Kyoto Protocol. Given the low rate of change in the U.S. forest land area, the major anthropogenic influences on the current net forest carbon flux are forest management and protection activities that have resulted in continuing increases in forest carbon storage. Natural disturbances such as fire, insects, and diseases are locally important factors, but when all U.S. forests are considered, they are small relative to the effects of harvesting...

The regeneration and dominance of northern red oak (Quercus rubra L.) has been associated with fire throughout eastern North America. Red oak in central Ontario grows near the northern edge of its distribution in mixed hardwood - coniferous forests under mesic conditions where it competes with more shade-tolerant species. We hypothesized that the abundance of red oak in these stands was largely the result of anthropogenic burning and natural fires, which would favor the regeneration and recruitment of northern red oak over such shade-tolerant species as sugar maple (Acer saccharum Marsh)....

Estimates of uncertainty are presented for projections of forest carbon inventory and average annual net carbon flux on private timberland in the US using the model FORCARB. Uncertainty in carbon inventory was approximately ±9% (2000 million metric tons) of the estimated median in the year 2000, rising to 11% (2800 million metric tons) in projection year 2040, with this range covering 95% of the distribution. Relative uncertainties about net flux were higher and more variable than relative uncertainty estimates of carbon inventory. Results indicated that relatively high correlations among...

This paper describes the late-successional and old-growth forest and the northern spotted owl effectiveness monitoring plans for the Northwest Forest Plan. The effectiveness monitoring plan for late-successional and old-growth forests will track changes in forest spatial distribution, and within-stand structure and composition, and it will predict future trends.

Four levels of precommercial thinning were applied with and without fertilization in a young, even-aged stand of northern conifers in east-central Maine. After 18 years, precommercial thinning resulted in longer and wider crowns and greater survival, growth, and yield of selected crop trees compared to untreated controls. Growth and yield were greater with uniform spacing at approximately 2.4 x 2.4 m and 1.5-m row thinning with crop-tree release in residual strips than with row thinning without crop-tree release. Control of stand species composition was greatest with uniform spacing....