Treesearch

Mountain pine beetle (Dendroctonus ponderosae Hopkins) has infested over 2 million acres of lodgepole pine (Pinus contorta Dougl. ex Loud.) forest since an outbreak began approximately in 2000 in north central Colorado. The tree mortality from mountain pine beetle outbreaks has the potential to alter stand composition and stand characteristics, along with fuel complexes. In general, it is assumed that these changes in stand structure from mountain pine beetle outbreaks in lodgepole pine forests increase fire hazard (Arno 1980, Jenkins and others 2008), though lodgepole pine fire regimes...

Many birds that are experiencing population declines require extensive tracts of mature forest habitat for breeding. Recent work suggests that at least some may shift their habitat use to early-successional areas after nesting but before migration. I used constant-effort mist netting in regenerating clearcuts (4-8 years postcut) and dense mature-forest understories to assess (1) whether most bird species of mature forests show habitat shifts after breeding; and (2), on the basis of several measures of condition, whether birds using early-successional habitats garnered any benefits or...

Throughout the Eastern United States, practitioners have primarily focused on using uniformly applied even-aged approaches to regenerate oak species. Irregular, gap-based silvicultural systems offer an alternative that retains continuous canopy cover, creates heterogeneous forest structure, and provides multiple income flows over a rotation. Although commonly used in Europe, there are few documented applications of these systems in oak forests of North America. Our objective is to establish a region-wide trial of two variants of an irregular group shelterwood system that successively...

In southeastern Oklahoma, loblolly pine (Pinus taeda L.) has been planted extensively outside the western boundary of its natural range. Furthermore, many plantings have been based on seed sources such as North Carolina Coastal (NCC) rather than Oklahoma-Arkansas (OA). NCC plantings are also frequent in nearby areas of Oklahoma and Arkansas which are within the loblolly pine natural range. A loblolly pine seed source and density trial planted in 1983 on Carter Mountain near Broken Bow, OK, provided the opportunity to compare individual tree characteristics of NCC vs. OA seed sources in a...

Restoring natural fire regimes and diverse ground cover to planted or old-field origin southern pine stands typically requires a substantial reduction in overstory density. While maintaining full canopy cover (CC) is consistent with maximizing fiber production, this approach does not allow sufficient light to reach the forest floor to accomplish a broader set of objectives. The relationship between stand basal area (BA) and CC has been used to regulate the overwood in shelterwood seed cuttings and is worth exploring for other purposes. Two factors potentially complicating the use of BA as...

We determined the effects of planting density (4- by 4-, 6- by 6-, 8- by 8-, and 10- by 10-foot spacing) on stand-level height, diameter at breast height, stem volume, basal area, and periodic annual increment for two loblolly pine (Pinus taeda L.) seed sources. Seed sources for the 25-year-old stands were a North Carolina seed source (NCC 8-01) and a regionally local Oklahoma/Arkansas seed source (O/A mix 4213). The research site was a droughty, mountain soil in southeastern Oklahoma outside the native range of loblolly pine. Except for subsoiling at planting, no other stand-level...

Wood specific gravity (SG) is one of the most important variables used to determine biomass. Measurement of SG is problematic because it requires tedious, and often difficult, sampling of wood from standing trees. Sampling is complicated because the SG usually varies nonrandomly within trees, resulting in systematic errors. Off-center pith and hollow or decayed stems pose further problems in biomass estimation. When the pattern of variation within a tree is known, as it often is for a given species, the sampling procedure can be greatly simplified by sampling wood that approximates a mean...

The second full annual inventory of Pennsylvania's forests reports a stable base of 16.7 million acres of forest land. Northern hardwoods and mixed-oak forest-type groups account for 54 and 32 percent of the forest land, respectively. The State's forest land averages about 61 dry tons of wood per acre and almost 6,500 board feet (International ¼-inch rule) per acre on timberland. The ratio of average annual net growth-to-removals for growing-stock trees on timberland was about 2:1. Additional information is presented on forest land use, forest resources, forest sustainability, forest...

Forests cover a vast area of the United States, 304 million ha or approximately one-third of the Nation’s land area (Smith and others 2009). These forests possess substantial ecological and socioeconomic importance. Both their ecological integrity and their continued capacity to provide goods and services are of concern in the face of a long list of threats, including insect and disease infestation, fragmentation, catastrophic fire, invasive species, and the effects of climate change.

Analyzing patterns of forest pest infestation, disease occurrences, forest declines, and related biotic stress factors is necessary to monitor the health of forested ecosystems and their potential impacts on forest structure, composition, biodiversity, and species distributions (Castello and others 1995). Introduced nonnative insects and diseases, in particular, can extensively damage the diversity, ecology, and economy of affected areas (Brockerhoff and others 2006, Mack and others 2000). Examining pest occurrences and related stress factors from a landscape-scale perspective is useful,...