Treesearch

Wildland fire represents an important ecological mechanism in many forest ecosystems. It shapes the distributions of species, maintains the structure and function of fire-prone communities, and is a significant evolutionary force (Bond and Keeley 2005). At the same time, fire outside the historic range of frequency and intensity can have extensive economic and ecological impacts. Current fire regimes on more than half the forested area in the conterminous United States have been either moderately or significantly altered from historical regimes, potentially altering key ecosystem components...

Tree mortality is a natural process in all forest ecosystems. However, extremely high mortality also can be an indicator of forest health issues. On a regional scale, high mortality levels may indicate widespread insect or disease problems. High mortality may also occur if a large proportion of the forests in a region is made up of older, senescent stands.

This science update provides an overview of forest resource attributes for the Commonwealth of Kentucky based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) Program at the Southern Research Station of the United States Department of Agriculture Forest Service in cooperation with the Kentucky Department of Natural Resources Division of Forestry. These annual estimates, along with Web-posted supplemental tables, will be updated annually. For more information regarding past inventory reports for this State, inventory program information, field sampling methodology,...

At one time, the Lower Mississippi Alluvial Valley was covered by almost 25 million acres of forest. By the mid-1980s, all that remained of the valley’s forested land was roughly 6.6 million acres. This report addresses a gap in data about this land by providing, for the first time since 1986, comprehensive new estimates of forest area, volume, carbon, and tree species stocking change.

This science update provides an overview of forest resource attributes for the State of Tennessee based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) Program at the Southern Research Station of the United States Department of Agriculture Forest Service in cooperation with the Tennessee Department of Agriculture Division of Forestry. These annual estimates, along with Web-posted supplemental tables, will be updated annually. For more information regarding past inventory reports for this State, inventory program information, fi eld sampling methodology, and...

National-scale forest inventories have endeavoured to include holistic measurements of forest health inclusive of attributes such as downed dead wood and tree regeneration that occur in the forest understory. Inventories may require year-round measurement of inventory plots with some of these measurements being affected by seasonal obstructions (e.g. snowpacks and seasonal flooding). In order to assess the potential effects that snow/water obstructions may have on the measurement/analysis of forest seedlings across large scales, the differences in seedling abundance between two inventory...

Thousand cankers disease (TCD) is a growing threat to black walnut, an economically and ecologically important tree in the eastern US. Trees in the earliest stages of TCD do not display symptoms. In later stages, leaves of the canopy become yellow, wilt, and ultimately die, yet remain attached to their branches. Eventually, all branches in the canopy may die, leading to tree death. TCD is caused by the fungus, Geosmithia morbida that is carried by walnut twig beetles (Pityophthorus juglandis) attracted to walnut trees. After landing on a tree, the beetles bore into the inner bark to create...

Drought is a major environmental stress limiting growth of perennial grasses in temperate regions. Plant drought tolerance is a complex trait that is controlled by multiple genes. Candidate gene association mapping provides a powerful tool for dissection of complex traits. Candidate gene association mapping of drought tolerance traits was conducted in 192 diverse perennial ryegrass (Lolium perenne L.) accessions from 43 countries. The panel showed significant variations in leaf wilting, leaf water content, canopy and air temperature difference, and chlorophyll fluorescence under well-watere...

Traditionally, the main focus of forest production has usually been to maximize allocation of biomass to merchantable stem wood. But the assessment of biomass partitioning in stands is needed to address management concerns such as stem production and allocation, carbon sequestration, wildland fire, whole tree harvesting, etc. Thinning mainly increases the bole diameter and crown area of the residual trees. This change results in changes in biomass partitioning to tree components. To meet all purposes of forest management it is imperative to understand the effects of thinning on the...

Leaf biomass and its display within the canopy are important driving variables of stand growth because they reflect a tree or stand’s capacity to intercept radiation, reduce carbon dioxide, and transpire water. We determined the effects of planting density (4- by 4-, 6- by 6-, 8- by 8-, and 10- by 10-foot spacing) on annual needle fall biomass, intercepted radiation, and canopy openness and then related these measures of canopy size to current annual increment and basal area for 25-year-old stands planted with two loblolly pine (Pinus taeda L.) seed sources: North Carolina Coastal (NCC...