Treesearch

Ash trees (Fraxinus spp.) in North America are being severely impacted by the invasive emerald ash borer (Agrilus planipennis Fairmaire) which was inadvertently introduced to the US in the 1990s from Asia. The emerald ash borer (EAB) is a phloem boring beetle which relies exclusively on ash trees to complete its life cycle. Larvae feed in the cambial tissue forming serpentine galleries that may girdle the tree, causing mortality in as little as two years. Although larval feeding is thought to be the cause of rapid tree mortality, the relationship between tree-level water stress and EAB...

Amidst the dead, dying, and deformed beech trees left in the wake of beech bark disease (BBD), we are fortunate to find beech trees that remain healthy even in heavily infested areas. In stands across several US states it has been reported that disease-free beech trees are often found in clusters, providing evidence that resistance could be a genetic trait. Trees located in close proximity are likely to be closely related - either clonally through root-sprouting or as full- or half-sib seedlings. BBD is initiated by feeding activities of the beech scale insect (Cryptococcus fagisuga...

Hundreds of cankers caused by Ceratocystis smalleyi are associated with hickory bark beetle-attacked bitternut hickory exhibiting rapid crown decline in the north-central and northeastern United States. Discolored sapwood colonized by the fungus commonly underlies the cankers. Field studies were conducted to test the hypothesis that C. smalleyi infections cause vascular system dysfunction in infected trees. Fifty C. smalleyi inoculations made at 1.8 to 3.8 m in height on stems of healthy bitternut hickory trees (13 to 28 cm in diameter at 1.4 m in height) resulted in extensive canker...

This publication focuses on the thought processes and considerations surrounding a risk management process for decision making on wildfires. The publication introduces a six element risk management cycle designed to encourage sound risk-informed decision making in accordance with Federal wildland fire policy, although the process is equally applicable to non-Federal fire managers and partners. The process describes the assessment and control of identified risks, the analysis of benefits and costs, and the risk decision at multiple scales. Decision makers can apply principles from this...

A 55-year-old red oak-sweetgum (Quercus spp.- Liquidambar styraciflua) stand on the Delta National Forest in western Mississippi was subjected to a combination of low thinning and improvement cutting in 1997. Special emphasis was placed on removing all red oaks infected with Inonotus hispidus, a canker decay fungus that causes severe degradation and cull. Stand-level growth during the 10 years since thinning has been minimal. Thinning significantly increased diameter growth of residual trees, especially red oaks, but has not yet produced a significant increase in stand-level quadratic mean...

Headwater streams drain more than 70 percent of the total watershed area in the United States. Understanding of carbon dynamics in the headwater systems is of particular relevance for developing best silvicultural practices to reduce carbon export. This study was conducted in a low-gradient, predominantly forested watershed located in the Gulf Coastal Plain region, to (1) investigate spatiotemporal dynamics of carbon concentrations in the headwaters, (2) assess the relationships among stream carbon and nutrient conditions, and (3) quantify carbon export from the entire watershed. Fifteen...

The effect of plantation design on resource utilization has not been adequately investigated in agroforestry plantations. An experiment was conducted near Booneville, AR, on a silt loam soil with a fragipan. Loblolly pine (Pinus taeda L.) trees were planted in 1994 in three designs: two rows (1.2 by 2.4 m) with a 7.3-m alley, four rows (1.2 by 2.4 m) with a 12.2-m alley, and a rectangular 1.2- by 2.4-m configuration. Each 0.4-ha design was replicated three times. Height and d.b.h. were measured for 6 consecutive years (2002 to 2007) in 0.047-ha plots. Tree height increased annually from...

The potential of hardwood silvopasture has yet to be realized in the Southeastern United States. The decommissioning of the Stauffer Nursery, Opelika, AL, provided the opportunity to intensively research hardwood silvopasture using various oak species. Average crown diameter ranged from 5.9 feet in white oak (Quercus alba) to 10.7 feet in Nuttall oak (Q. nuttallii Palmer). Nuttall oak trees had significantly larger diameters, greater heights, and clear stem lengths than any of the other measured species, while white oak trees have the lowest values. Willow oak (Q. phellos L.) and cherrybark...

Seven landscape scale communities were identified in the Pine Mountain region having a mixture of Appalachian, Piedmont, and Coastal Plain species. The diagnostic environmental variables included elevation, B-horizon depth, A-horizon silt, topographic relative moisture index, and A-horizon potassium (K).

We employed meta-analysis and information theory to synthesize findings reported in the literature on the effects of fuel treatments on subsequent fire intensity and severity. Data were compiled from 19 publications that reported observed fire responses from 62 treated versus untreated contrasts. Effect sizes varied widely and the most informative grouping of studies distinguished three vegetation types and three types of fuel treatment. The resultant meta-analytic model is highly significant (p