Treesearch

Production of American chestnut (Castanea dentata) resistant to the chestnut blight fungus (Cryphonectria parasitica) is being conducted currently through traditional breeding and genetic transformation. Sufficient material for field testing is currently available from The American Chestnut Foundation’s backcross breeding program. We planted approximately 4500 chestnut seedlings into forest test plantings on three National Forests over three years, beginning in 2009. Early survival and growth was dependent on disease pressure from exotic pathogens, primarily, root rot caused by Phytophthora...

Use of woody biomass from sustainably managed sources to produce energy is considered an important strategy to mitigate climate change because the resource is renewable (biomass regrowth on land recaptures emitted carbon dioxide (CO2) due to biomass burning) and can substitute for fossil-fuel-based energy such as coal and natural gas. However, consensus on the degree of contribution of woody biomass to climate change mitigation is lacking. The reason for this lack of consensus is that different analysts include different carbon (C) stock changes (e.g. C stock change where feedstock is...

Since its introduction in the 1860s, gypsy moth, Lymantria dispar (L.), has periodically defoliated large swaths of forest in the eastern United States. Prior research has suggested that the greatest costs and losses from these outbreaks accrue in residential areas, but these impacts have not been well quantified. We addressed this lacuna with a case study of Baltimore City. Using two urban tree inventories, we estimated potential costs and losses from a range of gypsy moth outbreak scenarios under different environmental and management conditions. We combined outbreak scenarios with urban...

The existence of thousands of soft-story woodframe buildings in California has been recognized as a disaster preparedness problem resulting in mitigation efforts throughout the state. The considerable presence of these large multi-family buildings in San Francisco prompted the city to mandate their retrofitting over the next seven years. The NEES-Soft project, whose full title is “Seismic Risk Reduction for Soft- Story Woodframe Buildings,” is a five-university multi-industry three-year project which has many facets including improved nonlinear numerical modeling, outreach, retrofit...

An inter-laboratory comparison of a UV-Vis spectroscopic method (TAPPI T 282 om-13 “Hexeneuronic acid content of chemical pulp”) for hexeneuronic acid measurements was conducted using three eucalyptus kraft pulps. The pulp samples were produced in a laboratory at kappa numbers of approximately 14, 20, and 35. The hexeneuronic acid contents of the three pulps were approximately 55–65 ìmol/g, or with a variation of approximately 15%. Five laboratories from four different countries participated in this round-robin study as part of the evaluation of the TAPPI provisional method for upgrading...

Fire has a profound, though paradoxical influence on landscapes of the southeastern U.S.; it simultaneously maintains native biodiversity and ecosystem processes but also threatens silvicultural resources and human landscapes. Furthermore, since the majority of the southern landscape is heavily influenced by human activities, contemporary fire regimes are human managed disturbances within extant firedependent ecosystems. Though there is considerable uncertainty in climate projections for the southeastern U.S., climate change will likely impact both prescribed fire and wildfire. In this...

As the focus of forest management on many public lands shifts away from timber production and extraction to habitat, restoration, and diversity-related objectives, it is important to understand the long-term effects that previous management activities have on structure and composition to better inform current management decisions. In this paper, we analyzed 40 years of growth data to quantify (1) the long-term response of yellow-poplar to thinning across an age and site quality gradient, and (2) the longevity of any growth response yellow-poplar may have to thinning throughout the southern...

Occluded, or intra-aggregate, soil organic matter (SOM) comprises a significant portion of the total C pool in forest soils and often has very long mean residence times (MRTs). However, occluded C characteristics vary widely among soils and the genesis and composition of the occluded organic matter pool are not well understood. This work sought to define the major controls on the composition and MRT of occluded SOM in western U.S. conifer forest soils with specific focus on the influence of soil mineral assemblage and aggregate stability.We sampled soils from a lithosequence of four parent...

The overall objective of this field study was to determine if Pinus nigra (Austrian Pine) could serve as a useful biomonitor to evaluate multi-year concentrations of total mercury (tHg) in vegetataion within southwesrern Pennsylvania. Austrian Pine has been widely planted as an ornamental and formerlay as a Christmas tree, and is now naturalized within the region. We collected needle samples annually during October 2004-2010 at 15-21 locations within a 5000-km2 study area. Because Austrian Pine trees typically retain needles for 3 years, we collected samples from 3 needle-age groups:...

1. Modelling the effects of environmental change on populations is a key challenge for ecologists, particularly as the pace of change increases. Currently, modelling efforts are limited by difficulties in establishing robust relationships between environmental drivers and population responses. 2. We developed an integrated capture–recapture state-space model to estimate the effects of two key environmental drivers (stream flow and temperature) on demographic rates (body growth, movement and survival) using a long-term (11 years), high-resolution (individually tagged, sampled seasonally)...