Treesearch

The catastrophic fires and tragic losses during the 2013 fire season have resulted in many discussions about fire management policies aimed at protecting communities and restoring fire-resilient forests from the growing incidence of severe wildfires. Forest Service scientist Alan Ager has been exploring how concepts in spatial ecology and operations research can be used to better prioritize fuel management and restoration projects and design landscape fuel treatment strategies. This work has yielded a new model and software program called the Landscape Treatment Designer (LTD) and a case...

Smoke from wildfires has adverse biological and social consequences, and various lines of evidence suggest that smoke from wildfires in the future may be more intense and widespread, demanding that methods be developed to address its effects on people, ecosystems, and the atmosphere. In this paper, we present the essential ingredients of a modeling system for projecting smoke consequences in a rapidly warming climate that is expected to change wildfire regimes significantly. We describe each component of the system, offer suggestions for the elements of a modeling agenda, and provide some...

Communicating the scientific knowledge generated by the Pacific Northwest Research Station is integral to our mission. The 2013 Science Accomplishments reports highlights the breadth of the station’s research, the relevance of our science findings, and the application of these findings. The photographs throughout the report showcase the region where we work and how science is done.

A recent series of bark beetle outbreaks in the Rocky Mountain region of the U.S. is the largest and most intense ever recorded. Factors contributing to tree mortality from bark beetles are complex, but include aspects of forest stand condition. Because stand conditions respond to forest management, evaluating bark beetle-caused tree mortality and changes in forest structural attributes in areas previously subjected to management not only improves mechanistic understanding of beetle-caused changes in forests, but also improves prediction of future bark beetle responses to management...

This report provides new cost estimates for carbon sequestration through afforestation in the United States. We extend existing studies of carbon sequestration costs in several important ways, while ensuring the transparency of our approach. We clearly identify all components of our cost estimates so that other researchers can reconstruct our results as well as use our data for other purposes. Our cost estimates have five distinguishing features: (1) we estimate costs for each county in the contiguous United States; (2) we include afforestation of rangeland, in addition to cropland and...

Humans have intuitively understood the value of trees to their physical and mental health since the beginning of recorded time. A scientist with the Pacific Northwest Research Station wondered if such a link could be scientifically validated. His research team took advantage of an infestation of emerald ash borer, an invasive pest that kills ash trees, to conduct a study that gets closer to a definitive connection between the loss of trees and increased human mortality. Researchers analyzed data on demographics, tree loss from the emerald ash borer, and human mortality from lower respirator...

Aboveground growth rates of seedlings of bunchberry (Cornus canadensis L.), oval-leaf blueberry (Vaccinium ovalifolium Sm.), salmonberry (Rubus spectabilis Pursh), devilsclub (Oplopanax horridus (Sm.) Miq.), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) were compared in a study of their responses to an artificial light gradient in an Oregon greenhouse and in a study of response to overstory and soil type in a field manipulation experiment in southeast Alaska. Seedlings of all five species were grown independently under nine intensities of light for 156 days, and their oven-dry...

Stem decays of living trees, known also as heart rots, are essential elements of wildlife habitat, especially for cavity-nesting birds and mammals. Stem decays are common features of old-growth forests of coastal Alaska, but are generally absent in young, managed forests. We offer several strategies for maintaining or restoring fungal stem decay in these managed forests that can be used to enhance specific types of wildlife habitat.

Carbon storage and flux estimates for the two national forests in Alaska are provided using inventory data from permanent plots established in 1995–2003 and remeasured in 2004–2010. Estimates of change are reported separately for growth, sapling recruitment, harvest, mortality, snag recruitment, salvage, snag falldown, and decay. Although overall aboveground carbon mass in live trees did not change in the Tongass National Forest, the Chugach National Forest showed a 4.5 percent increase. For the Tongass National Forest, results differed substantially for managed and unmanaged forest:...

The pathway of radial water movement in tree stems presents an unknown with respect to whole-tree hydraulics. Radial profiles have shown substantial axial sap flow in deeper layers of sapwood (that may lack direct connection to transpiring leaves), which suggests the existence of a radial pathway for water movement. Rays in tree stems include ray tracheids and/or ray parenchyma cells and may offer such a pathway for radial water transport. This study investigated relationships between radial hydraulic conductivity and ray anatomical and stem morphological characteristics in the stems of...