Treesearch

Multi-temporal satellite imagery can provide valuable information on the patterns of vegetation growth over large spatial extents and long time periods, but corresponding ground-referenced biomass information is often difficult to acquire, especially at an annual scale. In this study, we test the relationship between annual biomass estimated using shrub growth rings and metrics of seasonal growth derived from Moderate Resolution Imaging Spectroradiometer (MODIS) spectral vegetation indices (SVIs) for a small area of southern California chaparral to evaluate the potential for mapping...

In 2013, while surveying for five-needle white pine cone crops in northeastern Nevada, we observed white pine blister rust, caused by the rust pathogen Cronartium ribicola Fisch., infecting branches and stems of limber pines (Pinus flexilis James) on Pine Mountain (41.76975°N, 115.61622°W), Humboldt National Forest, Elko County, Nevada. Nearby whitebark pines (P. albicaulis Engelm.) were also infected. Pine Mountain rises to 2,636 m, is sparsely forested, and is located 11.25 km west of the Jarbidge Mountains, where infection by blister rust on whitebark pine was first reported at Coon...

A recently developed detached-leaf blight resistance assay has generated interest because it could reduce the amount of time needed to evaluate backcrossed hybrid trees in the American chestnut blight resistance breeding programme. We evaluated the leaf inoculation technique on a sample of advanced progeny from the Indiana state chapter American Chestnut Foundation breeding programme, along with susceptible American chestnut (Castanea dentata), the recurrent parent, and resistant Chinese chestnut (Castanea mollissima), the donor parent for blight resistance. In experiments over 2 years...

Climate change has the potential to significantly impact the stability of large stocks of mercury (Hg) stored in peatland systems due to increasing temperatures, altered water table regimes and subsequent shifts in vascular plant communities. However, the Hg exchange dynamics between the atmosphere and peatlands are not well understood. At the PEATcosm Mesocosm Facility in Houghton, Michigan, total gaseous Hg (TGM) fluxes were monitored in a subset of 1-m3 peat monoliths with altered water table positions (high and low) and vascular plant functional groups (sedge only, Ericaceae only or...

Widespread tree mortality from mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) outbreaks has prompted forest management activities to reduce crown fire hazard in the Rocky Mountain region. However, little is known about how beetle-related salvage logging and biomass utilization options affect woody surface fuel loads and fuel moisture dynamics. We compared these attributes in salvage-logged lodgepole pine (Pinus contorta var. latifolia Engelm. Ex S. Wats.) stands harvested using either biomass removal (whole-tree harvest) or biomass retention (bole only harvest) prescriptions...

This resource update provides an overview of forest resources in east Texas based on an inventory conducted by the U.S. Forest Service, Forest Inventory and Analysis (FIA) program at the Southern Research Station (SRS) in cooperation with Texas A&M Forest Service. The 254 counties of Texas are consolidated into seven FIA survey units—Southeast (unit 1), Northeast (unit 2), North Central (unit 3), South (unit 4), West Central (unit 5), Northwest (unit 6), and West (unit 7). The estimates presented in this update are limited to east Texas, which is made up of units 1 and 2 with a total of 43...

Lurking below the twin concepts of connectivity and disconnectivity are their first, and in someways, richer cousins: continuity and discontinuity. In this paper we explore how continuity and discontinuity represent fundamental and complementary perspectives in fluvial geomorphology, and how these perspectives inform and underlie our conceptions of connectivity in landscapes and rivers. We examine the historical roots of continuum and discontinuum thinking, and how much of our understanding of geomorphology rests on contrasting views of continuity and discontinuity. By continuum thinking...

Pinus pungens (Table Mountain pine) stands are rare conifer-dominated communities that occur on xeric ridges and upper slopes throughout the central and southern Appalachian Mountains. At the northern end of this range, this uncommon forest community is essentially unstudied. Therefore, in 2006 I initiated a dendroecology study of three Pinus pungens stands growing in Pennsylvania to better understand their current conditions, histories, and likely future succession. These stands contained from four to 14 tree species with Pinus pungens or Quercus montana (chestnut oak) dominating the main...

Oak (Quercus spp.) research and management often focus on northern red oak (Quercus rubra) and assume that associated upland oaks have similar growth patterns. To test this premise, we measured the survival and development of four species of acorn-origin oak seedlings growing in four different levels of understory sunlight for 8 years. Northern red oak had better survival than black (Quercus velutina), chestnut (Quercus montana), and white oak (Quercus alba) in 5% sunlight, but none of the species exhibited much growth. In 15 and 40% sunlight, survival was equal among species, but for...

We conducted an experimental study of infection, transmission, and persistence of a nucleopolyhedrovirus (NPV) of Douglas-fir tussock moth (Orgyia pseudotsugata) to better understand mechanisms determining the efficacy of the virus when it is used as a microbial control agent. In a field experiment, we quantified infection rates of larvae exposed to either Tussock Moth Biocontrol-1, the strain currently used for control by the U.S. Forest Service, or a wild-type strain isolated from a natural population. We first allowed each pathogen to decay on experimental branches for 0, 1, or 3 days...