Treesearch

Ponderosa pine and dry mixed-conifer forests in the Southwest United States are experiencing, or have become increasingly susceptible to, large-scale severe wildfire, insect, and disease episodes resulting in altered plant and animal demographics, reduced productivity and biodiversity, and impaired ecosystem processes and functions. We present a management framework based on a synthesis of science on forest ecology and management, reference conditions, and lessons learned during implementations of our restoration framework. Our framework focuses on the restoration of key elements similar...

Traumatic resin ducts form in xylem and phloem tissue of conifers in response to abiotic wounding, fungal invasion, and insect attack. Little is known about resin duct characteristics in the wood of fire-scarred trees. The aim of this study is to quantify changes in traits of both axial and radial resin ducts, along with those of associated epithelial cells and fusiform rays, in 2 individuals each of Larix occidentalis and Pseudotsuga menziesii. Transverse and tangential microsections were cut from samples for light microscopy. Using image analysis, anatomical measurements of cells are...

Fire scars are visible evidence of compartmentalization and closure processes that contribute to tree survival after fire injury. Preliminary observations of dissected fire scars from trees injured within the last decade showed centripetal development of wound-initiated discoloration (WID) through 2-3 decades of former sapwood in Larix occidentalis and Pseudotsuga menziesii. Although the WID reached and was apparently confluent with the visually similar heartwood, WID lacked the decay and insect resistance characteristics of heartwood. In contrast, development of WID in Pinus ponderosa,...

Fires that injure but do not kill trees cause scars used as proxies for the reconstruction of wildfire history. Understanding about these wildfires - and their relationship to vegetation dynamics and climate - has profoundly affected wildfire and land management policy globally. To better understand scarring in the context of wildfire behavior, landscape and biological processes, and tree species differences, we established a study on forests burned in 2003 near Missoula, Montana. We cut down small trees with visibly charred bark of species Larix occidentalis, Pseudotsuga menziesii, and...

Fire is a major disturbance agent in North American forests. Fires injure trees when heat transfer through the bark partially kills the cambium and the compartmentalization process results in a fire scar. Dendrochronologists use these scars in the xylem to reconstruct fire regimes. However, little information exists on the wood anatomy of fire scars. Consequently, this study quantifies changes in xylem (tracheid and ray traits) caused by fire-induced wounding in 2 individuals each of Larix occidentalis, Pseudotsuga menziesii and Pinus ponderosa. Transverse and tangential microsections were...

The Spring Mountains National Recreation Area (SMNRA) includes approximately 316,000 acres of National Forest System (NFS) lands managed by the Humboldt-Toiyabe National Forest in Clark and Nye Counties, Nevada (see fig. 1-1). The Spring Mountains have long been recognized as an island of endemism, harboring flora and fauna found nowhere else in the world. Conservation of the species endemic to and resident in the Spring Mountains is a goal described in the Organic Act for the SMNRA (Public Law 102-63, August 4, 1993).

Recent climatic trends and climate model projections indicate that climate change will modify rangeland ecosystem functions and the services and livelihoods that they provision. Recent history has demonstrated that climatic variability has a strong influence on both ecological and social components of rangeland systems and that these systems possess substantial capacity to adapt to climatic variability. Specific objectives of this synthesis are to: 1) evaluate options to mitigate greenhouse gas emissions and future climate change; 2) survey actions that individuals, enterprises, and social...

Regional and continental-scale forest and woodland mortality appears to be accelerating over recent decades (Allen et al., 2010; Peng et al., 2011). These contemporary increases in mortality are just the beginning, as temperature is rising rapidly and global models predict a large decline in the strength of the terrestrial carbon sink over the next century (Arora et al., 2013). Even if precipitation variability remains similar to historical patterns, chronic warming (and warming-associated extremes (Reichstein et al., 2013)) raise the likelihood of mortality through direct impacts on...

Model-data comparisons of plant physiological processes provide an understanding of mechanisms underlying vegetation responses to climate. We simulated the physiology of a pinon pine-juniper woodland (Pinus edulis-Juniperus monosperma) that experienced mortality during a 5 yr precipitation-reduction experiment, allowing a framework with which to examine our knowledge of drought-induced tree mortality. We used six models designed for scales ranging from individual plants to a global level, all containing state-of-the-art representations of the internal hydraulic and carbohydrate dynamics of...

Raster modeling is an integral component of spatial analysis. However, conventional raster modeling techniques can require a substantial amount of processing time and storage space, often limiting the types of analyses that can be performed. To address this issue, we have developed Function Modeling. Function Modeling is a new modeling framework that streamlines the raster modeling process by utilizing lazy reading methodologies. To assess the efficacy of Function Modeling, we compared the processing time and storage space required to execute six simulation using our newly developed...