Treesearch

Research Highlights: The biology of mountain pine beetle (MPB), Dendroctonus ponderosae Hopkins, in Colorado’s lodgepole pine forests exhibits similarities and differences to other parts of its range. Brood emergence was not influenced by stand density nor related to tree diameter. The probability of individual tree attack is influenced by stocking and tree size. Findings have implications for understanding MPB as a disturbance agent and for developing management strategies. Background and Objectives: MPB causes extensive tree mortality of lodgepole pine, Pinus contorta Douglas ex Loudon,...

A better understanding of the response of plant growth to elevational gradients may shed light on how plants respond to environmental variation and on the physiological mechanisms underlying these responses. This study analyzed whole plant growth and physiological and morphological properties of needles in young Pinus koraiensis Sieb. et Zucc. trees at thirteen points along an elevational gradient ranging from 750 to 1350mabove sea level (a.s.l.) at the end of a growing season on Changbai Mountain in northeastern China. Sampling and analyses indicated the following; (1) many needle...

In mixed-species forests, species composition of the overstorey affects regeneration processes through its influence on seed rain intensity and micro-site characteristics. Based on extensive inventory data (1583 sample plots), this study investigated relationships between the percentages of silver fir (Abies alba Mill.), European beech (Fagus sylvatica L.), and Norway spruce (Picea abies (L.) H. Karst.) in the overstorey and in naturally established regeneration (seedlings of a height below 0.5 m). A useful framework for this analysis was the assumption that for a given stand density level...

Our planet is changing rapidly, with large scale forest loss and degradation occurring. Forest restoration has taken place in the last century, generally with a limited focus on a handful of benefits. Efforts to scale up forest restoration, while meeting multiple benefits, have been expanded recently, notably through global targets and massive government commitments towards forest landscape restoration (FLR). Yet while much political will has been generated for FLR, action on the ground remains limited. We propose six types of integration that can help truly scale up FLR efforts, namely:...

How fire interacts with an ecosystem is driven by forest structure, fuel bed heterogeneity, topography, and weather. The juxtaposition of two distinct vegetation types with divergent properties can further influence the effects of fire on an ecosystem. In the southeastern United States, pine flatwoods and hardwood–cypress swamps are distinct ecosystems that can be geographically intermixed as a function of elevation, affecting how fires move across the landscape. We sought to understand the consequence of extreme fire weather on landscape wildfire severity and biomass accumulation taking...

A mail survey was conducted in 2017 to assess the status of Minnesota's logging sector during 2016. Minnesota's logging businesses continue to be characterized by a disparity between business size and percentage of total annual production volume. A small percentage of the businesses were classified as harvesting greater than 15,000 cords annually. However, those businesses produced a high percentage of the total harvest volume. Conversely, a large percentage of the businesses were classified as harvesting fewer than 5,000 cords annually, but produced a low percent of total reported volume...

The Great Plains is the grasslands of the central United States, but precise delineation of this region has evaded agreement due to the transition between Great Plains grasslands and forests of the eastern United States. After comparing Great Plains delineations in readily available geographic information system layers, I established a northeastern boundary using evidence from historical tree surveys during the 1800s. Additionally, I described tree presence within the Great Plains over time and potential drivers of change. The definition documented here diverges from others by including...

An accurate simulation of the sensible heat flux (H) over vegetation from thermal remote sensing requires an a priori estimate of roughness length and the excess resistance parameter kB-1. Despite being the subject of considerable interest in hydrometeorology, there still does not exist a uniform method for estimating roughness length from remote sensing techniques. This study demonstrates a turbulent diffusion method to simulate canopy‐air sensible heat. The performance of the roughness length scheme as described in Chen et al. (2013, https://doi.org/10.1175/JAMC‐D‐12‐056.1) was examined...

A lack of optimal gene combinations, as well as low levels of genetic diversity, is often associated with the formation of species range margins. Conservation efforts rely on predictive modelling using abiotic variables and assessments of genetic diversity to determine target species and populations for controlled breeding, germplasm conservation and assisted migration. Biotic factors such as interspecific competition and hybridization, however, are largely ignored, despite their prevalence across diverse taxa and their role as key evolutionary forces. Hybridization between species with...

Floodplains are comprised of aquatic and terrestrial habitats that are reshaped frequently by hydrologic processes that operate at multiple spatial and temporal scales. It is well established that hydrologic and geomorphic dynamics are the primary drivers of habitat change in river floodplains over extended time periods. However, the effect of fluctuating discharge on floodplain habitat structure during seasonal flooding is less well understood. We collected ultra-high resolution digital multispectral imagery of a gravel-bed river floodplain in western Montana on 6 dates during a typical...