Treesearch

tUltraviolet-filters (UV-filters) and estrogens have attracted increased attention as contaminants of emerging concern (CECs) due to their widespread occurrence in the environment. Most of these CECs are hydrophobic and have the potential to accumulate in aquatic organisms. To date, co-analysis of UV-filters and estrogens has not been reported due, in part, to the complex environmental matrices. Here, a multi-residue method has been developed for simultaneous determination of five UV-filters and three estrogens in tissue from aquatic and marine organisms. The procedure involved a modified...

Limber pine, designated by Rocky Mountain National Park (RMNP) as a Species of Management Concern, is a keystone species that maintains ecosystem structure, function, and biodiversity. Limber pine is declining in the park due to the interacting effects of recent severe droughts and the climate-exasperated mountain pine beetle (Dendroctonus ponderosae) outbreak, and is threatened by the invasion of the non-native pathogen (Cronartium ribicola) that causes the lethal disease white pine blister rust (WPBR). White pine blister rust was confirmed in the park in 2010 (Schoettle et al. 2011;...

Many North American landbird populations have declined in recent decades, including those that occupy Western forest habitats. Long-term monitoring of abundance and vital rates allows us to detect species and habitats of concern, and to identify potential management actions. Here, we analyze capture data from a regional network of 10 banding sites in the Klamath-Siskiyou Bioregion, USA, to examine demographic trends for 12 Western forest bird species from 2002 to 2013. Adult abundance declined significantly in some breeding populations of Audubon's Yellow-rumped Warbler (Setophaga coronata...

Given the substantial role that forests play in removing CO2 from the atmosphere, there has been a growing need to evaluate the carbon (C) implications of various forest management and land-use decisions. Although assessment of land-use change is central to national-level greenhouse gas monitoring guidelines, it is rarely incorporated into forest stand-level evaluations of C dynamics and trajectories. To better inform the assessment of forest stand C dynamics in the context of potential land-use change, we used a region-wide repeated forest inventory (n = 71 444 plots) across the eastern...

Understanding the patterns of tree recruitment is essential to quantifying the future health and productivity of forest ecosystems. Using national forest inventory information, we incorporated browse impact measurements into models of sapling (2.5–12.7 cm diameter at breast height (DBH)) and overstory tree (≥12.7 cm DBH) ingrowth across the northern United States. Ingrowth was modeled with standard and zero-inflated techniques using discrete Poisson and negative binomial distributions. Zero-inflated models using stand attributes and browse impacts provided the best fit statistics for...

Quantifying the density of live trees in forest stands and partitioning it between species or other stand components is critical for predicting forest dynamics and responses to management, as well as understanding the impacts of stand composition and structure on productivity. As plant traits such as shade tolerance have been proven to refine understanding of plant community dynamics, we extended a previous model relating maximum stand density to wood specific gravity to incorporate shade tolerance as an additional functional trait. Additionally, we included climatic variables that might...

Frequently burned low-latitude coniferous forests maintain a high-diversity understory. Longleaf pine (Pinus palustris Mill.) forests and woodlands have exceptionally high diversity at fine scales and very frequent fire return intervals (1–3 yr). Furthermore, the positive association between high-frequency, low-intensity surface fires and high species richness in longleaf pine ecosystems is well documented but poorly understood. Recent studies have demonstrated additional linkages between specific fuel assemblages and fire intensity at small spatial scales. In this study, we build upon...

Airborne lidar has become a well-suited technology for predicting and mapping many tropical forest attributes, including aboveground biomass (AGB). However, trade-offs exist between lidar pulse density and acquisition cost. The aim of this study was to evaluate the influence of lidar pulse density on AGB change predictions using airborne lidar and field plot data in a tropical rain forest located near Paragominas, Pará, Brazil. In the field, AGB was computed at 84 square field plots of 50x50m in 2014. The lidar data were acquired 2012 and 2014, and for each dataset the pulse density was...

In 2007, Russia imposed an ad valorem tax on its log exports that lasted until 2012. In this paper, weuse a Muth-type equilibrium displacement model to investigate the market and welfare impacts of this tax, utilizing a vertical linkage between log and lumber markets and considering factor substitution. Our theoretical analysis indicates that, without considering the vertical linkage, the negative effects of log export tax on equilibrium price for log producers is underestimated when logs and processing services are gross substitutes, and the direction of bias is uncertain when they are...

Almost immediately after he started in the fall of 1945, Henry H. “Hank” Chamberlin faced many challenges in getting the two-year applied forestry program at Arkansas A&M College (AA&M) up and running. As the newly hired director of the one-man department, Chamberlin needed to build this program with virtually no financial resources, a flawed curriculum, very limited office and instructional space, and no other dedicated faculty. Perhaps it was a good thing that only three students had enrolled in the forestry program during its first term. These challenges, daunting as they were, did not...