Treesearch

Background and Objectives: In northern Vietnam, nearly 37,100 hectares of mangroves were lost from 1964–1997 due to unsustainable harvest and deforestation for the creation of shrimp aquaculture ponds. To offset these losses, efforts in the late 1990s have resulted in thousands of hectares of mangroves being restored, but few studies to date have examined how effective these efforts are at creating restored mangrove forests that function similarly to the intact mangroves they are intended to replace. Materials and Methods: We quantified and compared soil carbon (C) stocks among restored...

In Sierra Nevada mixed-conifer forests, heterogeneity in overstory tree spatial patterns is an important ecological characteristic associated with resilience to frequent fires. Regional managers often emphasize this heterogeneity as a key component of forest treatments. There is a lack of information about how the dimensions of fire-resilient tree spatial patterns might vary with topography, which is an important influence on forest structure. We mapped, analyzed, and compared overstory tree spatial patterns across three topographic slope positions (ridges, mid-slopes, and valleys) in...

Efforts to conserve biodiversity increasingly focus on identifying climate‐change refugia – areas relatively buffered from contemporary climate change over time that enable species persistence. Identification of refugia typically includes modeling the distribution of a species’ current habitat and then extrapolating that distribution given projected changes in temperature and precipitation, or by mapping topographic features that buffer species from regional climate extremes. However, the function of those hypothesized refugia must be validated (or challenged) with independent data not...

Forest pathogens are important drivers of tree mortality across the globe, but it is exceptionally challenging to gather and build unbiased quantitative models of their impacts. Here we harness the rare data set matching the spatial scale of pathogen invasion, host, and disease heterogeneity to estimate infection and mortality for the four most susceptible host species of Phytophthora ramorum, an invasive pathogen that drives the most important biological cause of tree mortality in a broad geographic region of coastal California and southwest Oregon. As of 2012, the most current field...

Mountain pine beetle, Dendroctonus ponderosaeHopkins (Coleoptera: Curculionidae), is the most important forest insect in western North America. We determined causes and rates of tree mortality and changes in forest structure and composition associated with D. ponderosaeoutbreaks in the Intermountain West, U.S. during 2004–2019 based on a network of 125 0.081-ha circular plots installed in Colorado, Idaho, Montana, Utah and Wyoming. Incipient populations of D. ponderosaebegan in 2004; peaked in 2007; and returned to endemic levels in 2011 in Idaho, Montana, Utah and Wyoming. In Colorado,...

Understanding the factors influencing the current distribution of genetic diversity across a species range is one of the main questions of evolutionary biology, especially given the increasing threat to biodiversity posed by climate change. Historical demographic processes such as population expansion or bottlenecks and decline are known to exert a predominant influence on past and current levels of genetic diversity, and revealing this demo-genetic history can have immediate conservation implications. We used a whole-exome capture sequencing approach to analyze polymorphism across the...

Variations in long-term precipitation trends due to climate forcings have been observed in manyparts of the world, exacerbating hydrological uncertainties to predicting droughts, floods, waterresource availability, and ecosystem services. The Lower Mississippi River Alluvial Valley (LMRAV) isan important economic region of the midsouth USA, which is prone to natural disasters from extremeclimate events and is known historically for cyclic flooding events and, within the last 20 years, forgroundwater level declines. However, our knowledge of long-term precipitation trends in this regionis...

In 2014–2019, we conducted six experiments in north-central Georgia in an attempt to verify the aggregation pheromone response of the ambrosia beetle Gnathotrichus materiarius (Fitch) (Coleoptera: Curculionidae: Scolytinae: Scolytini: Corthylina) to sulcatol known to be produced by male G. materiarius; we failed to catch any G. materiarius. However, we did find that another corthyline ambrosia beetle species Monarthrum mali (Fitch) was attracted to (R)-(–)-sulcatol, whereas the longhorn beetle Leptostylus asperatus (Haldeman) (Coleoptera: Cerambycidae: Lamiinae) was attracted to (S)-(+)-sul...

An unprecedented conservation effort is underway across 11 western states to address risks to sagebrush ecosystems and the species that depend on them. The sagebrush biome - the largest biome in the Lower 48 states - provides a large diversity of habitats and supports more than 350 species of conservation concern. Since Euro-American settlement in the mid-1800s, this “sagebrush sea” has been reduced in area by nearly half and many of the remaining sagebrush ecosystems have been significantly altered.

The present study investigated the effects of exposure of bamboo–plastic composites to three aggressive fungi species on mass loss values. Polyvinyl chloride was used as the synthetic matrix of the composite. Three mixing combinations were used for bamboo– polymer composites, namely 40/60, 50/50, and 60/40. The injection-molded process was employed to produce the composites. Specimens were prepared according to modified European standard specifications (EN-113) to be exposed to white-, brown-, and softrot fungi each month for 4 months. The results indicated that the soft-rot fungus...