Treesearch

The western pine beetle (WPB), Dendroctonus brevicomis LeConte, is a major mortality agent of pines in North America. A total of 706 adults of WPB from 81 geographical sites were analyzed with traditional and geometric morphometric methods to evaluate the variation of discrete and quantitative morphological characters with particular attention to the antenna, spermatheca, and seminal rod. Principal coordinates and canonical variate analyses supported three geographical groups in WPB: (1)West, from British Columbia to southern California along the Pacific coast, Idaho, and Montana; (2)...

A simple and novel method, self-assembly of nanocellulose and nanochitin, was developed to produce high-efficiency and versatile biohybrid hydrogel (BHH) and aerogel (BHA) for water purification. The self-assembly process was driven by the electrostatic force between one-dimensional (1D) negatively charged TEMPO-oxidized cellulose nanofiber (TOCNF) and positively charged partly deacetylated chitin nanofiber (PDChNF). The self-assembly process was performed at room temperature and without adding any crosslinking agents throughout the process. This results in the threedimensional (3D) BHH...

There is an increasing attention to cellulose nanofibrils (CNFs) for food packaging applications due to their abundance, biodegradability, and low gas permeability. In this work, oxygen and water barrier performance is studied for bio-nanocomposite films formed by incorporation of two types of bentonite (PGN and PGV) at different loads (15, 30 and 45 wt%) into continuous CNF matrix. The resulting hybrid films were analyzed for their morphology, surface energy, mechanical strengths as well as water/oxygen barrier qualities. Both types of bentonite lowered the CNF degradation temperature and...

This short paper provides the framework and introduction to this special issue of International Journal of Wildland Fire. Its eight papers were selected from those presented at two consecutive conferences held in 2018 in Europe and the USA that focussed on the impacts of wildfire on factors that regulate streamflow, water quality, sediment transport, and aquatic habitats. Despite decades of watershed research, our understanding of the effects of wildfires on the processes that regulate clean water supply remains limited. Here, we summarise the key challenges and research needs in this...

An open source computational fluid dynamics (CFD) solver has been incorporated into the WindNinja modeling framework. WindNinja is widely used by wildland fire managers, as well as researchers and practitioners in other fields, such as wind energy, wind erosion, and search and rescue. Here, we describe the CFD solver and evaluate its performance against the WindNinja conservation of mass (COM) solver, and previously published large-eddy simulations (LES), for three field campaigns with varying terrain complexity: Askervein Hill, Bolund Hill, and Big Southern Butte. We also compare the...

Sonderegger pine (Pinus x sondereggeri H.H. Chapm.) is a hybrid pine species of loblolly pine (Pinus taeda L.) and longleaf pine (Pinus palustris Mill.) that is culled when noticed during seedling processing and packing in the nursery. Early indication of the hybrid has been theorized as the absence of a seed wing stub or hypocotyl lift off of the growing medium surface, although neither of these theories has been proven. Two trials were conducted to determine the role of container cell color, growing medium depth in the cells, and the presence of a seed wing stub on longleaf pine hypocotyl...

Sugarberry (Celtis laevigata) is a common native tree up to 80 ft tall that is found throughout much of the South, ranging from southeastern Virginia to South Florida and west to central Texas. High rates of sugarberry mortality were first reported in Columbia, South Carolina in 2009. The issue has since expanded westward beyond the Savannah River and eastward to the coasts of South Carolina and Georgia (Fig. 1). Although mortality is most conspicuous in urban and residential areas, large numbers of sugarberry are dying in forested areas as well. This is by far the most severe and widesprea...

Large dams and their respective reservoirs provide renewable energy and water security, but also can profoundly alter riverine ecosystems. Here, we present evidence of changing aquatic food web structure in the seasons following short-duration, extreme manipulation of water levels in a reservoir (i.e., draining of the reservoir to the original riverbed during fall to assist outmigration of juvenile Chinook Salmon). We find unintended and lagged consequences of transitioning from a lake to a river, even temporarily, that resulted in trophic shifts away from piscivory and towards feeding at...

Natural areas are tracts of land with little or no evidence of past human influence and designated for research, education, and conservation. Many sites were selected to represent high-quality examples of both common and rare plant association groups. However, the extent to which natural areas characterize regional environmental conditions or gradients important for measuring and understanding the effects of climate change has not been examined. We compared the current collection of natural areas in Oregon and Washington to the broader natural ecosystems found in the region using four...

Conservation practitioners are increasingly looking to species translocations as a tool to recover imperiled taxa. Quantitative predictions of where animals are likely to move when released into new areas would allow managers to better address the social, institutional, and ecological dimensions of conservation translocations. Using >5 million California condor (Gymnogyps californianus) occurrence locations from 75 individuals, we developed and tested circuit-based models to predict condor movement away from release sites. We found that circuit-based models of electrical current were well...