Treesearch

Introduction: The Aspen-FACE experiment was an 11-year study of the effect of elevated CO2 and ozone (alone and in combination) on the growth of model aspen communities (pure aspen, aspen-birch, and aspen-maple) in the field in northern Wisconsin, USA. Uncertainty remains about how these short-term plotlevel responses might play out over broader temporal and spatial scales where climate change, competition, succession, and disturbances interact with tree-level responses. In this study, we used a new physiologybased approach (PnET-Succession v3.1) within the forest landscape model LANDIS-II...

American chestnut (Castanea dentata) was once an important component forests in the central Appalachians (USA), but it was functionally extirpated nearly a century ago. Attempts are underway to reintroduce blight‐resistant chestnut to its former range, but it is uncertain how current forest composition, climate, and atmospheric changes and disturbance regimes will interact to determine future forest dynamics and ecosystem services. The combination of novel environmental conditions (e.g. climate change), a reintroduced tree species and new disturbance regimes (e.g. exotic insect pests, fire...

This Species Review summarizes the fire effects information and relevant ecology of kingcup cactus in North America that was available in the scientific literature as of 2018. Kingcup cactus is a small cactus native to the American Southwest. It typically grows in rocky crevices in shrublands and conifer woodlands, and fingers into desert grasslands at low elevations. Its stems occur singly or in mounds up to 4 feet in diameter. Only limited information was available on regeneration and successional patterns of kingcup cactus. Hummingbirds and bees pollinate the flowers, and ants may...

Confirming presence and distribution of a species is necessary for effective conservation. However, obtaining robust occupancy estimates and confidently identifying factors important to occupancy may be difficult for rare and elusive species. Further, in surveys to assess presence, false-positive detections bias results; however, false-positive occupancy models can resolve this bias and, thus, better support conservation. We assessed the performance of false-positive versus standard occupancy models and important factors predicting presence for a low-density bat population in the southern...

Stable and durable wood products can be produced by chemical modification at the molecular level. One modification that is effective in achieving these properties is by reacting both hardwoods and softwoods with acetic anhydride. The reaction takes place in the most accessible hydroxyl groups in the cell wall polymers. Lignin reacts the fastest followed by the hemicelluloses. Both are highly substituted. As the level of bonded acetyl increases, dimensional stability increases and attack by fungi decreases. The threshold of fungal resistance is approximately 18% acetyl. The moisture in the...

Kraft lignin was catalytically graphitized to graphene-based nanostructures at 1000 C under argon atmosphere with four iron catalysts, iron(III) nitrate (Fe-N); iron(II) chloride (Fe-Cl2); iron(III) chloride (Fe-Cl3); and iron(II) sulfate (Fe-S). The catalytic decomposition process of iron-promoted lignin materials was examined using thermalgravimetric analysis and temperature-programmed decomposition methods. The crystal structure, morphology and surface area of produced materials were characterized by means of X-ray diffraction, Raman, scanning electronmicroscopy, high resolution...

Habitat loss, wind energy development, and the disease white-nose syndrome are majorthreats contributing to declines in bat populations in North America. In the southeastern US in particular, the recent arrival of white-nose syndrome and changes in landscape composition and configuration have driven shifts in bat species populations and distributions. Effective management strategies which address these large-scale, community-level threats require landscape-scale analyses. Our objective was to model the relationship between ecoregional and landscape factors and occupancy by all bat species...

Citizen science programs are not static; they change over time in response to new program priorities and emerging technologies, as well as to improve work flow for program staff and volunteers. In this article, the authors present a case study of an evolving urban forestry citizen science program at the Pennsylvania Horticultural Society, a nonprofit organization in Philadelphia, Pennsylvania, U.S. The Tree Checkers program involves tree stewards recording data each summer about recently planted tree survival, growth, crown vigor, and maintenance, while also engaging their neighbors to...

Lignin nanoparticles (LNPs) from renewable lignocelluloses can be a valuable building block for a variety of applications and could contribute to the economic development in rural agricultural communities. Current technologies for producing LNPs are not cost effective and use toxic solvents. In this study, LNPs were produced by fractionating poplar wood at ≤80°C with a recyclable hydrotrope p-toluenesulfonic acid (p-TsOH) in an aqueous system. The dissolved lignin was separated as LNPs simply by diluting the spent liquor (SL) to the minimal hydrotrope concentration (HCmin) of 11.5%. The...

This paper examined the effect of cellulose nanocrystal (CNC) content on water vapor permeability (WVP) and oxygen permeability (OP) of extrusion-blown poly(lactic acid) (PLA) films recorded at various temperatures and relative humidities. While both WVP and OP followed the Arrhenius equation, the WVP decreased with increasing temperature whereas an opposite trend was observed for OP, resulting in negative activation energy (Ep) for WVP but positive Ep for OP, regardless of CNC content. However, the Ep for both WVP and OP increased by adding CNC into PLA matrix. WVP was not affected by the...