Treesearch

The introduction of Adelges tsugae (Hemlock Woolly Adelgid [HWA]) to the eastern United States has had a devastating impact on Tsuga canadensis (Eastern Hemlock). Although much research has been done to assess HWA impacts on ecosystem processes and vegetation structure, few researchers have examined community-level changes in highly infested forest stands. Here we assess the impact of Eastern Hemlock mortality on vegetation and invertebrate diversity and community structure by comparing low-impact (healthy) stands and stands heavily impacted by HWA. We sampled the vegetative and invertebrat...

Biomass like wood chips, switchgrass and other plant residues are first converted to syngas through gasification process using air, oxygen or steam. A downdraft gasifier is performed for syngas production in Mississippi State. The syngas from the gasifier contains up to 49% (vol) N2. High-level nitrogen-containing (nitrogen can be up to 60%) synthesis gas is converted to liquid hydrocarbon mixture through a one-stage catalytic process with a FeePd/ZSM-5 catalyst. The FeePd/ZSM-5 catalyst shows relatively high activity and selectivity in producing liquid hydrocarbons when running with...

Long-term research on freshwater ecosystems provides insights that can be difficult to obtain from other approaches. Widespread monitoring of ecologically relevant water-quality parameters spanning decades can facilitate important tests of ecological principles. Unique long-term data sets and analytical tools are increasingly available, allowing for powerful and synthetic analyses across sites. Long-term measurements or experiments in aquatic systems can catch rare events, changes in highly variable systems, time-lagged responses, cumulative effects of stressors, and biotic responses that...

Fire-adapted forests of the Lake States region are poorly studied relative to those of the western and southeastern United States and our knowledge base of regional short- and long-term fire effects on soils is limited. We compiled and assessed the body of literature addressing fire effects on soils in Lake States forests to facilitate the re-measurement of previous studies for the development of new long-term datasets, and to identify existing gaps in the regional knowledge of fire effects on forest soils. Most studies reviewed addressed fire effects on chemical properties in pine-dominate...

Management strategies to restore forest landscapes are often designed to concurrently reduce fire risk. However, the compatibility of these two objectives is not always clear, and uncoordinated management among landowners may have unintended consequences. We used a forest landscape simulation model to compare the effects of contemporary management and hypothetical restoration alternatives on fire risk in northern temperate and southern boreal forests of the Border Lakes Region in Minnesota, USA, and Ontario, Canada. Six main model scenarios simulated different combinations of timber...

Riparian management zones (RMZs) protect streams from excess nutrients, yet few studies have looked at soil nutrients in forested RMZs or the impacts of partial harvesting on nutrient availability. We investigated the impacts of upland clearcutting in conjunction with uncut and partially harvested RMZs (40% basal area reduction) on soil nutrients in forests in Minnesota, USA. Nitrate, ammonium, and phosphorus were measured using exchange resins. Upland clearcutting increased dormant and growing season nitrate, ammonium, and total inorganic nitrogen in the upland 2 to 5 times compared with...

Urea is well known to have a synergistic action with phosphorus-based flame retardants (FRs) in enhancing the FR performance of cellulosic materials, but the effect of urea on the thermal decomposition kinetics has not been thoroughly studied. In this study, the activation energy (Ea) for the thermal decomposition of greige cotton nonwoven fabrics treated with various amounts of urea at fixed contents of diammonium phosphate (DAP), was measured using the Kissinger, Friedman, and Flynn-Wall-Ozawa methods. The three methods produced consistent results revealing a dual function of urea...

The article presents comparative data for aboveground biomass, wood volume, nutirent stocks (N, P, K) and leaf litter in different types of forests in Puerto Rico. The aim of the study is to assess how novel forests of Castilla elastica, Panama Rubber Tree, and Spathodea campanulata, African Tulip Tree, compare with tree plantations and native historical forests (both secondary and mature). It found that novel forests of these two species can accumulate large quantities of biomass and nutrients above ground, that they do so at a rapid rate and that they exhibit high rates of leaf fall....

This essay describes our effort to develop a practical approach to the integration of the social and ecological sciences in the context of a Latin-American city such as San Juan, Puerto Rico. We describe our adaptive social-ecological approach in the historical context of the developing paradigms of the Anthropocene, new integrative social and ecological sciences, and the social and ecological conditions in San Juan. The problems faced by tropical cities are more complex than implied by isolated studies of their sociology and ecology, a situation that demands a higher level of integration...