Treesearch

We linked state-and-transition simulation models (STSMs) with an economics-based timber supply model to examine landscape dynamics in North Carolina through 2050 for three scenarios of forest biomass production. Forest biomass could be an important source of renewable energy in the future, but there is currently much uncertainty about how biomass production would impact landscapes. In the southeastern US, if forests become important sources of biomass for bioenergy, we expect increased land-use change and forest management. STSMs are ideal for simulating these landscape changes, but the...

The systemic insecticide imidacloprid is commonly used to protect trees against attack by the Adelges tsugae (Hemlock Woolly Adelgid [HWA]), an invasive pest that threatens Tsuga canadensis (Eastern Hemlock) and T. caroliniana (Carolina Hemlock) in eastern North America. Although there have been some studies documenting the short-term (1–3 years) impact of imidacloprid on non-target arthropods in hemlock systems, almost nothing is known about the impact over longer time scales. Here, using a set of trees which were experimentally treated 3 and 9 years prior to this study, we found that...

Stand age and disturbance data have become more available in recent years and can facilitate modeling studies that integrate and quantify effects of disturbance and nondisturbance factors on carbon dynamics. Since high-quality disturbance and forest age data to support forest dynamic modeling are lacking before 1950, we assumed dynamic equilibrium (carbon neutrality) for the starting conditions of forests with unknown historical disturbance and forest age information. The impacts of this assumption on forest carbon cycle estimation for recent decades have not been systematically examined....

Key message. Three options are proposed to improve the accuracy of national forest biomass estimates and decrease the uncertainty related to tree model selection depending on available data and national contexts. Introduction. Different tree volume and biomass equations result in different estimates. At national scale, differences of estimates can be important while they constitute the basis to guide policies and measures, particularly in the context of climate change mitigation. Method. Few countries have developed national tree volume and biomass equation databases and have explored its...

Wildfire may cause major losses of forest soil organic matter and consequently limit soil nutrient availability and forest regeneration, although the characteristics of post-fire organic matter are also likely to influence these processes. The 2011 Pagami Creek wildfire in northern Minnesota was a historical fire event and resulted in a range of fire severity levels determined via remote sensing and field measurements. To evaluate the effects of fire severity on forest soil organic matter, we sampled soils immediately following fire in areas and quantified total soil carbon (C) and...

Tricinwas recently discovered in lignin preparations from wheat (Triticum aestivum) straw and subsequently in all monocot samples examined. To provide proof that tricin is involved in lignification and establish the mechanism by which it incorporates into the lignin polymer, the 4′-O-β-coupling products of tricin with the monolignols (p-coumaryl, coniferyl, and sinapyl alcohols) were synthesized along with the trimer that would result from its 4′-O-β-coupling with sinapyl alcohol and then coniferyl alcohol. Tricin was also found to cross couple with monolignols to form tricin-(4′-O-β)-linke...

Natural enemies and environmental factors likely both influence the population cycles of many forestdefoliating insect species. Previous work suggests precipitation influences the spatiotemporal patterns of gypsy moth outbreaks in North America, and it has been hypothesized that precipitation could act indirectly through effects on pathogens. We investigated the potential role of climatic and environmental factors in driving pathogen epizootics and parasitism at 57 sites over an area of ≈72,300 km2 in four US mid-Atlantic states during the final year (2009) of a gypsy moth outbreak. Prior...

Large birds regularly use updrafts to subsidize flight. Although most research on soaring bird flight has focused on use of thermal updrafts, there is evidence suggesting that many species are likely to use multiple modes of subsidy. We tested the degree to which a large soaring species uses multiple modes of subsidy to provide insights into the decision-making that underlies flight behaviour. We statistically classified more than 22 000 global positioning satellite–global system for mobile communications telemetry points collected at 30-s intervals to identify the type of subsidized...

The storage-discharge relationships of 26 watersheds in the inland Pacific Northwest of the United States were analyzed. Four fitting methods were used to obtain the baseflow coefficients: lower envelope, organic correlation, and ordinary and inverse least squares. Several climatic and terrain attributes were evaluated as predictors of baseflow coefficients. Watersheds dominated by basalt and flatter landscapes exhibited the smallest recession time scales (K) (12.5-20.0 days). Greater K values (33.3-66.7 days) were obtained over catchments dominated by metamorphic and sedimentary rocks....

The effective number of breeders that give rise to a cohort (Nb) is a promising metric for genetic monitoring of species with overlapping generations; however, more work is needed to understand factors that contribute to variation in this measure in natural populations. We tested hypotheses related to interannual variation in Nb in two longterm studies of brook trout populations. We found no supporting evidence for our initial hypothesis that ^Nb reflects ^Nc (defined as the number of adults in a population at the time of reproduction). ^Nb was stable relative to ^NC and did not follow...