Treesearch

Invertebrates, especially those dependent on woody debris for a portion of their life cycle, may be greatly impacted by the amount of downed wood retained following timber harvests. To document relationships between invertebrates and logging residues, we sampled invertebrates with pitfall traps placed near or far from woody debris in 10 recently (2013–2015) harvested sites in western North Carolina with varying levels of woody debris retention. We measured the groundcover and microclimate at each trap and estimated site‐level woody debris volume. We modeled predictors (e.g., site‐level...

Firebrands are an important agent of wildfire spread and structure fire ignitions at the wildland urban interface. Bark flake morphology has been highlighted as an important yet poorly characterized factor in firebrand generation, transport, deposition, and ignition of unburned material. Using pine species where bark flakes are the documented source of embers, we conducted experiments to investigate how bark structure changes in response to diurnal drying. Over a three-day period in a longleaf pine (Pinus palustris Mill.) stand in Florida, we recorded changes in temperature, moisture...

We present a new R package to provide dendroecologists with tools to infer, quantify, analyze, and visualize growth suppression events in tree rings. dfoliatR is based on the OUTBREAK program and builds on existing resources in the R computing environment and the well-used dplR package. It is designed to aid research in the ecology of insect defoliation events and to reconstruct defoliator outbreak chronologies, but can be applied to other studies where host-non-host comparisons are useful. dfoliatR performs an indexing procedure to remove climatic signals in the host-tree series that are...

Attributes of deadwood in forests, including quantity, landscape position, and state of decay, influence numerous ecosystem processes such as wildfire behavior, tree regeneration, and nutrient cycling. Attributes of deadwood that vary over subdiurnal time steps, including moisture, have not been routinely measured despite the profound effects they have on ecosystem processes. To improve our understanding of forest deadwood subdiurnal moisture dynamics, we installed an intensive time-domain reflectometry (TDR) sensor network in a log and surrounding soil within a northern hardwood forest in...

Reductions in snow accumulation and melt in headwater basins are increasing the water stress on forest ecosystems across the western US. Forest thinning has the potential to reduce water stress by decreasing sublimation losses from canopy interception; however, it can also increase snowpack exposure to sun and wind. We used the high-resolution (1 m) energy and mass balance Snow Physics and Lidar Mapping (SnowPALM) model to investigate the effect of two virtual forest thinning scenarios on the snowpack of two adjacent watersheds (54 km2total) in the Lake Tahoe Basin, California, where...

Increased genotypic diversity has been associated with increased biomass production in shortrotationtree species. Increasing the genotypic diversity of loblolly pine (Pinus taeda L.) in an attempt toincrease productivity has not been extensively studied nor tested operationally or over long durations (i.e.,>7 yr). We used genetically mixed and pure rows of loblolly pine growing throughout its planted range—Virginia, North Carolina, and Brazil—to test the effects of genetic mixing on volume production. Therewere no significant effects of mixing rows compared to pure rows on uniformity or...

The U.S. Fish and Wildlife Service (USFWS) developed an invasive species risk assessment procedure, presented in Marcot et al. (2019), consisting of an existing rapid assessment process for plants and animals (Ecological Risk Screening Summary; ERSS) and a new probability-based Bayesian network model (Freshwater Fish Injurious Species Risk Assessment Model; FISRAM), that may be used to help prioritize invasive freshwater fish species for Federal injurious wildlife listing evaluation by USFWS under the Lacey Act. Hill et al. (2020) provided a rebuttal letter of Marcot et al. (2019) but did...

In this study, water level models are constructed to characterize mangrove flooding across urban gradients in Puerto Rico. The most urban sites exhibited 95% longer hydroperiods, 23% lower flood frequencies, and 110% lower depths than the least urban sites. Rainfall importance was explained more by geomorphology and tidal connectivity than by urbanization, but there was evidence for changes in tidal amplitudes along the urban gradient. Relationships between surface water chemical metrics and land cover contradicted previous studies by suggesting lower nutrients and biochemical oxygen...

This study characterizes the structure and composition of mangrove forests across urban gradients in Puerto Rico. It then uses a suite of hydrologic, water chemistry, and land cover variables to test for the relative importance of urban intensity alongside flooding and water chemistry in explaining observed variability in forest structure and composition. Three separate statistical tests suggest a significant but limited influence of urbanness on forest composition and structure. In the most urban sites, the diameters of the largest trees were 27% larger, but all structural measurements...