Treesearch

The vertical source-sink distribution of air pollutants within and above forested canopies is necessary for describing the biological, physical, and chemical processes influencing the soil-vegetation-atmosphere exchange. This study implemented inverse modeling methods to estimate the source-sink and flux profiles of reactive nitrogen (N) and sulfur (S) compounds from measurements of the mean concentration profiles of ammonia (NH3), nitric acid (HNO3), sulfur dioxide (SO2), and particulate ammonium (NH4+), nitrate (NO3−), and sulfate (SO42−) at a forest site in the southern Appalachian...

Invasive plant species (IPS)1 have been monitored on select Phase 2 (P2) FIA plots since 2005 in the Midwest and since 2007 in the northeastern part of the NRS region. In 2005 and 2006, IPS data were collected year-round on 100 percent of the plots. Starting in 2007, the sampling intensity changed to collecting IPS data on 20 percent of plots with the monitoring window running from May through September. Since 2012, IPS data are collected on the Phase 2 Plus (P2+) sample. These plots are a 12.5 percent subsample of the Phase 2 plots, measured from May through September, and only occur on...

The 2012–2016 hotter drought in the Sierra Nevada, California, USA led to the mortality of millions of trees. This disruption to the disturbance regime is an example of how climate extremes can exacerbate current and future wildfire risks. In this study, we used data from an extensive network of forest plots across 13 different sites in the Sierra Nevada to characterize ground (i.e., duff) and surface fuels and their potential drivers shortly after the drought (2016–2018), but before snag (standing dead tree) fall associated with this massive tree mortality event occurred. Overall, we...

Context Forest loss and fragmentation pose extreme threats to biodiversity. Their efficient characterization from remotely sensed data therefore has strong practical implications. Data are often separately analyzed for spatial fragmentation and disorder, but no existing metric simultaneously quantifies both the shape and arrangement of fragments. Objectives We present a fractal fragmentation and disorder index (FFDI), which advances a previously developed fractal index by merging it with the Rényi information dimension. The FFDI is designed to work across spatial scales, and to effciently...

Caterpillars (larval Lepidoptera) are an essential link in trophic networks of forest ecosystems, as they serve as herbivores of vegetation and a food source for many organisms. Phenological mismatches between caterpillars, host plants, or predators may have negative effects across multiple trophic levels. Seasonal timing of caterpillar emergence and peak occurrence may be impacted by climate change, however, studying caterpillar phenology at broad spatial scales is challenging due to lack of data availability. Here, we examine two sources of caterpillar observations, opportunistic records...

Lodgepole pine (Pinus contorta var. latifolia) has a reputation for indestructibility, but recent events in the Southern Rockies may have pushed even this stalwart species to the edge. Research by Rocky Mountain Research Station (RMRS) scientist Chuck Rhoades and colleagues shows that lodgepole forests burned by wildfires following mountain pine beetle outbreaks may not generate enough seedlings to return to predisturbance tree densities.

We applied a systematic global literature survey from the last 2.5 years on spatiotemporal population dynamics — broadly defined — of Lepidopteran forest pests. Articles were summarized according to domain-specific (planetary ecology — remote sensing, evolutionary ecology — genetics and genomics, and theoretical ecology — modeling) contributions to contemporary investigation of the above theme. 'Model systems' dominating our literature survey were native Choristoneura fumiferana and invasive Lymantria dispar. These systems represent opposing ends of a more general equilibrium–disequilibrium...

Managing old-growth forests and promoting old-growth complexity in aging forests for carbon emissions mitigation has become an important component of diversified land management strategies. In the midwestern US, the Central Hardwoods Region (CHR) is the largest continuous deciduous forested area and includes a diverse range of species compositions, forest structures, and topoedaphic environments. Understanding carbon storage potential in old-growth forests across the CHR is important for evaluating climate-adaptive management strategies to increase carbon sequestration in the region’s...

Background: The Spanish region of Galicia is one of the most fire-prone areas in Europe. Most wildfires are directly or indirectly related to human activities, suggesting that socioeconomic factors likely can inform wildfire management. Socioeconomic factors, for example, could help explain the causes and distribution of wildfires spatially and temporally within the region. We sought to examine how socioeconomic and biophysical variables and their fluctuations over time (2000–2015) might influence wildfire ignitions and hectares burned in Galicia using municipality-level data describing...