Treesearch

Mixedwood forest composition, or co-dominance of hardwood and softwood species, has been interpreted as both stable and unstable. Through review of existing theory, we propose a conceptual model to understand mixedwood compositional stability in boreal and temperate forests of eastern North America. We first review the current theory that the strength of neighborhood effects (i.e., species ability to self-replace under their own canopy) is essential to understanding stability such that when self-replacement is strong for both dominant hardwood and softwood species, composition is stable...

Large multiobjective forest monitoring efforts such as the USDA’s Forest Inventory and Analysis Program and other National Forest Inventory (NFI) systems are usually described to the public in terms of the relationship of their sample designs to the land base of interest. Sometimes the third dimension of time is included in the description of the sample design. Additionally, there is a tendency to favor descriptions that arguably support design-based views of the used estimation systems. The accompanying justification usually relies on an assumption that design-based estimators are...

Unimodal response of tree species richness to increases in aboveground productivity is evident in grasslands but to a lesser extent in forests, where confounding factors (e.g., abiotic factors and management regimes) may alter the response and compromise the delivery of ecosystemservices.We hypothesize that unimodal response of biomass accumulation through increased species richness leads to greater tree above ground carbon (AGC) stocks and thus climate regulation but not necessarily higher timber volume production for human consumption across portions of North American and European...

Transporting firewood can spread plant pests such as the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), which was discovered in Lower Michigan, United States of America in 2002. In 2005, Michigan banned the transport of hardwood firewood northwards across the Mackinac Bridge, which connects Lower and Upper Michigan. In 2005–2011, 479 drivers of 11 commercial vehicles and 468 private vehicles were interviewed. Firewood was collected in every month of the year, with most firewood collected in June–September. Of the 468 private vehicles surveyed, 400 carried...

Rhinoncomimus latipes Korotyaev is a specialist biocontrol agent of mile-a-minute weed, Persicaria perfoliata (L.) H. Gross (Caryophyllales: Polygonaceae). Currently, R. latipes is released by hand where the presence of the weed is readily detected. However, the hand-release method is not applicable to weed patches spread in hard-to-access areas. This study was conducted to develop a spatially targeted biocontrol strategy by using an unmanned aircraft system (UAS, a.k.a. drone) for the detection of P. perfoliata and aerial release of R. latipes. A ground survey was performed to locate P....

Organic matter (OM) is an integral part of site productivity for a forest, and understanding the effects of OM removal on various forms of carbon (C) cycling is important for land managers and for policy makers. In this study, we utilized the Lake States Long-Term Soil Productivity (LTSP) study sites, located along a gradient in soil texture (clay, silt loam and sand) and high to low productivity, to evaluate the impacts of two OM removal treatments on belowground wood decomposition. In 2013, approximately 20 years after the LTSP treatments had been installed, we placed standardized aspen...

Invasive insects and pathogens are prominent tree mortality agents in forests around the world, and the magnitude of their impacts is increasing. Comparative studies across multiple populations can be helpful for the development of new insights and innovative management strategies. We used the Sirex woodwasp, Sirex noctilio Fabricius, as a model system to compare invasion impacts across a range of ecological contexts around the globe: native woodwasps colonizing native trees, invasive woodwasps in non-native plantation trees, and invasive woodwasps attacking native trees. Across 133 stands...

Reconstructing the geographic origins of non-native species is important for studying the factors that influence invasion success, however; these analyses can be constrained by the amount of diversity present in the native and invaded regions, and by changes in the genetic background of the invading population following bottlenecks and/or hybridization events. Here we explore the geographical origins of the invasive winter moth (Operopthera brumata L.) that has caused widespread defoliation to forests, orchards, and crops in Nova Scotia, British Columbia, Oregon, and the northeastern...

Proper understanding of the diversity and natural structure of woody species and the impacts of human interventions are prerequisites for maintaining the remaining forests as well as restoration of deforested and degraded areas. This research was conducted to document the impact of human interventions on the population structure and the species diversity in the Arasbaran biosphere reserve in Iran due to the limited research and insufficient knowledge. The study area was divided into three adjacent sampling areas of low, medium, and high destruction intensity. Thirty fixed area 0.1-hectare...

We compiled data from several independent, long-term silvicultural studies on USDA Forest Service experimental forests across a latitudinal gradient in the northeastern and north-central U.S.A. to evaluate factors influencing aboveground live-tree carbon sequestration and mortality. Data represent five sites with more than 70,000 repeated tree records spanning eight decades, five ecoregions, and a range of stand conditions. We used these data to test the relative influence of factors such as climate, treatment history (uneven-aged or no management), species composition, and stand structural...