Treesearch

Understanding how urban forests developed their current patterns of tree canopy cover, species composition, and diversity requires an appreciation of historical legacy effects. However, analyses of current urban forest characteristics are often limited to contemporary socioeconomic factors, overlooking the role of history. The institutions, human communities, and biophysical conditions of cities change over time, creating layers of legacies on the landscape, shifting urban forests through complex interactive processes and feedbacks. Urban green spaces and planted trees can persist long...

We examined how different landscape areas in a catchment containing a northern ombrotrophic peatland and upland mineral soils responded to dramatic decreases in atmospheric deposition of lead (Pb). Pb concentrations in the outflow stream from the peatland measured from 2009−2015 indicated continued mobilization and export of Pb derived from historic inputs to the bog. In contrast, Pb concentrations in surface peat and runoff from upland mineral soils have declined in response to reductions in atmospheric deposition. Relative to the early 1980s, Pb concentrations in the streamflow decreased...

This resource update provides an overview of forest resources in Michigan based on inventories conducted by the USDA Forest Service, Forest Inventory and Analysis (FIA) program of the Northern Research Station. Estimates are based on field data collected using the FIA annualized sample design and are updated yearly. The annual inventory started in 1999. For the 2017 inventory, estimates for current variables such as area, volume, and biomass are based on 6,647 plot samples collected from 2011 to 2017. Change variables, such as net growth, removals, and mortality, are based on 6,050 samples...

When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have...

Background: Knowledge of the different kinds of tree communities that currently exist can provide a baseline for assessing the ecological attributes of forests and monitoring future changes. Forest inventory data can facilitate the development of this baseline knowledge across broad extents, but they first must be classified into forest community types. Here, we compared three alternative classifications across the United States using data from over 117,000 U.S. Department of Agriculture Forest Service Forest Inventory and Analysis (FIA) plots.Methods: Each plot had three forest community...

Demographic processes (fecundity, dispersal, colonization, growth, and mortality) and their interactions with environmental changes are notwell represented in current climate-distribution models (e.g., niche and biophysical process models) and constitute a large uncertainty in projections of future tree species distribution shifts.We investigate how species biological traits and environmental heterogeneity affect species distribution shifts. We used a species-specific, spatially explicit forest dynamic model LANDIS PRO, which incorporates site-scale tree species demography and competition,...

We examined plant community organization over the first five growing seasons after clearcut harvesting with retention of two levels of logging debris (light and heavy) and application of four vegetation control treatments (non-sprayed control, aminopyralid (A), triclopyr (T), and A+T). Our study site was 44 km northwest of Olympia, WA., USA, and before forest harvesting it was dominated byPseudotsuga menziesii. We used a randomized split plot experimental design replicated in 6 blocks (each debris-treatment main plot had four herbicide-treatment split plots). We estimated percent canopy...

Legacies of social and environmental injustices can leave an imprint on the present and constrain transitions for more sustainable futures. In this article, we ask this question: What is the relationship of environmental inequality and histories of segregation? The answer for Baltimore is complex, where past practices of de jure and de facto segregation have created social and environmental legacies that persist on the landscape today. To answer this question, we examine the interactions among past and current environmental injustices in Baltimore from the late 1880s to the present using...

Wilderness management can be tricky. The conservationist Aldo Leopold, who is considered by many to be the father of wildlife ecology and the U.S. wilderness system, was probably thinking about this when he said, “All conservation of wildness is self-defeating, for to cherish we must Wilderness managers in North Cascades National Park opted for chemical treatments to remove invasive fish species. see and fondle, and when enough have seen and fondled, there is no wilderness left to cherish.”