Treesearch

We hypothesize that lower public visibility of residential backyards reduces households’ desire for social conformity, which alters residential land management and produces differences in ecological composition and function between front and backyards. Using lawn vegetation plots (7 cities) and soil cores (6 cities), we examine plant species richness and evenness and nitrogen cycling of lawns in Boston, Baltimore, Miami, Minneapolis-St. Paul, Phoenix, Los Angeles (LA), and Salt Lake City (SLC). Seven soil nitrogen measures were compared because different irrigation and fertilization...

Purpose: Wildfire spatial patterns drive ecological processes including vegetation succession and wildlife community dynamics. Such patterns may be changing due to fire suppression policies and climate change, making characterization of trends in post-fire mosaics important for understanding and managing fire-prone ecosystems.Methods: For wildfires in California’s yellow pine and mixed-conifer forests, spatial pattern trends of two components of the post-fire severity matrix were assessed for 1984-2015: (1) unchanged or very low-severity and (2) high-severity, which represent remnant...

Energy flow through ecosystems plays a critical role in processes at multiple spatial and temporal scales, from phonologically driven growing season or monthly temporal scales of landscapes to sub-diurnal responses of soil respiration to temperature, photosynthesis and water inputs. The interaction of short and longwave radiation and their partitioning through ecosystems is complex with terrestrial canopies and aquatic structure both connecting above- and below-ground processes via energy fluxes. Previous work has shown that at 30-min timescales, only 8% of eddy covariance sites in the La...

In recent years, the field of wildfire risk management has seen dramatic advances. One notable improvement is in the realm of pre-fire suppression response planning, in particular the expansion from the assessment of risks posed by fire to the assessment of opportunities to effectively manage fire. Such proactive assessment and planning is critical to ensure that suppression response strategies and tactics are more likely to be safe and efficient. In this paper we will review the state-of-the-art in wildfire suppression planning, and illustrate application of advanced planning tools on a...

Climate change is increasing the intensity of severe tropical storms and cyclones (also referred to as hurricanes or typhoons), with major implications for tropical forest structure and function. These changes in disturbance regime are likely to play an important role in regulating ecosystem carbon (C) and nutrient dynamics in tropical and subtropical forests. Canopy opening and debris deposition resulting from severe storms have complex and interacting effects on ecosystem biogeochemistry. Disentangling these complex effects will be critical to better understand the long-term implications...

Data uncertainty due to spatial gaps and heterogeneity is a fundamental problem in conservation and environmental planning. Thus, investigation of issues related to data uncertainty contributes to more efficient conservation plans. We evaluated the uncertainty of data related to forest diversity descriptors using a diffusionbased cartogram approach that visually displays how data information change in function with respect to degree of uncertainty. We used ground vegetation data for 3093 plots collected as part of the BioSoil project through the ICP Forests Level I network and stored in...

Droughts of the twenty-first century are characterized by hotter temperatures, longer duration, and greater spatial extent, and are increasingly exacerbated by human demands for water. This situation increases the vulnerability of ecosystems to drought, including a rise in drought-driven tree mortality globally (Allen et al. 2015) and anticipated ecosystem transformations from one state to another—for example, forest to a shrubland (Jiang et al. 2013). When a drought drives changes within ecosystems, there can be a ripple effect through human communities that depend on those ecosystems for...

Few ash trees (Fraxinus spp.) have survived the initial devastation that emerald ash borer beetle (EAB) (Agrilus planipennis) has caused in natural populations. We studied green ash (Fraxinus planipennis) trees in a floodplain population after >90% of ash had died from EAB infestation. We examined the relationship among the canopy health classes of surviving ash trees and their nearest neighboring trees (within 6 m) and available soil nutrients. A subset of focal ash trees was randomly selected within health classes ranging from healthy to recently deceased. Focal trees with the healthiest...

En Colorado, los bosques secos de coníferas mixtas de la Cordillera frontal han sufrido un cambio radical. A mediados de los 1800, los bosques de la Cordillera frontal eran más abiertos y herbáceos, y los rodales eran de dos a tres veces menos densos. Había árboles de todas las clases de tamaño en una disposición “agrupada”, en la que los grupos de árboles estaban separados por aperturas de un acre o menos. A nivel del paisaje, existía un rico mosaico paisajístico con bosques maduros de edad desigual mantenidos por incendios de baja gravedad, entremezclados con parches de bosque de...

Live fuel, on average, was the most important factor driving high-severity fire in and among ecoregions. Fire weather was the second most important factor, followed by climate and topography. Recently published ecoregional wall-to-wall gridded maps, based on satellite imagery that characterizes live fuel, are available to help land managers in the western United States identify areas with a high probability of high-severity fire.