Treesearch

Family forest landowners in the United States have diverse ownership and management objectives. Assessing and monitoring regional patterns and trends in landowner motivations and management behavior may aid in understanding the conservation and economic implications of social change. This paper presents a regional analysis of family forest landowners in the southern United States by combining a GIS-based exploratory data analysis with spatially explicit information on landowner motivations and management behavior data obtained from the U.S. Forest Service National Woodland Owners Survey...

Oak decline was the focus of the last Oak Symposium in 2002. Since then, in the Ozark Highlands and considering the red oak group alone, more than 60 percent of the forest has been severely impacted by oak decline. This is a synthesis of our past 15 years of research into oak decline. Our methods included inventories and/or modeling at seedling, forest stand, landscape, and regional scales. Within 1 year of decline onset, a stand scale study showed the number of standing dead northern red oak (Quercus rubra L.) trees increased by 55 percent (P-value = 0.029). Within the Ozark Highlands,...

Successional tree species often form soil seedbanks, suggesting that extended seed dormancy may also facilitate regeneration in nonnative species. We examined seed dormancy in Ailanthus altissima, which is currently spreading into long-established forests of Europe and eastern North America. Ailanthus seeds were sewn into replicated nylon mesh bags and buried in 10 second-growth stands in southeast Ohio, USA. North- and south-facing slopes were included as a coarse-grained test for environmental control. Bags were recovered at 2-mo intervals and seeds were tested for viability and germinati...

Despite reported health benefits of urban greenspace (gs), the epidemiological evidence is less clear for allergic disease. To address a limitation of previous research, we examined the associations of medium- and high-resolution residential gs measures and tree and/or grass canopies with allergic outcomes for children enrolled in the longitudinal cincinnati childhood allergy and air pollution study (ccaaps). We estimated residential gs based on 400 m radial buffers around participant addresses (n=478) using the normalized differential vegetation index (ndvi) and land cover-derived urban...

Winter is an important period for ecological processes in northern regions; however, compared to other seasons, the impacts of winter climate on ecosystems are poorly understood. In this review we evaluate the influence of winter climate on carbon dynamics based on the current state of knowledge and highlight emerging topics and future research challenges. Studies that have addressed this topic include plot-scale snow cover manipulation experiments that alter soil temperatures, empirical investigations along natural climatic gradients, laboratory temperature incubation experiments aimed at...

Epidemiological models are powerful tools for evaluating scenarios and visualizing patterns of disease spread, especially when comparing intervention strategies. However, the technical skill required to synthesize and operate computational models frequently renders them beyond the command of the stakeholders who are most impacted by the results. Participatory modelling (PM) strives to restructure the power relationship between modellers and the stakeholders who rely on model insights by involving these stakeholders directly in model development and application; yet, a systematic literature...

Forest ecosystems have been increasingly affected by a variety of disturbances, including emerging infectious diseases (EIDs), causing extensive tree mortality in the Western United States. Especially over the past decade, EID outbreaks occurred more frequently and severely in forest landscapes, which have killed large numbers of trees. While tree mortality is observable from remote sensing, its symptom may be associated with both disease and non-disease disturbances (e.g., wildfire and drought). Species distribution modeling is widely used to understand species spatial preferences for...

Phytophthora ramorum, cause of sudden oak death, has been distributed widely across the United States in horticultural situations, but is not established in forests outside of California and Oregon. Here, it has triggered widespread concern and, especially in Oregon, an intensive disease management programme. Now, we provide the first systematic evaluation of the efficacy of that effort. This paper evaluates four measures of the efficacy of Sudden Oak Death (SOD) local eradication treatments: inoculum availability; inoculum from tree species other than tanoak; disease spread from treated...

Predicting bedload transport rates is useful for many reasons, but accurate predictions are difficult to make. At the Caspar Creek Experimental Watersheds, a long-term monitoring site in a coast redwood forest in northern California, we wish to know how bedload transport responds to logging and sediment input such as landslides. To complete such analysis requires being able to accurately measure and predict bedload transport yields. Here, we focus on developing an approach to reconstruct an 18-year record of annual bedload yields for the North Fork of Caspar Creek and compare the reconstruc...

Over the last two decades we have made considerable progress on understanding and predicting the effects of wildfires on runoff and erosion at the hillslope scale. One cannot, however, sum up the hillslope-scale effects to predict what happens downstream because of the scale-dependent changes in the driving variables and controlling processes; yet resource managers need an understanding and predictive capability to assess post-fire risks at watershed scales, and to prioritize post-fire treatments among watersheds and fires. As watershed size continues to increase the risks of downstream...