Treesearch

Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated...

Albedo products from the MODerate resolution Imaging Spectroradiometer (MODIS) have been validated extensively over spatially homogeneous siteswith snow-cover. This study evaluated the spatial scaling of albedo and related reflectance-based quantities over areas of high spatial heterogeneity in temperate mixed forest, deciduous forest, urban and built-up, and cropland/natural mosaic lands under snow covered conditions. Reflectance-based quantities evaluated included spectral radiance, surface directional reflectance, and spectral and broadband albedo derived from ground- and tower-based...

Key message. Knowing the uncertainty for biomass equations is critical for their use and error propagation of biomass estimates. Presented here is a method to estimate uncertainty for equations where only n and R2 values from the original equations are available. Context. Tree allometric equations form the basis of research and assessments of forest biomass. Frequently, uncertainty estimations do not propagate errors from these equations since the necessary information about sampling and tree measurements is not included in the original publication. Many biomass studies were conducted...

High-latitude regions are experiencing rapid and extensive changes in ecosystem composition and function as the result of increases in average air temperature. Increasing air temperatures have led to widespread thawing and degradation of permafrost, which in turn has affected ecosystems, socioeconomics, and the carbon cycle of high latitudes. Here we overcome complex interactions among surface and subsurface conditions to map nearsurface permafrost through decision and regression tree approaches that statistically and spatially extend field observations using remotely sensed imagery,...

Forest carbon management is an important consideration in temperate forests as well as tropical and boreal forest biomes. It is estimated that US forests absorb 10-20 percent of total US carbon dioxide emissions, or more than 200 Tg C yr-1. Recent research suggests that this net carbon sink is likely to decline over the next few decades, and that US forests could become a net carbon source unless decisive action is taken in the near term to alter this trajectory. This paper will summarize ongoing research to determine how carbon management can be made compatible with existing sustainable...

To many woodland owners “harvesting” typically means the removal of timber from forests. In recent years many landowners have become aware of the role non-timber forest products (NTFPs) can play in supplemental management strategies to produce income while preserving other forest qualities. NTFPs are a diverse group of craft, culinary, and medicinal products that have been traditionally harvested from the wild, but can be intentionally managed or cultivated on forestland. Cultivation on managed lands, in contrast with wild harvesting or wildcrafting, can help to meet landowner production...

A large and growing body of evidence has demonstrated that airborne scanning light detection and ranging (lidar) systems can be an effective tool in measuring and monitoring above-ground forest tree biomass. However, the potential of lidar as an all-round tool for assisting in assessment of carbon (C) stocks in soil and non-tree vegetation components of the forest ecosystem has been given much less attention. Here we combine the use airborne small footprint scanning lidar with fine-scale spatial C data relating to vegetation and the soil surface to describe and contrast the size and...

Large trees are important and unique organisms in forests, providing ecosystem services including carbon dioxide removal from the atmosphere and long-term storage. Some reports have raised concerns about the global decline of large trees. Based on observations from two regions in Finland and three regions in the United States we report that trends of large trees during recent decades have been surprisingly variable among regions. In southern Finland, the growing stock volume of trees larger than 30 cm at breast height increased nearly five-fold during the second half of the 20th century,...

Marketing carbon offset credits generated by urban forest projects could help cities and local governments achieve their financial self-sufficiency and environmental sustainability goals. Understanding the value of carbon credits sourced from urban forests, and the factors that determine buyers’ willingness to pay a premium for such credits could benefit cities in strategically marketing carbon credits to generate revenue. This study surveyed business organisations participating in carbon trading in order to explore the factors influencing buyers’ willingness to pay for urban forest carbon...

A growing body of research has documented positive relationships among youth physical activity levels and park use. However, most investigations to date have focused on municipal parks, and relatively little is known about the physical activity levels of racially and ethnically diverse populations of youth using different types of parks in non-urban settings. This exploratory case study addressed these resaarch gaps by examining the influence of non-urban state parks on the physical activity of youth in northern Georgia.