Treesearch

To investigate how source and processing control the composition of “terrestrial” dissolved organic matter (DOM), we combine soil and tree leachates, tree DOM, laboratory bioincubations, and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry in three common landscape types (upland forest, forested wetland, and poor fen) of Southeast Alaska’s temperate rainforest. Tree (Tsuga heterophylla and Picea sitchensis) needles and bark and soil layers from each site were leached, and tree stemflow and throughfall collected to examine DOM sources. Dissolved organic...

Black ash wetlands cover approximately 1.2 million ha of wetland forest in the western Great Lakes region, providing critical habitat for wildlife. The future of these wetlands is critically threatened by a variety of factors, including emerald ash borer (Agrilus planipennis; emerald ash borer [EAB]), which has been eliminating native populations of otherwise healthy ash throughout the Great Lakes region since it was discovered in 2002. To quantify the potential impacts of tree mortality from EAB on wildlife communities, we measured seasonal bird, mammal, and amphibian diversity in black...

Climate warming and altered disturbance regimes are changing forest composition and structure worldwide. Given that species often exhibit individualistic responses to change, making predictions about the cumulative effects of multiple stressors across environmental gradients is challenging, especially in diverse communities. For example, warming temperatures are predicted to drive species upslope, whereas fire exclusion promotes the expansion of species at lower elevations where fire was historically frequent. We resampled 148 vegetation plots to assess 46 years (1969–2015) of species and...

Active forest management is applied in many parts of the western United States to reduce wildfire severity, mitigate vulnerability to drought and bark beetle mortality, and more recently, to increase snow retention and late-season streamflow. A rapidly warming climate accelerates the need for these restorative treatments, but the treatment priority among forest patches varies considerably. We simulated four treatment scenarios across the 3,450 km2 Wenatchee River basin in eastern Washington, United States. We used a decision support tool (DST) to assess trade-offs and synergies within and...

Forest biological disturbance agents (BDAs) are insects, pathogens, and parasitic plants that affect tree decline, mortality, and forest ecosystems processes. BDAs are commonly thought to increase the likelihood and severity of fire by converting live standing trees to more flammable, dead and downed fuel. However, recent research indicates that BDAs do not necessarily increase, and can reduce, the likelihood or severity of fire. This has led to confusion regarding the role of BDAs in influencing fuels and fire in fire-prone western United States forests. Here, we review the existing...

In contemporary forest landscapes, aquatic-riparian management approaches are addressing ecological integrity of site-to-landscape components that extend beyond the reach of traditional best management practices (BMPs). In this chapter, we highlight the intersection of BMPs that have guided past priorities with integrated interdisciplinary geomorphic, hydrologic, and biological perspectives of joint aquatic-terrestrial ecosystem management and restoration in forests. Beyond-BMP considerations include adapting prescribed BMPs for broader species and habitat protections and recognizing the...

Large in-stream wood (LW) is a critical component of riparian systems that increases heterogeneity of flow regimes and provides high quality habitat for salmonids and other fishes. We present four sampling-based methods to estimate two-dimensional LW for a 61-hectare river restoration project on the South Fork McKenzie River near Rainbow, OR (USA). We manually delineated LW area, from unoccupied aircraft systems (UAS) multispectral imagery for 40 randomly selected 51.46 m2 hexagonal plots. Seven auxiliary variables were extracted from the imagery and imagery derivatives to be incorporated...

Monitoring is usually among the first actions taken to help inform recovery planning for declining species, but these data are rarely used formally to inform conservation decision making. For example, Central Valley Chinook salmon were once abundant, but anthropogenic activities have led to widespread habitat loss and degradation resulting in significant population declines. Monitoring data suggest survival through the southern Sacramento-San Joaquin River Delta, in particular, may be a limiting factor for juvenile Chinook salmon outmigrating from the San Joaquin River and its tributaries....

The health benefits of exposure to trees and plants is a rapidly expanding field of study. Research has shown that exposure is associated with improvements in a wide range of health outcomes including cardiovascular disease, birth outcomes, respiratory disease, cancer, mental health and all-cause mortality1. One of the challenges that these studies face is characterizing participants’ exposure to trees and plants. A common approach is to use the normalized difference vegetation index, a greenness index typically derived from satellite imagery. Reliance on the normalized difference vegetatio...

Black spruce forest communities in boreal Alaska have undergone self-replacement succession following low-to-moderate severity fires for thousands of years. However, recent intensification of interior Alaska's fire regime, particularly deeper burning of the soil organic layer, is leading to shifts to deciduous dominated successional pathways, resulting in many socioecological consequences. Both fuel load quantity and quality (or “burnability”) influence black spruce plant communities' potential to burn. Even relatively low fuel loads, such as those seen in black spruce forest understory,...