Treesearch

Most recent implementations of low-cost electrical conductivity (EC) sensors intended for water quality measurements are based on simple two-pole designs. However, in marine settings, EC often exceeds the range where two-pole sensors provide reliable results. We have developed a simple four-pole EC sensor that relies exclusively on analog-to-digital measurements made using readily available circuit boards (pyboard v.1.1 or Raspberry Pi Pico 2040) programmed using MicroPython. Other than resistors and graphite or wire electrodes, no other electronic components are required for the EC...

Models that assess the vulnerability of freshwater species to shifting environmental conditions do not always account for short-duration extremes, which are increasingly common. Life cycle models for Pacific salmon (Oncorhynchus spp.) generally focus on average conditions that fish experience during each life stage, yet many floods, low flows, and elevated water temperatures only last days to weeks. We developed a process-based life cycle model that links coho salmon (Oncorhynchus kisutch) abundance to daily streamflow and thermal regimes to assess: (1) “How does salmon abundance respond...

Meltwater contributions to watersheds are shrinking as glaciers disappear, altering the flow, temperature, and biogeochemistry of freshwaters. A potential consequence of this landscape change is that streamflow patterns within glacierized watersheds will become more homogenous, potentially altering the capacity of watersheds to support Pacific salmon. To assess heterogeneity in stream habitat quality for juvenile salmon in a watershed in the Alaska Coast Mountains, we collected organic matter and invertebrate drift and measured streamwater physical and biogeochemical properties over the...

California contains a diverse flora, and knowledge of the pathogens that threaten those plants is essential to managing their long-term health. To better understand threats to California plant health, a meta-analysis of Phytophthoradetections within the state was conducted using publicly available sequences as a primary source of data rather than published records. Accessions of internal transcribed spacer (ITS) ribosomal DNA were cataloged from 800 Californian Phytophthoraisolates, analyzed, and determined to correspond to 80 taxa, including several phylogenetically distinct provisional...

Mechanical forest thinning treatments are implemented across the western United States (US) to improve forest health and reduce hazardous fuels. However, the main challenge in thinning operations is low financial feasibility. This study synthesized the stump-to-truck cost of forest thinning operations in the western US based on operations research articles published over the last 40 years (1980-2020). We systematically selected and reviewed 20 thinning studies to analyze key variables affecting machine productivity and harvesting costs. The average cost of forest thinning was lowest for a...

Based on current trends and policies aimed at decarbonizing energy systems, the conversion of biomass to bioenergy has the potential to grow rapidly, but such growth depends on the development of efficient, sustainable, and competitive biomass supply chains. As a result, the biomass supply chain has stimulated the interest of a diverse group of researchers across academia, government, and industry, and there is a need to synthesize and categorize the rapidly expanding literature in this field. We conducted a literature review using advanced bibliometric analysis and visualization of 1711...

The effects of hurricanes Irma and Maria and a severe drought on the temperature, precipitation,and soil moisture (under canopy and in the open) were calculated at 22 sites from 0–1045m in northeastern Puerto Rico from 2001–2021, against the background short-term trend. Medianand minimum air temperatures increased uniformly across the elevational gradient, 1.6 times as fastin the air under the canopy (+0.08 °C/yr) and 2.2 times as fast in the soil under the canopy (+0.11°C/yr) as for air temperature in the open. There were no substantial moisture trends (average decrease<0.01 mm/yr). The...

Long-term trends show increased tree mortality over the last several decades, coinciding with above-average temperatures, high climatic water deficits, and bark beetle outbreaks. California’s recent unprecedented drought (2012–2016) highlights the need to evaluate whether thinning and prescribed fire can improve individual tree drought resistance and reduce bark beetle-associated mortality. Using a thinning and prescribed fire study on the Stanislaus-Tuolumne Experimental Forest in the central Sierra Nevada implemented prior to the drought (2011–2013), we used dendrochronological methods...

Releasing several ecotypes or species of biological control agent is common in many biological control programs. However, the consequences of hybridization for fitness and host use of the resulting hybrids are difficult to predict, especially for hybrids between more than two species and with varying levels of introgression. Hybridization of biocontrol agents may increase or decrease fitness, with consequences for control efficacy. Additionally, hybridization may lead to changes in host use patterns that may put non-target host species at increased risk. We collected genomic data to...

Although recent large wildfires in California forests are well publicized in media and scientific literature, their cumulative effects on forest structure and implications for forest resilience remain poorly understood. In this study, we evaluated spatial patterns of burn severity for 18 exceptionally large fires and compared their cumulative impacts to the hundreds of smaller fires that have burned across California forests in recent decades. We used a burn severity atlas for over 1,800 fires that burned in predominantly conifer forests between 1985 and 2020 and calculated landscape...