Treesearch

Mountain headwater streams have emerged as important climate refuges for native cold-water species due to their slow climate velocities and extreme physical conditions that inhibit non-native invasions. Species persisting in refuges often do so as fragmented, relict populations from broader historical distributions that are subject to ongoing habitat reductions and increasing isolation as climate change progresses. Key for conservation planning is determining where remaining populations will persist and how habitat restoration strategies can improve biological resilience to enhance the...

The management of low-density savannah and woodland forests for carbon storage presents a mechanism to offset the expense of ecologically informed forest management strategies. However, existing carbon monitoring systems draw on vast amounts of either field observations or aerial light detection and ranging (LiDAR) collections, making them financially prohibitive in low productivity systems where forest management focuses on promoting resilience to disturbance and multiple uses. This study evaluates how UAS altitude and flight speed influence area-based aboveground forest biomass model...

High-elevation five-needle pines are foundational species and iconic components of subalpine forests across western North America. Because they often grow at environmental extremes, high-elevation pines are vulnerable to changing climate conditions. In addition to the direct effects of recent climatic changes, these species are increasingly threatened by biotic disturbances that thrive in the warming and drying conditions now occurring at higher elevations. Among the high-elevation pines, Great Basin bristlecone pine (Pinus longaeva) is revered for its extreme longevity and has been...

Composition of pyrolysis gases for wildland fuels is often determined using ground samples heated in non-oxidising environments. Results are applied to wildland fires where fuels change spatially and temporally, resulting in variable fire behaviour with variable heating. Though historically used, applicability of traditional pyrolysis results to the wildland fire setting is unknown. Pyrolytic and flaming combustion gases measured in wind tunnel fires and prescribed burns were compared using compositional data techniques. CO2was dominant in both. Other dominant gases included CO, H2and CH4....

In forests where the overstorey canopy has been disturbed by timber harvest or other means, evapotranspiration (ET) by the understorey may be the main flux of water back to the atmosphere. However, little research has been apportioned to directly measuring understorey water use, and the technology to do so is thus limited. Here, we used a portable chamber to quickly and directly measure understorey ET by measuring the water flux from the soil and vegetation enclosed by the chamber. This method was used in a third-growth coast redwood forest to measure ET rates from individuals of five...

November month-over-month and year-over-year housing data were primarily positive. Only single-family housing completions were negative month-over-month. Single-family starts, permits, completions and new sales were negative year-over-year. Single-family permits and starts, total housing completions, and new and existing house sales were negative year-over-year. Existing house sales also were negative year-over-year. Completions continue to be restrained due to the unavailability of building materials and products, combined with other factors. Thus, certain builders may be reluctant to...

The month-over-month and year-over-year housing data for October were mostly positive. Total and single-family starts and single-family housing completions were negative month-over-month. Single-family permits and starts, total housing completions, and new and existing house sales were negative year-over-year. Currently there are more multifamily units under construction than at any time over the past 47 years. Completions remained restrained due to the unavailability of building materials and products, among other factors. Thus, certain builders may be reluctant to start new projects...

Effects of historical fire suppression in forested ecosystems, combined with increasingly frequent and prolonged periods of drought due to a changing climate, are predicted to drive increases in the extent and intensity of wildfires in western North America and elsewhere. Understanding the effects of wildfires on forest-dependent species and interactions among species is important for conservation and management decisions. We used data collected from a long-term carnivore monitoring program in northern California and southern Oregon, USA to investigate the effects of three mixed-severity...

Salmon are iconic keystone species across the northern Pacific and Atlantic basins. Salmon is also a prized human delicacy. Wild salmon populations have been decimated by a combination of overharvesting, dams, and water diversions. Efforts to increase salmon abundance through fish farming and hatcheries have failed to stem the decline, instead exposing wild populations to diseases, pests, and the debilitating genetic effects of interbreeding with partially domesticated farm escapees and hatchery releases (1). For additional information on this publication, please see this ITIF blog:...

Wildfire-burnt hillslopes are vulnerable to erosion, precipitation-induced landslides, and debris flows. Xanthan gum (XG) and polyacrylamide (PAM) were recently shown as attractive alternatives for controlling surface erosion. However, their mobility on the hillslopes or effects on downstream waters are unknown. This study showed that after three wet-dry cycles, vertical movement of XG and PAM into the soil with rainfall is possible. Controlled water quality experiments showed that XG could have negative impacts on acidity and turbidity if its concentration in water is 0.25% or higher....