Treesearch

Developing and implementing landscape-scale management strategies capable of balancing the need for restoring natural fire regimes and promoting ecosystem resiliency for future climate change remains an urgent need globally. To help guide development of a landscape management strategy capable of meeting multiple objectives, five alternative landscape management scenarios for reducing the risk of uncharacteristically severe wildfire using thinning or managed and prescribed wildfire were developed by local forest managers in the Lake Tahoe region of the Sierra Nevada mountains. Effects of...

Water management in snowy mountainous regions hinges on forecasting snowmelt runoff. However, droughts are altering snowpack-runoff relationships with ongoing debate about the driving mechanisms. For example, in 2021 in California, less than half of predicted streamflow arrived. Mechanisms proposed for this “missing” streamflow included changes in evapotranspiration (ET), rainfall, and subsurface moisture conditions. Here, we demonstrate that ETin drought years generates dry subsurface conditions that reduce runoff in subsequent years. A model including this legacy of depleted moisture...

Deviations in hydrologic processes due to wildfire can alter streamflows across the hydrograph, spanning peak flows to low flows. Fire-enhanced changes in hydrologic processes, including infiltration, interception, and evapotranspiration, and the resulting streamflow responses can affect water supplies, through effects on the quantity, quality, and timing of water availability. Post-fire shifts in hydrologic processes can also alter the timing and magnitude of floods and debris flows. The duration of hydrologic deviations from a pre-fire condition or function, sometimes termed hydrologic...

Large wood (LW) influences geomorphic and ecological processes. However, most field data sets describing LW dynamics are conducted over the span of only a few years. We present a unique long-term data set from northern California, USA of LW volumes, inputs, and transport in two small headwater streams, the North Fork (NF) and South Fork (SF) of Caspar Creek. We used data collected approximately every 2 years from 1998 to 2018 to assess how LW budgets change over time between catchments, what factors influence inputs from standing trees to the streams, and controls on LW piece mobility. We...

Wildfires play an important ecological role in fire-adapted landscapes throughout California. However, there is a growing awareness that large wildfires in increasingly populated areas incur costs that may not be acceptable to society. Various forest management strategies have been proposed that seek to reduce the prevalence and severity of wildfires in areas where these costs are high. In this study we estimate the financial costs of various hypothetical forest management scenarios in the Lake Tahoe West landscape of Northern California. The objective of the study was to quantify trade-off...

The invasive shrub Scotch broom (Cytisus scoparius(L.) Link) is a pervasive threat to regenerating Douglas-fir (Pseudotsuga menziesii(Mirb.) Franco var. menziesii) stands in the Pacific Northwest, USA. Field observations indicate that the susceptibility of areas to Scotch broom invasion and dominance can vary by site. We selected 10 sites throughout the western Pacific Northwest that spanned a gradient of soil textures and other factors to test the site-specific susceptibility of Douglas-fir to overtopping by Scotch broom. We expected to find that the ability of Scotch broom to dominate a...

Background: Fire models use pyrolysis data from ground samples and environments that differ from wildland conditions. Two analytical methods successfully measured oxidative pyrolysis gases in wind tunnel and field fires: Fourier transform infrared (FTIR) spectroscopy and gas chromatography with flame-ionisation detector (GC-FID). Compositional data require appropriate statistical analysis. Aims: To determine if oxidative pyrolysis gas composition differed between analytical methods and locations (wind tunnel and field). Methods: Oxidative pyrolysis gas sample composition collected in wind...

The continuity and depth of the surface litter and duff layers are major drivers of fire spread and fuel consumption. Nevertheless, its spatially explicit quantification over relatively large areas remains unresolved: local fuel heterogeneity introduces large uncertainties in estimates derived from field-based models and sparse data samples. Besides that, the sensitivity of remote sensors to surface litter loads is limited, particularly under canopy cover. In fire-maintained pine forests of the Southeastern US, surface fuel accumulation and its distribution over the forest floor are mainly...