Forests and Water Yield: A Synthesis of Disturbance Effects on Streamflow and Snowpack in Western Coniferous Forests

Journal of Forestry, Journal Year: 2020, Volume and Issue: 118(2), P. 172 - 192

Published: Feb. 12, 2020

Abstract In coniferous western forests, recent widespread tree mortality provided opportunities to test the long-held theory that forest cover loss increases water yield. We reviewed 78 studies of hydrologic response standing-replacing (severe wildfire, harvest) or nonstand-replacing (drought, insects, low-severity wildfire) disturbances, and reassessed question: Does yield snowpack increase after disturbance? Collective results indicate postdisturbance streamflow may increase, not change, even decrease, illuminate factors help improve predictability disturbance. Contrary expectation reduces evapotranspiration, making more available as runoff, evapotranspiration sometimes increased—particularly following disturbance—because (a) increased evaporation resulting from higher subcanopy radiation, (b) transpiration rapid growth. Postdisturbance depends on vegetation structure, climate, topography, new hypotheses continue be formulated tested in this rapidly evolving discipline.

Language: Английский

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The changing water cycle: The eco‐hydrologic impacts of forest density reduction in Mediterranean (seasonally dry) regions

Wiley Interdisciplinary Reviews Water, Journal Year: 2019, Volume and Issue: 6(4)

Published: May 7, 2019

Abstract In seasonally dry Mediterranean regions, forest ecosystems are well adapted to water stress. However, extended droughts, or droughts that warmer more frequent than they have been in the past, can large consequences on availability, productivity, and mortality. Forest density reduction offers a strategy for potentially mitigating these effects may not only improve health but also increase streamflow. While recent focused attention strategies, there is great uncertainty how changing structure alters availability both remaining trees downslope provision, particularly during semi‐arid forests. To help disentangle sometimes conflicting findings from case studies, we present review an eco‐hydrologic perspective considers much use (hydrology) affects ecophysiology (ecology). This helps build conceptual model of mechanisms through which changes composition influence mortality patterns, Mediterranean‐climate after droughts. Ultimately, this guide assessing when where will be likely achieve desired management objectives. article categorized under: Human Water > Governance Rights Science Quality

Language: Английский

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Development of a multi-objective decision support system for eco-hydrological forest management that quantifies and optimizes ecosystem services related to Carbon, Water, Fire-risk and Eco-resilience (CAFE)

Journal of Environmental Management, Journal Year: 2025, Volume and Issue: 380, P. 125103 - 125103

Published: April 1, 2025

Language: Английский

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Restoring Historic Forest Disturbance Frequency Would Partially Mitigate Droughts in the Central Sierra Nevada Mountains

Water Resources Research, Journal Year: 2025, Volume and Issue: 61(4)

Published: April 1, 2025

Abstract Forest thinning and prescribed fire are expected to improve the climate resilience water security of forests in western U.S., but few studies have directly modeled hydrological effects multi‐decadal landscape‐scale forest disturbance. By updating a distributed process‐based model (DHSVM) with vegetation maps from ecosystem (LANDIS‐II), we simulate resource impacts management scenarios targeting partial or full restoration pre‐colonial disturbance return interval central Sierra Nevada mountains. In fully restored regime that includes fire, thinning, insect mortality, reservoir inflow increases by 4%–9% total 8%–14% dry years. At sub‐watershed scales (10–100 km 2 ), dense can increase streamflow >20% thinner forest, increased understory transpiration compensates for decreased overstory transpiration. Consequentially, 73% gains attributable rain snow interception loss. Thinner headwater peak flows, reservoir‐scale flows almost exclusively influenced climate. Uncertainty future precipitation causes high uncertainty yield, additional yield is about five times less sensitive annual uncertainty. This decoupling response makes especially valuable supply during Our study confidence benefits restoring historic frequencies mountains, our modeling framework widely applicable other forested mountain landscapes.

Language: Английский

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Stand density effects on carbon and water fluxes in a semi-arid forest, from leaf to stand-scale

Forest Ecology and Management, Journal Year: 2019, Volume and Issue: 453, P. 117573 - 117573

Published: Sept. 12, 2019

Language: Английский

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Estimating evapotranspiration change due to forest treatment and fire at the basin scale in the Sierra Nevada, California

Ecohydrology, Journal Year: 2018, Volume and Issue: 11(7)

Published: April 9, 2018

Abstract We investigated the potential magnitude and duration of forest evapotranspiration (ET) decreases resulting from forest‐thinning treatments wildfire in west‐slope watersheds Sierra Nevada range California, USA, using a robust empirical relation between Landsat‐derived mean‐annual normalized difference vegetation index (NDVI) ET measured at flux towers. Among treatments, minimum observed NDVI change required to produce significant departure control plots with about 0.70 was −0.09 units, corresponding basal‐area reduction 29.1 m 2 /ha (45% reduction) equivalent an estimated 153 mm/year (21% change; approximate mean annual precipitation = 1,000 mm). Intensive thinning highly productive forests that approached prefire‐exclusion densities reduced basal area by 40–50%, generating reductions 153–218 (21–27% change) over 5 years following treatment. Low‐intensity underburn resulted no ET. Examining cumulative impact wildfires on 1990 2008, we found lower wetter American River basin (5,310 km ) generated more than twice per unit those higher drier Kings (4,790 ), greater water energy limitations latter fire severity former. A rough extrapolation these results entire watershed suggests due could approach 10% full natural flows for dry 5% all years.

Language: Английский

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Evapotranspiration Mapping for Forest Management in California's Sierra Nevada

Frontiers in Forests and Global Change, Journal Year: 2020, Volume and Issue: 3

Published: June 30, 2020

We assessed the response of densely forested watersheds with little apparent annual water limitation to forest disturbance and climate variability, by studying how past wildfires changed evapotranspiration what patterns imply for availability subsurface storage drought resistance. determined spatial using a top-down statistical model, correlating measured from eddy-covariance towers across California NDVI (Normalized Difference Vegetation Index) satellite, precipitation. The study area was Yuba American River watersheds, two in northern Sierra Nevada. Wildfires 1985-2015 period resulted significant post-fire reductions at least 5 years, some cases more than 20 years. levels biomass removed medium-intensity fires (25-75% basal loss), similar magnitudes expected treatments fuels reduction health, reduced as much 150-200 mm yr-1 first Rates recovery post-wildfire confirm need follow-up intervals 5-20 years sustain lower evapotranspiration, depending on local landscape attributes interannual climate. Using metric cumulative precipitation minus (P-ET) during multi-year dry periods, we found that forests showed evidence moisture stress 1985-2018 our analysis, owing relatively small reliance meet dry-year needs vegetation. However, more-severe or sustained periods will push lower-elevation studied toward P-ET thresholds previously associated widespread mortality southern

Language: Английский

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Wildfire controls on evapotranspiration in California’s Sierra Nevada

Journal of Hydrology, Journal Year: 2020, Volume and Issue: 590, P. 125364 - 125364

Published: Aug. 3, 2020

Language: Английский

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Restoring a Natural Fire Regime Alters the Water Balance of a Sierra Nevada Catchment

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(7), P. 5751 - 5769

Published: June 26, 2019

Abstract Fire suppression in western U.S. mountains has caused dense forests with high water demands to grow. Restoring natural wildfire regimes these could affect hydrology by changing vegetation composition and structure, but the specific effects on balance are unknown. Mountain watersheds supply much of United States, so understanding relationship between fire regime yield is essential inform management. We used a distributed hydrological model quantify hydrologic response restored Illilouette Creek Basin (ICB) within Yosemite National Park, California. Over past 45 years, as successive fires reduced ICB's forest cover approximately 25%, results show that annual streamflow, subsurface storage, peak snowpack increased relative fire‐suppressed control, while evapotranspiration climatic deficit decreased. A second experiment compared ICB under two scenarios: 2012 vegetation, representing frequent‐fire landscape, 1969 suppression. These landscapes were run observed weather data from 1972 2017 order capture variations precipitation temperature. This showed wet years experienced greater fire‐related reductions increases dry years. Spring snowmelt runoff was higher burned conditions, summer baseflow relatively unaffected. likely downstream availability, shifted streamflows slightly earlier, stress forests.

Language: Английский

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Plant Accessible Water Storage Capacity and Tree-Scale Root Interactions Determine How Forest Density Reductions Alter Forest Water Use and Productivity

Frontiers in Forests and Global Change, Journal Year: 2019, Volume and Issue: 2

Published: July 5, 2019

Forest disturbances such as wildfire and drought-related disease often lead to declines in productivity that both influence are influenced by forest water use, particularly the semi-arid environments of Western US. Fuel treatments frequently proposed reduce vulnerability these impacts some cases an approach increase yield. By changing ecosystem structure, fuel alter function (including hydrologic cycling, carbon sequestration, energy partitioning biogeochemical cycling). Empirical studies either through active management or natural disturbances, show a wide range responses include increases decreases use. Variation climate species, well magnitude density reduction, commonly explanations for this variation. In paper we use coupled eco-hydrologic model demonstrate subsurface features likely be critical, but over-looked, factor influences regeneration following reduction treatments. Using case study site southern Sierra Nevada Mountains California, whether rate recovery changes, depends strongly on plant accessible storage capacity within rooting zone extent which root structures neighboring trees interact share water. We find can yield remaining first few years treatment. However also when soils shallow roots systems overlap, counter-intuitive related occur due stress. Results highlight importance accounting site-specific variation, soil capacity, assessing how may with drought vulnerability, ultimately downslope streamflow.

Language: Английский

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