Soil biogeochemical response to fire and the functional role of charcoal in temperate forests of the Olympic Peninsula, Washington

Beaver Plot 2 - 1 (2)
Beaver Fire, Olympic National Park, WA

Wildfires in the US are often maligned for the impairment of air and water quality, but also represent a natural and necessary process of renewal in fire adapted forest ecosystems. The natural function of fire in forest ecosystems is complex and many aspects are poorly understood. The purpose of this study is to quantify the impacts of wildfire on forest carbon and nutrient cycling and the legacy of charcoal in a mixed-severity fire ecosystem of the Olympic Peninsula in western Washington, USA. This research investigates an overlooked legacy of fire: charcoal, which is a ubiquitous byproduct of wildfires and prescribed fires that can alter carbon cycling, nutrient cycling, and nutrient availability. Research findings from this study will provide a thorough understanding of below-ground biogeochemical effects of fire where climate change may induce greater occurrence and severity of fires, which threaten immediate air and water quality conditions.

PI: Thomas H. DeLuca, University of Washington
Co-PI: Melissa RA Pingree, University of Washington


Biochar as a soil amendment to improve nutrient use efficiency in San Juan County

Morning Star Farm, Orcas Island, WA

San Juan County, a series of islands off the Washington coast, offers an ideal region for piloting a sustainable biochar amendment project. The area has urgent forest health treatment needs due to the fire risk across its isolated dry-forest ecosystem. The region’s soils are predominately variations of sandy loam glacial till, a soil with naturally high leaching capacity, offering optimal conditions to test biochar’s nutrient retention potential.

Starting summer 2015, researchers will establish replicated field plots on ten organic farms across Orcas (6 farms), San Juan (1 farm), and Waldron (3 farms) Islands in San Juan County, WA. The field study will investigate the impact of: 1) on-farm produced biochar on soil physical, chemical and biological properties; and 2) varying biochar application rates on plant and soil productivity.

PI: Thomas H. DeLuca, University of Washington
Co-PI: Si Gao, University of Washington


Metal deposition along an urban-to-wildland gradient in the Puget Sound Region

Hall of Mosses, Olympic National Park, WA

Despite their importance, and the iconic nature of PNW moss-covered forests, remarkably little is known about how  arboreal communities impact the biogeochemistry and functional biology of PNW forest ecosystems, particularly with respect to such issues as resilience to anthropogenic change. Creating a clear understanding of how our ever increasing transportation sector is influencing ecosystem functions within temperate forests will lead to improved policy and management decisions that otherwise would have ignored canopy epiphytes.

A combination of observational and manipulative studies will be conducted to determine the extent and severity of metal and N deposition rates from the urban center of Seattle to pristine wilderness ecosystems and then evaluate the influence of these pollutants on forest floor and canopy bryophytes and their role in ecosystem function. The results obtained from these studies will not only extend knowledge of pollution dynamics in the greater Seattle region, but also provide a conceptual link between transportation sector expansion and forest health.

PI: Thomas H. DeLuca, University of Washington
Co-PI: Amanda Bidwell, University of Washington


Soil biochemical response to salvage logging treatments in Northern California

King Fire, El Dorado County, California
El Dorado National Forest, CA

While it is well known that severe wildfires have the potential to consume surface organic horizons and alter soil nutrient cycles, less is known regarding the subsequent effects of salvage logging on soil process and function. The purpose of this study is to evaluate the influence of post fire salvage logging on soil biochemical properties and processes. Specifically we intend to address the following three objectives: (1) determine how post fire salvage logging influences soil nitrogen and phosphorus status  ; (2) evaluate the influence of salvage logging on surface soil carbon storage and mixing of charcoal into the surface mineral soil; (3) Assess the effect of salvage logging on soil biotic properties including microbial biomass and decomposition rates.

PI: Thomas H. DeLuca, University of Washington
Co-PI: Ernesto Alvarado, University of Washington; Morris Johnson, USFS Fire Laboratory Seattle; Melissa Pingree, University of Washington


Recalling the Past: cultural heritage, landscapes and identity processes in northern Fennoscandia

Renhagamyren, Northern Sweden

Using a combination of historical data and archaeological and ecological landscape-orientated methods we are testing the notion that organized agrarian society was established far earlier in northern Sweden that previously thought.  Archaeological and ecological field surveys at forty-eight sites in north eastern Sweden are being used for detailed examination. Results from pollen analyses at coastal sites show that shifting cultivation was established from 550 BC in Västerbotten and from AD 200 in Norrbotten and that permanent cultivation was established from AD 1300 onwards.  These results suggest much more complex land use strategies than previously acknowledged, corroborating the existence of a shifting form of small scale cultivation restricted both temporally and spatially and thus differing from slash-and-burn cultivation and permanent fields. The general idea that cereal cultivation was first established in this region in connection with migrating farmers pushing back a northern frontier is hereby questioned. Instead, shifting cultivation seems to have occurred within the framework of hunter–gatherer and pastoralist subsistence as a result of combined internal and external processes.

PI: Thomas H. DeLuca, University of Washington


Biological legacies and ecosystem function: carbon, nitrogen, and phosphorus dynamics across gradients of disturbance and community composition at Mount St. Helens

Pumice Plain, Mount St. Helens National Monument, WA

The study of succession often uncovers unexpected lessons about the complexity of life and how biological communities develop over time. Soil development is often an essential factor in succession, especially in the case of primary succession, where soil is initially of poor quality and devoid of essential nutrients. The 1980 eruption of Mount St. Helens was one of the biggest and most complex disturbance events easily accessible for intensive study not only in the PNW but across the world. To date, there has been a significant effort to describe plant successional patterns at Mount St. Helens (Crisafulli et al. 2005). However, there has been no holistic attempt to characterize the rate and source of soil development along a gradient of disturbance intensities throughout Mount St. Helens National Monument. This research intends to address the following: (1)how do nutrient dynamics drive plant succession across a disturbance gradient; (2) how do plant succession legacies impact soil development and nutrient pools; and (3) what are the relative roles of above versus belowground plant dynamics on soil development over the course of succession.

PI: Thomas H. DeLuca, University of Washington

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