Examining the Potential of Forest Residue-Based Amendments for Post-Wildfire Rehabilitation in Colorado, USA

Charles C Rhoades,Eugene F Kelly,Derek N Pierson,Kerri L Minatre,Timothy S Fegel,M Francesca Cotrufo

doi:10.1155/2017/4758316

Charles C Rhoades, Eugene F Kelly + Show 4 more

Open Access

https://doi.org/10.1155/2017/4758316

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Abstract

Wildfire is a natural disturbance, though elemental losses and changes that occur during combustion and post-fire erosion can have long-term impacts on soil properties, ecosystem productivity, and watershed condition. Here we evaluate the potential of forest residue-based materials to rehabilitate burned soils. We compare soil nutrient and water availability, and plant recovery after application of 37 t ha−1 of wood mulch, 20 t ha−1 of biochar, and the combination of the two amendments with untreated, burned soils. We also conducted a greenhouse trial to examine how biochar influenced soil nutrient and water content under two wetting regimes. The effects of wood mulch on plant-available soil N and water content were significant and seasonally consistent during the three-year field study. Biochar applied alone had few effects under field conditions, but significantly increased soil pH, Ca, P, and water in the greenhouse. The mulched biochar treatment had the greatest effects on soil N and water availability and increased cover of the most abundant native plant. We found that rehabilitation treatments consisting of forest residue-based products have potential to enhance soil N and water dynamics and plant recovery following severe wildfire and may be justified where erosion risk or water supply protection are crucial.

Highlights

High-severity wildfires can cause significant, lasting impacts on forest soils and watersheds [1,2,3,4]
The frequency and extent of high-severity wildfires are projected to increase with a warming and drying climate in North American forests [12, 13] and land managers charged with maintaining forest productivity and desired watershed conditions will require effective tools for rehabilitating soils altered by severe wildfire
We evaluated the effect of rehabilitation treatments on plant, mineral soil, litter, and rock cover in August 2016 with a gridded point-intercept method in 1 m2 sample quadrats

Summary

Introduction

High-severity wildfires can cause significant, lasting impacts on forest soils and watersheds [1,2,3,4]. The immediate losses of organic matter and nutrients during wildfires reduce ecosystem nutrient and carbon stocks [5, 7, 8] which may require years to decades to replenish. Decreased post-fire plant cover and nutrient demand leads to increased leaching of soluble nutrients, notably nitrogen (N), from watersheds with extensive, high-severity wildfire [3, 9]. Soil nutrient losses and physical changes that influence plant-water availability can impede post-fire revegetation [10, 11]. The frequency and extent of high-severity wildfires are projected to increase with a warming and drying climate in North American forests [12, 13] and land managers charged with maintaining forest productivity and desired watershed conditions will require effective tools for rehabilitating soils altered by severe wildfire

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