Postfire soil water repellency in piñon–juniper woodlands: Extent, severity, and thickness relative to ecological site characteristics and climate

Abstract

Wildfires can create or intensify water repellency in soil, limiting the soil's capacity to wet and retain water. The objective of this research was to quantify soil water repellency characteristics within burned piñon–juniper woodlands and relate this information to ecological site characteristics. We sampled soil water repellency across forty‐one 1,000 m2 study plots within three major wildfires that burned in piñon–juniper woodlands. Water repellency was found to be extensive—present at 37% of the total points sampled—and strongly related to piñon–juniper canopy cover. Models developed for predicting SWR extent and severity had R 2 adj values of 0.67 and 0.61, respectively; both models included piñon–juniper canopy cover and relative humidity the month before the fire as coefficient terms. These results are important as they suggest that postfire water repellency will increase in the coming years as infilling processes enhance piñon–juniper canopy cover. Furthermore, reductions in relative humidity brought about by a changing climate have the potential to link additively with infilling processes to increase the frequency and intensity of wildfires and produce stronger water repellency over a greater spatial extent. In working through these challenges, land managers can apply the predictive models developed in this study to prioritize fuel control and postfire restoration treatments.

Light Grazing Significantly Reduces Soil Water Storage in Alpine Grasslands on the Qinghai-Tibet Plateau

“…Furthermore, the litter did not consume any water. Therefore, an increase in the quantity of litter improved the soil's water permeability and retention capacity, and indirectly improved the soil's water-conservation function, as supported by the studies of Zvirzdin et al [19] and Wall and Heiskanen [20], respectively. Shallow groundwater is an important contributor to grassland moisture: the deeper the water table, the less compensation it provides for grassland moisture losses.…”

Anchor Chaining’s Influence on Soil Hydrology and Seeding Success in Burned Piñon-Juniper Woodlands

“…Despite this limitation in the study design, it can be assumed that areas with high cover of piñon and juniper trees may benefit most from reductions in soil−water repellency through anchor chaining because the canopy area is most susceptible to the development of soil−water repellency (Madsen et al, 2008(Madsen et al, , 2012a(Madsen et al, , 2012b(Madsen et al, , 2012cZvirzdin, 2012;Williams et al 2014). The need for effective postfire restoration treatments that address soil−water repellency issues will increase as piñon-juniper woodlands expand into historically dominant sagebrush/bunchgrass vegetation, increase cover in existing woodland communities, and promote large-scale wildfires.…”

“…Postfire anchor chaining may also improve seeding success by mitigating the effects of soil−water repellency as this condition is well documented in piñon-juniper woodlands (Jaramillo et al, 2000;Madsen et al, 2008;Madsen et al, 2012a;Roundy et al, 1978;Scholl, 1971;Zvirzdin, 2012). Although soil−water repellency is often present prior to fire, burning can increase its severity and spatial consistency (Doerr et al, 2000).…”

“…A plot radius of 2.0 m was chosen because most preburn canopies in the study area extended approximately this distance; as estimated from remaining tree branches and burned litter material at the soil surface. Research was focused on the canopy area because this is the area where the effects of soil repellency are expected to be greatest (Madsen et al, 2008(Madsen et al, , 2012a(Madsen et al, , 2012b(Madsen et al, , 2012cZvirzdin, 2012).…”

Seasonal Wetness, Soil Organic Carbon, and Fire Influence Soil Hydrological Properties and Water Repellency in a Sagebrush‐Steppe Ecosystem

“…Reduced infiltration capacity following fire has often been attributed to increased SWR (Dekker & Ritsema, ; Martin & Moody, ; Pierson et al, ). However, the substantial spatial variability in SWR at rangeland sites both before and after fire indicates that fire‐associated differences in infiltration are neither uniform nor persistent (Pierson et al, , ; Woods et al, ; Zvirzdin et al, ). Studies of postfire SWR in pine forests found SWR persisted from 1 to 6 years (Dyrness, ; MacDonald & Huffman, ).…”