Variability of hydraulic conductivity and water repellency of soils with fire severity in pine forests and reforested areas under Mediterranean conditions

Abstract

The effects of fire on soil hydraulic conductivity (K) and soil water repellency (SWR) have been mainly studied by field experiments in forest areas burned by wildfires with a given severity, while the variability of K and SWR with the fire severities has been less investigated. To fill this gap, the changes in the K and SWR with fire severity and soil depth (1 and 5 cm below the ground surface) have been evaluated in two forest ecosystems (natural stand of pine and reforested areas) of Central Eastern Spain. A significant influence of the fire severity on the infiltration rates was found, and this influence was different between the natural stand of pine and the reforested areas. Compared to the unburned soils, the highest reduction of the K (80% to 90%) and SWR levels were found for the fires with low and intermediate severities at the soil surface. At the lower soil depth, the reduction of K and the SWR level due to fire were proportional to its severity. Moreover, the K of the soil surface layer was often higher compared to the water infiltration in the deeper layer. In the reforested areas, also low fire severities can noticeably reduce the surface K, despite the limited SWR, while the natural forests are less exposed to hydrophobicity in their surface soil layer. This study indicates the need to reduce the risk of flooding and erosion linked to a reduction in water infiltration and increase of soil repellency.

Effects of prescribed fire on the post‐fire hydrological processes in agro‐forest ecosystems: A systematic review and a meta‐analysis

“…Prescribed fire is carried out under controlled climatic and morphological conditions that avoid the triggering of high‐severity fires. However, the soil burn severity, although not burning the tree canopies, may also be moderate and high, and this may noticeably alter the hydrological properties of burned soils (Lucas‐Borja, De Las Heras, Moya Navarro, González‐Romero, et al, 2022; Lucas‐Borja, Fernández, Plaza‐Alvarez, & Zema, 2022). According to this meta‐analysis, water infiltration underwent significant variations among classes of soil burn severity, and noticeably decreased at moderate severities, while the effects of low and low‐to‐moderate severities were lower or absent in the short‐term.…”

Efeito da reabilitação de áreas de mineração de bauxita na infiltração e na repelência do solo à água

“…Após incêndios florestais ocorre um aumento significativo da repelência de água no solo (KEESSTRA, et al, 2017). O calor liberado pelo fogo migra da superfície para as camadas mais profundas, sendo que os efeitos do fogo nas propriedades do solo diminuem com a profundidade (LUCAS-BORJA et al, 2022). Durante a queima, as substâncias hidrofóbicas cimentam-se na camada subsuperficial do solo (Hester et al, 1997).…”

Soil recovery in cacao and coffee agroforestry systems : Litter, roots, carbon, and water

“…Previous studies on soil water repellency (SWR) have predominantly focused on a specific condition, such as post forest fire (Caltabellotta et al 2022;DeBano 1991;Lucas-Borja et al 2022;Stoof et al 2011), sandy soils (Doerr et al 2005;Siteur et al 2016;Wong et al 2022;Wong et al 2021), under certain tree species known to contain hydrophobic compounds like pine and eucalyptus (Leighton-Boyce et al 2005;Lozano et al 2013;Mataix-Solera et al 2007;Neris et al 2013) or volcanic ash-derived soils (Jordán et al 2011;Jordán et al 2009;Kawamoto et al 2007;). However, SWR under a cacao-based system, with the non-specific conditions mentioned before, has not been well characterized until recently reported by Farrick and Gittens (2022) in Trinidad and Tobago.…”