Ground‐level changes after wildfire and ploughing in eucalyptus and pine forests, Portugal: implications for soil microtopographical development and soil longevity

Abstract

Soil level changes over four years at 50 sites in three types of post-fire eucalyptus and pine forest management practices (natural pine seedling regeneration; eucalyptus regrowth from coppiced stumps; and deep-(rip-) ploughed areas planted with eucalyptus seedlings) in the Á gueda Basin, Portugal are reported. Average ground lowering at regrowth sites was high during the first year after fire (up to an estimated 18 mm), declining sharply by the third year with vegetation growth and litter cover development. In the first year after rip-ploughing, there was greater surface lowering (up to 27 mm recorded), with recovery within three-four years. This sharp post-ploughing reduction in soil loss is attributed to stone lag development through erosion of fines. Soil erosion resulting from a wildfire-rip-ploughing cycle is estimated to be up to 174 t ha À1

Reduction of nutrient losses with eroded sediments by post-fire soil stabilisation techniques

“…By contrast, other authors consider that soil quality might well be seriously affected through preferential loss of fines and organic matter, both of which contain more nutrients than does the remainder of the soil (Thomas et al 1999;Shakesby et al 2002). Moreover, the fate of eroded C (e.g.…”

Runoff and inter-rill erosion in a Maritime Pine and a Eucalypt plantation following wildfire and terracing in north-central Portugal

“…For example, variations in logging activities of Eucalypt plantations in northeastern Spain resulted in erosion rates ranging from less than 1 to more than 40 Mg ha -1 y -1 (Fernandéz et al, 2004). In northcentral Portugal, rip-ploughing in downslope direction led to greater soil losses than wildfire (Shakesby et al, 1994). Ripploughing in downslope direction is now forbidden in the study region but the construction of terraces for reforestation with Eucalypt has become increasingly common, especially also in recently burnt areas (Fig.…”

Soil Erosion Under Different Land Use and Cover Types in a Marginal Area of Portugal

“…The gradual depletion of nutrients, which reduces soil fertility and creates a high level of soil degradation, are further reasons for abandoning agricultural plots in the changing cultivation process (Paniagua et al, 1999). Planting trees, according the CAP measures for afforestation of marginal fields, with deep ploughing and bare soil has resulted in very high erosion rates during both rainfall seasons, as observed in other agro-ecosystems in Mediterranean Europe (Shakesby et al, 2002;Ternan et al, 1997;Van-Camp et al, 2004). However, in large parts of marginal areas of the country farmland abandonment has enhanced plant colonisation, replacing historically highly erosive cereal fields with dense shrub and woodland communities.…”

“…This rising trend, although including some periods of lower burnt area, distinguishes Portugal from the other southern Member States with the highest burnt areas, particularly in the central and northern regions. It is commonly accepted that fire increases runoff and soil erosion (Benavides-Solorio & MacDonald, 2005;Cerdà & Doerr, 2005;Cerdà & Lasanta, 2005;Coelho et al, 2004;Ferreira et al, 2005Ferreira et al, , 2008Shakesby et al, 1993Shakesby et al, , 1996Shakesby et al, , 2002. Increased erosion after forest fire stems primarily from the destruction of vegetation and changes in the soil physical and hydrologic properties that reduce infiltration rates and increase availability of loose sediment (Ferreira et al, , 2008.…”