22 Soil Fertility After Fire and Clear-Cutting
Isabel Serrasolses and V. Ramon Vallejo
22.1 Introduction
Holm oak (Quercus ilex L.) forests have been disturbed for centuries by coppicing for firewood and charcoal production, grazing and wildfires. Though
at present many holm oak forests of southern Europe remain unexploited,
most holm oak forests in Catalonia (NE Spain) are managed for firewood
through selection thinning (Chaps. 3 and 5). Substantial amounts of slash are
left to decompose on site after each cutting cycle.
Slash management can have a considerable impact on forest productivity
(Fahey et al. 1991). Slash removal gives rise to a net nutrient loss whereas
laying slash down protects the soil from erosion and incorporates nutrients
into the soil through decomposition. Slash-burning produces a loss of C and
certain nutrients, especially Nand S, depending on the intensity of the fire
(Raison et al. 1985b; Gillon and Rapp 1989). In spite of this nutrient loss, the
post-fire soil is enriched by ashes, thereby increasing nutrient availability
(Woodmansee and Wallach 1981; Khanna et al. 1994). The question remains
though as to what extent the losses produced by volatilization and convection, and eventually by ash leaching or washout, are reversible and affect forest regrowth either in the short or long term.
Clear-cutting and slash-burning treatments were conducted in the holm
oak coppices of the Prades experimental area: (1) to analyze the short-term
forest response in the case of an intense wildfire; and (2) to assay the effects
of two techniques for the management of forest slash: slash-burning and
laying down the slash to decompose on the forest floor.
22.2 Experimental Design
The experiment was conducted on the SE-facing slope of Torners (Chap. 2),
at an altitude of 900 m a.s.l. Three 40 x 20-m plots were used, one of them
being kept undisturbed as a control (Serrasolsas 1994). The trees of the other
Ecological Studies, Vol. 137
Ferran RodS. et al. (eds) Ecology of Mediterranean
Evergreen Oak Forests
© Springer-Verlag, Berlin Heidelberg 1999
Isabel Serrasolses and V. Ramon Vallejo
22.1 Introduction
Holm oak (Quercus ilex L.) forests have been disturbed for centuries by coppicing for firewood and charcoal production, grazing and wildfires. Though
at present many holm oak forests of southern Europe remain unexploited,
most holm oak forests in Catalonia (NE Spain) are managed for firewood
through selection thinning (Chaps. 3 and 5). Substantial amounts of slash are
left to decompose on site after each cutting cycle.
Slash management can have a considerable impact on forest productivity
(Fahey et al. 1991). Slash removal gives rise to a net nutrient loss whereas
laying slash down protects the soil from erosion and incorporates nutrients
into the soil through decomposition. Slash-burning produces a loss of C and
certain nutrients, especially Nand S, depending on the intensity of the fire
(Raison et al. 1985b; Gillon and Rapp 1989). In spite of this nutrient loss, the
post-fire soil is enriched by ashes, thereby increasing nutrient availability
(Woodmansee and Wallach 1981; Khanna et al. 1994). The question remains
though as to what extent the losses produced by volatilization and convection, and eventually by ash leaching or washout, are reversible and affect forest regrowth either in the short or long term.
Clear-cutting and slash-burning treatments were conducted in the holm
oak coppices of the Prades experimental area: (1) to analyze the short-term
forest response in the case of an intense wildfire; and (2) to assay the effects
of two techniques for the management of forest slash: slash-burning and
laying down the slash to decompose on the forest floor.
22.2 Experimental Design
The experiment was conducted on the SE-facing slope of Torners (Chap. 2),
at an altitude of 900 m a.s.l. Three 40 x 20-m plots were used, one of them
being kept undisturbed as a control (Serrasolsas 1994). The trees of the other
Ecological Studies, Vol. 137
Ferran RodS. et al. (eds) Ecology of Mediterranean
Evergreen Oak Forests
© Springer-Verlag, Berlin Heidelberg 1999