Humus forms in Mediterranean scrublands with aleppo pine

Commonly reported effects of pine on topsoil include acidification, a decre ase in biological activity, and an accumulation of surface organic matter. Such effects have not been documented for Mediterranean woodland and scrubl and areas. This research evaluated humus profiles beneath pine and adjacent vegetation on the basis of previous knowledge on soil animal communities a nd vegetation. Two Mediterranean sites with aleppo pine (Pinus halepensis P , Mill.) and scrubland vegetation were compared, one in Spain (Navarre), th e other in Italy (Sicily), Humus profiles were sampled under main vegetatio n types, comprising aleppo pine, rosemary (Rosmarinus officinalis L,), and bare ground in both sites, along transects with increasing pine influence. Quantitative morphological methods were used to analyze and compare humus p rofiles, and data were analyzed using correspondence analysis. In both site s the influence of aleppo pine on humus forms was well-defined but minor, i ncreasing the appearance of an Oe horizon characterized by intense activity of litter-dwelling Fauna and fungi, Under all vegetation types, and in bot h sites, the organomineral A horizon was of the mull type, although the com position of the soil-building fauna varied between Navarre and Sicily, Ther e was more heterogeneity among vegetation types in Navarre, where aleppo pi ne was planted on derelict land, than in Sicily where aleppo pine was a com ponent of natural vegetation (maquis), A decreasing influence of pine was p erceptible in the inner edge of the pine plantation in Navarre, or under th e crown of individual trees in Sicily.