Compactación en suelos forestales: ¿mejor pezuñas o neumáticos?

Soil compaction arising from forest resources exploitation is currently subject of recurrent debate, particularly in Spain, where there is an ongoing increase of logging mechanization level. The present study aims at analysing and comparing the soil compaction status resulting either from longterm machinery traffic during logging operations (ground based full tree logging with hand-felling, winching and skidder yarding) or from cattle traffic (extensively managed cows, mainly) within a scots pine forest located in the Spanish central mountains, over sandy loam soils, where both uses have been carried out for more than five decades. Soil penetration resistance was assessed from 0 to 50 cm depth in 180 points randomly selected within four 100x100 blocks throughout the forest. The results showed that: 1) after the long period of use,there were no significant differences between the average penetration resistance profiles (0-50 cm) of hightraffic points of machinery and of cattle; 2) high and low traffic areas showed significant differences increasing till 16.8 cm depth where the maximum absolute disturbance was reached (406.3 kPa); 3) from 16,8 cm depth on, differences decreased to become no longer significant at 36,8 cm depth. The present case shows that predictions concerning soil compaction effects of a forest use require taking into account not only the type of compacting agent, but also charges features and perturbations regimen. La compactación edáfica derivada de diferentes aprovechamientos forestales es actualmente tema de debate, particularmente en el contexto español en el que existe un nivel creciente de mecanización en la extracción de madera. Este trabajo tiene como objetivo comparar los niveles de compactación resultantestras cinco décadas de tránsito de maquinaria durante los aprovechamientos mecanizados de madera (apeo con motosierra y saca con skidder de neumáticos), con el derivado del tránsito de ganado pastante (en el último siglo mayoritariamente vacuno en extensivo), en una masa de pino silvestre de la Sierra deGuadarrama sobre suelos franco-arenosos. Para ello se cuantifica la resistencia a penetración del suelo entre 0 y 50 cm de profundidad en 180 puntos repartidos aleatoriamente en el monte. Los resultados obtenidos muestran que: 1) no existen diferencias significativas en los primeros 50 cm entre los perfiles medios de resistencia a penetración del suelo generados por maquinaria y ganado en las zonas de alto tránsito; 2)dichas zonas