The effect of forest harvesting in the first stages of lenga leaf litter decomposition in Tierra del Fuego, Argentina

MANSILLA, R; PANCOTTO, V; MORETTO, A; VRSALOVIC, J; LENCINAS, MV

Bariloche, Argentina

Congreso; VI Southern Connection Congress; 2010

Nothofagus pumilio forests of Tierra del Fuego are mainly managed by shelter-wood cut, and during the last time the intensity of forest harvesting was increasing. Our objective is to evaluate Nothofagus pumilio (lenga) litter decomposition in forests of Tierra del Fuego, managed by shelter-wood harvesting considering the main associated practices and recovery with time. We focus on three associated practices of forest harvesting 1) shelter-wood cut area, 2) stockpiled area, and 3) undisturbed forest (control), through the whole cycle management: at 1, 5-10, and 50 years after the harvesting. We evaluated decomposition of organic matter using litter bag method. At 3 month of decomposition, mass loss was higher (F=11.2 P<0.05) in areas with associated practices (shelter-wood cut and stockpiled areas) (17%) comparing with undisturbed forest (14.5%). The time since harvesting did not affect mass loss, however phosphorous and potassium release was higher (F=8.8 and F=11.0 respectively, P<0.05) for recent management (1 and 5 years) than for the older management (50 years). These preliminary results suggest that decomposition process is affected by forest harvesting and the recovery to preliminary conditions take more than 50 years.