Grassland productivity and consumption under different tree cover in the Aysen region, Patagonia, Chile

摘要

Herbaceous vegetation under different tree cover has been studied in the Aysen region in the northern Patagonia of Chile, in order to test the feasibility of silvopastoral agroforestry in this region. Within a moderately altered deciduous forest of Lenga (Nothofagus pumilio), grassland productivity and consumption by cattle was estimated in 400 m2 plots with different degrees of tree cover, from 0-80%. In each plot, under and between tree crown patches were compared. No differences were observed in grassland production between full-open grassland and plots with different tree cover. However, with increasing tree cover, herbaceous production and consumption decreased under tree crowns, but this decrease was compensated for by an increase in productivity between tree crowns. This resulted in similar average pasture production in open grassland and with trees, across the range of cover. Taking into account the trade off mentioned above, it appears that maintaining Lenga forest on pasture land, with tree cover ranging from 50 to 75%, yields optimal productivity for cattle in this region, and allows production of valuable timber as well. Thus, silvopastoral agroforestry is an attractive option for this region.