Stone pine (Pinus pinea L.): an interesting species for agroforestry in Chile

Pinus pinea is native to the Mediterranean basin, being an interesting species due to its high-value edible pine nuts (prices between €20 and €45 kg−1), its ability to adapt to differing environmental conditions and its relative fast growth in Chile. The species was introduced to Chile more than one century ago by European migrants, who used it for dune stabilization, soil improvement and livestock shading. Agroforestry systems including stone pine and agricultural crops (forage oat and potatoes) and sheep grazing for mutton production were tested in two experimental plots located in El Carmen, Biobío region. The plots were evaluated during 5 years after planting. Crop yields were lower than the region average, reaching nearly 60% of national average yields of forage oat and 66–86% of potato. Forage production in these plots was not enough to sustain permanent grazing; however, sheep grazing in regulated periods contributes to mutton production. Grazing reduces weed and shrub growth, fire risk and the cost of periodic mechanical cleaning. Stone pine annual growth in height and diameter at collar height (ground level) were on average 50 and 2.5 cm, respectively, and was found to be a suitable species for agroforestry systems. Net present value was almost seven times higher in the agroforestry system than in pure stone pine plantations; therefore, this system can contribute to the local and national economy.