Environmental and biological interactions on productivity of silvopastoral system with Pinus contorta Doug. ex. Loud.
Environmental and biological interactions on productivity of silvopastoral system with Pinus contorta Doug. ex. Loud.wca2014-1170 Alvaro Sotomayor 1,* 1Sede Biobío, INSTITUTO FORESTAL, Concepcion, Chile
In a study conducted in the Aysen Region, located in the extreme south of Chile, it was evaluated the effect of Pinus contorta plantation, managed under two designed silvopastoral systems, in altering climatic parameters under its influence, such as wind speed, wind chill, relative humidity, ambient temperature and precipitation that reach the ground, and its effect on livestock and prairie production. The silvopastoral treatments evaluated were a) strips of four lines of trees, separated between 21 meters each other, and b) traditional silvopastoral system with trees spaced in the land, both with 400 trees ha-1, compared with c) animal production system without trees, as a control treatment. The results obtained shows that the trees managed under silvopastoral systems modified some ambient climatic parameters. The main parameter that was modified by the effect of the trees was average wind speed. The trees reduced the average wind speed in relation to the control treatment, by 200%. In relation to the wind chill, higher values were recorded between 22 to 26%, for the forest strip and traditional silvopastoral systems respectively, compared to livestock treatment. In average air temperature there was no difference and, relative humidity values were 0.2 to 0.6% higher in the silvopastoral treatments than the control. When analyzing the factors that influence pasture and livestock production, when tree density and arrangement were modified for silvopastoral purposes, positive correlations were obtained between canopy cover and wind speed of r2=0.95; between canopy cover and productivity of prairie the correlationship was r2=0.88 and r2=0.69 for traditional silvopastoral and strips treatment respectively; for animal productivity and wind velocity, it was obtained a r2=0.86. On linear models of more than one variable, also the forest crown coverage, associated with wind, was the variable most incident, which impacts positively the pasture productivity and consequently in animal production.