INVESTIGADORES
FERNANDEZ Maria elena
congresos y reuniones científicas
Título:
Increased transpiration and soil water depletion by exotic ponderosa pine plantations partially offset by decreased interception in northwestern Patagonia, Argentina.
Autor/es:
LICATA, J.; GYENGE, J.; MARIA ELENA FERNANDEZ; T.G. PYPKER; SCHLICHTER, T.; BOND, B.
Lugar:
San José- California
Reunión:
Congreso; ESA/SER Joint Meeting; 2007
Resumen:
Exotic ponderosa pine
plantations are being planted in the natural distribution area of cordilleran
cypress (Austrocedrus chilensis(D.Don) Pic. Ser. et Bizzarri) in Argentinean
Andean Patagonia. The productivity of exotic
plantations is much greater than native forests (Schlichter and Laclau, 1998),
which suggests greater utilization of water resources. We hypothesized that: 1-
ponderosa pine plantations have higher total annual transpiration than native
cordilleran cypress stands, due to higher transpiration rates and/or longer
growing season; 2- they extract water from deeper soil layers and deplete water
to lower levels of soil moisture; and 3- rainfall interception losses are
similar between species but vary with tree density. Using continuous
measurements of sap flow, soil water content and below- and above-canopy
rainfall precipitation, we examined the water budget components of four forest stands:
a high density ponderosa pine timber plantation (HDPP), a low density
silvopastoril ponderosa pine plantation (Silvo), a low and a high density
cordilleran cypress stands (LDCip and HDCip respectively). Measurements
were carried out during two years with contrasting amounts of precipitation.
HDPP had the highest use of water at the stand level. Water depletion was
observed simultaneously at all depths for all the sites, even in the wet year.
Differences between the soil water depletion and sap flow suggests a higher use
of water below 1.8m by the HDPP stand than the rest of the stands. Rainfall
interception losses were greater in the native stands, and partially
compensated the increased evapotranspiration of the exotic plantations.