Woody productivity of Prosopis flexuosa D.C. woodlands in the central Monte: influence of the population structure and tree growth habit

ALVAREZ, J.A.; VILLAGRA, P.E.; VILLALBA, R.; CONY, M.A.; ALBERTO, M.

JOURNAL OF ARID ENVIRONMENTS

ACADEMIC PRESS LTD-ELSEVIER SCIENCE LTD

Año: 2011 vol. 75 p. 7 - 13

0140-1963

The equilibrium between forest production and protection is hard to achieve in arid zones due to the low potential for wood production. Prosopis flexuosa woodlands are the major woody formations in the Monte desert and show a degraded state due to intense use. The main factors of degradation in the study area are overgrazing and fuelwood extraction. We developed allometric models to estimate the P. flexuosa aerial biomass, compared the annual growth rates of one- and multi-stem individuals through dendrochronological methods, and estimated the productivity of four structurally different woodlands in the central Monte. Total dry weight was best estimated by power equations. Annual increments in basal area and dry weights were initially larger in multi- than one-stem individuals. However, whereas multi-stem individuals rapidly decreased their growth rates after 60 years, one-stem trees maintain steady growth rates during the first 100 years. Depending on woodland density and tree size, the total woodland biomass varied between 4 000 and 15 000 kg ha-1. Woody productivity was similar in the four studied woodlands (121.6-173.7 kg ha-1 year-1). Our results reveal the importance of the tree growth habit in productivity, and suggest that the regulated extraction of firewood and posts from multi-stem old individuals could optimize the woody productivity and contribute to sustainable use and conservation of these woodlands.