Structural and functional changes in Nothofagus pumilio forests along an altitudinal gradient in Tierra del Fuego, Argentina

Structural (density, height, basal area, above-ground tree biomass, leaf ar ea index) and functional (leaf phenology, growth rate, fine litter fall, le af decomposition) traits were quantified in four mature forests of Nothofag us pumilio (lenga) along an altitudinal sequence in Tierra del Fuego, Argen tina. Three erect forest stands at 220, 440 and 540 m and a krummholz stand at 640 m a.s.l. were selected. Along the altitudinal sequence, stem densit y increased while DBH, height, biomass, leaf-size and growth period, mean g rowth rate and decay rate decreased. Dead steins increased and basal area a nd fine-litter fall decreased with an increase in elevation among erect for ests, but these trends inverted at krummholz. We suggest that krummholz is not only a morphological response to the adverse climate but is also a life form with functional advantages.