Portal de Periódicos da CAPES

Nocturnal water loss in mature subalpine Eucalyptus delegatensis tall open forests and adjacent E. pauciflora woodlands

2011; Wiley; Volume: 1; Issue: 3 Linguagem: Inglês

10.1002/ece3.44

2045-7758

Thomas N. Buckley, Tarryn L. Turnbull, Sebastian Pfautsch, Mark A. Adams,

Tree Root and Stability Studies

Abstract We measured sap flux ( S ) and environmental variables in four monospecific stands of alpine ash ( Eucalyptus delegatensis R. Baker, AA) and snowgum ( E. pauciflora Sieb. ex Spreng., SG) in Australia's Victorian Alps. Nocturnal S was 11.8 ± 0.8% of diel totals. We separated transpiration ( E ) and refilling components of S using a novel modeling approach based on refilling time constants. The nocturnal fraction of diel water loss ( f n ) averaged 8.6 ± 0.6% for AA and 9.8 ± 1.7% for SG; f n differed among sites but not species. Evaporative demand ( D ) was the strongest driver of nocturnal E ( E n ). The ratio E n / D ( G n ) was positively correlated to soil moisture in most cases, whereas correlations between wind speed and G n varied widely in sign and strength. Our results suggest (1) the large, mature trees at our subalpine sites have greater f n than the few Australian native tree species that have been studied at lower elevations, (2) AA and SG exhibit similar f n despite very different size and life history, and (3) f n may differ substantially among sites, so future work should be replicated across differing sites. Our novel approach to quantifying f n can be applied to S measurements obtained by any method.