Tree water use and rainfall partitioning in a mature poplar-pasture system

• DOI: 10.1093/treephys/20.2.97
• Publication Date: 2012-04-06T16:37:36Z
• Authors: A. Guevara-Escobar; W. R. N. Edwards; R. H. Morton; P. D. Kemp; A. D. Mackay
• Keywords: Interception; Understory; Tree canopy

Traditionally, poplars (Populus) have been planted to control erosion on New Zealand's hill-slopes, because of their capacity dry out and bind together the soil, by reducing effective rainfall increasing evapotranspiration soil strength. However, effect widely spaced partitioning water has not reported. This study determined for 18 mid-spring days in a mature P. deltoides (Bart. exMarsh, Clone I78)–pasture association (37 stems per hectare, unevenly at 16.4 ± 0.4 m) compared it with traditional open pasture system grazed areas hill environment. Tree transpiration was measured heat pulse technique. A time-driven mathematical model used set zero offset, adjust anomalous values describe simultaneous sap velocity time courses trees. The showed that daylight flow velocities can be represented nonlinear Beta function (R2 > 0.98), differences parameters representing initiation, duration conformation tested statistically discern tree during day. Evapotranspiration greater poplar–pasture than (2.7–3.0 versus 2.2 mm day−1). canopy alone contributed 0.92 day−1 as 1.37 interception, whereas understory only 0.4–0.6 day−1. Despite higher use association, 0–300 stratum than, or similar to, pasture. shading decreased accumulation under