A model of soil water dynamics (SWATRE) and of the soil-plant-atmosphere continuum (SPAC), including the plant water-retention component, were applied independently to describe the seasonal and diurnal water balance of a forest in Italy. The stand under consideration was a 26-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation with a density of 2044 trees ha−1 and average height of 14.2 m, located in the Apennines in Central Italy, 900 m a.s.l, in a mediterranean climate. Soil water potential was measured with tensiometers and psychrometers 2 or 3 times per week during the summer of 1985. The xylem water potential and leaf stomatal conductance were measured on 4 days in the period June–September 1985, at about 2–3 h intervals from sunrise to sunset. Global and net solar radiation, air temperature and air relative humidity above the canopy were measured. Soil water potentials simulated by the SWATRE model agreed well with the field measurements. The diurnal pattern of bulk stomatal resistance and xylem water potential simulated by the SPAC model also agreed with measurements. The results show that Douglas-fir is surprisingly well adapted to the drought conditions that occurred in Tuscany during the dry year 1985, and even with dry soil, shallow rooting depth and high evaporative demand, trees did not show evident water stress.
Measured and simulated water relations in a Douglas-fir forest during the development of drought (Apennines, Central Italy).
BORGHETTI, Marco;
1988-01-01
Abstract
A model of soil water dynamics (SWATRE) and of the soil-plant-atmosphere continuum (SPAC), including the plant water-retention component, were applied independently to describe the seasonal and diurnal water balance of a forest in Italy. The stand under consideration was a 26-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation with a density of 2044 trees ha−1 and average height of 14.2 m, located in the Apennines in Central Italy, 900 m a.s.l, in a mediterranean climate. Soil water potential was measured with tensiometers and psychrometers 2 or 3 times per week during the summer of 1985. The xylem water potential and leaf stomatal conductance were measured on 4 days in the period June–September 1985, at about 2–3 h intervals from sunrise to sunset. Global and net solar radiation, air temperature and air relative humidity above the canopy were measured. Soil water potentials simulated by the SWATRE model agreed well with the field measurements. The diurnal pattern of bulk stomatal resistance and xylem water potential simulated by the SPAC model also agreed with measurements. The results show that Douglas-fir is surprisingly well adapted to the drought conditions that occurred in Tuscany during the dry year 1985, and even with dry soil, shallow rooting depth and high evaporative demand, trees did not show evident water stress.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
