Water storage dynamics in the main stem of subtropical tree species differing in wood density, growth rate and life history traits

LAUREANO OLIVA CARRASCO, SANDRA J. BUCCI, DÉBORA DI FRANCESCANTONIO, OSCAR A. LEZCANO, PAULA I. CAMPANELLO, FABIÁN G. SCHOLZ, SABRINA RODRÍGUEZ, N. MADANES, PIEDAD M. CRISTIANO, GUANG-YOU HAO, N. MICHELE HOLBROOK, AND GUILLERMO GOLDSTEIN

TREE PHYSIOLOGY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2014 vol. 31 p. 1 - 12

0829-318X

Wood biophysical properties and the dynamics of water storage discharge and refilling were studied in the trunk of canopytree species with diverse life history and functional traits in subtropical forests of northeast Argentina. Multiple techniquesassessing capacitance and storage capacity were used simultaneously to improve our understanding of the functional significanceof internal water sources in trunks of large trees. Sapwood capacitances of 10 tree species were characterized usingpressure?volume relationships of sapwood samples obtained from the trunk. Frequency domain reflectometry was used tocontinuously monitor the volumetric water content in the main stems. Simultaneous sap flow measurements on branches andat the base of the tree trunk, as well as diurnal variations in trunk contraction and expansion, were used as additional measuresof stem water storage use and refilling dynamics. All evidence indicates that tree trunk internal water storage contributesfrom 6 to 28% of the daily water budget of large trees depending on the species. The contribution of stored water in stemsof trees to total daily transpiration was greater for deciduous species, which exhibited higher capacitance and lower sapwooddensity. A linear relationship across species was observed between wood density and growth rates with the higher wooddensity species (mostly evergreen) associated with lower growth rates and the lower wood density species (mostly deciduous)associated with higher growth rates. The large sapwood capacitance in deciduous species may help to avoid catastrophicembolism in xylem conduits. This may be a low-cost adaptation to avoid water deficits during peak water use at midday andunder temporary drought periods and will contribute to higher growth rates in deciduous tree species compared with evergreenones. Large capacitance appears to have a central role in the rapid growth patterns of deciduous species facilitatingrapid canopy access as these species are less shade tolerant than evergreen species.