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Canopy transpiration in a chronosequence of Central Siberian pine forests
Author(s) -
Zimmermann Reiner,
Schulze Ernst Detlef,
Wirth Christian,
Schulze ErnstEckart,
Mcdonald Kyle C.,
Vygodskaya Natascha N.,
Ziegler Waldemar
Publication year - 2000
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.2000.00289.x
Subject(s) - transpiration , canopy , xylem , leaf area index , environmental science , dry weight , vapour pressure deficit , chronosequence , flux (metallurgy) , canopy conductance , atmospheric sciences , horticulture , botany , zoology , hydrology (agriculture) , biology , soil water , chemistry , soil science , geology , photosynthesis , geotechnical engineering , organic chemistry
Summary Tree transpiration was measured in 28, 67, 204 and 383‐y‐old uniform stands and in a multicohort stand (140–430 y) of Pinus sylvestris ssp. sibirica Lebed. in Central Siberia during August 1995. In addition transpiration of three codominant trees was monitored for two years in a 130‐y‐old stand. All stands established after fire. Leaf area index ( LAI ) ranged between 0.6 (28‐y‐old stand) and 1.6 for stands older than 67‐y. Stand xylem area at 1.3 m height increased from 4 cm 2 m −2 (28‐y) to 11.5 cm 2 m −2 (67‐y) and decreased again to 7 cm 2 m −2 in old stands. Above‐ground living biomass increased from 1.5 kg dry weight m −2 (28‐y) to 14 kg dry weight m −2 (383‐y). Day‐to‐day variation of tree transpiration in summer was dependent on net radiation, vapour pressure deficit, and soil water stress. Tree‐to‐tree variation of xylem flux was small and increased with heterogeneity in canopy structure. Maximum rates of xylem flux density followed the course of net radiation from mid April when a constant level of maximum rates was reached until mid September when low temperatures and light strongly reduced flux density. Maximum sap flux density (60 g m −2 s −1 ) and canopy transpiration (1.5 mm d −1 ) were reached in the 67‐y stand. Average canopy transpiration of all age classes was 0.72 ± 0.3 mm d −1. Canopy transpiration ( E ) was not correlated with LAI but related to stand sapwood area SA ( E = − 0.02 + 1.15 SA R 2 ) which was determined by stand density and tree sapwood area.