TITLE	Vertical profiles of CO2 concentration and d13C values in a subalpine forest of Taiwan
AUTHOR	Wen-Yuan Kao Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China Yu-Shiun Chiu Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China Wan-Hwa Chen Institute of Botany, Academia Sinica, Taipei, Taiwan, Republic of China
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ABSTRACT	We investigated the vertical gradients in CO2 concentration and stable carbon isotope ratio (d13Cco2) of the canopy air within a coniferous-hardwood, Chamaecyparis and Rhododendron dominated, subalpine forest in Taiwan. The stable carbon isotope ratio of vascular plants and a epiphytic bryophyte species (Bazzania fauriana) (d13Cleaf) from different heights within the forest were also analyzed. Results revealed that CO2 and d13Cco2 gradients did exist within the forest, with higher CO2 concentrations and more negative d13Cco2 values in air sampled from the lower canopy. The average vertical gradients in CO2 and d13Cco2 value of the CO2 of the 12 sampling dates were 28.5 ± 6.1 ppm and 1.3 ± 0.3‰, respectively. Seasonal patterns of the relationship between 1/[CO2] and the corresponding d13C were pronounced, with steady decreases in the slopes and increases in the intercepts found from January to August. A decreasing d13Cleaf with decreasing height was also measured in a bryophyte (ranging from -27.4 to -29.2‰), canopy and understory leaves (ranging from -28.6 to -33.5‰). It was estimated that photosynthetic physiology affected by microclimates within the forest contributed approximately 2.8‰ of variation of the vertical gradient of vascular plant d13C values.
KEYWORD	Bryophyte; CO2 ; Subalpine forest; Stable carbon isotope ratio;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 41 Number 3 July 2000, page 213-218, 6 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China