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The canopy leaf area (CLA) of woody plants is a key trait influencing canopy transpiration, simultaneously controlling stomatal water efflux and photosynthetic carbon assimilation. However, precise quantification of diurnal whole canopy carbon-water fluxes remains difficult due to limitations in nondestructive CLA measurement. Here, we used the leaf area index (LAI) method, the basal diameter derivation (BDD) method, the oven-drying and weighing method, and allometric relationships to estimate the CLA of Caragana korshinskii across different ages and quantify the daily photosynthetic carbon assimilation and transpiration. We found that the LAI method underestimated CLA in younger C. korshinskii shrubs. In contrast, the BDD method overestimated CLA in older individuals, highlighting the limitations of both methods in accurately estimating CLA across different age groups. The multitrait allometric relationships developed by key morphological traits could accurately estimate the CLA of C. korshinskii shrubs compared to other methods. Quantitative analysis revealed that whole-canopy photosynthetic carbon assimilation and transpiration of C. korshinskii were significantly higher with groundwater than without it, reflecting an adaptive drought strategy that improves water use efficiency by maximizing carbon gain and minimizing water loss. Our results highlighted that the multitrait allometric relationships could more accurately estimate the CLA of C. korshinskii, providing new methodological perspectives for quantifying shrub canopy dynamics and carbon-water fluxes in arid desert ecosystems.
Huo et al. (Sat,) studied this question.