title: Predicting the limits to tree height using statistical regressions of leaf traits.
abstract: Leaf morphology and physiological functioning demonstrate considerable plasticity within tree crowns, with various leaf traits often exhibiting pronounced vertical gradients in very tall trees. It has been proposed that the trajectory of these gradients, as determined by regression methods, could be used in conjunction with theoretical biophysical limits to estimate the maximum height to which trees can grow. Here, we examined this approach using published and new experimental data from tall conifer and angiosperm species. We showed that height predictions were sensitive to tree-to-tree variation in the shape of the regression and to the biophysical endpoints selected. We examined the suitability of proposed end-points and their theoretical validity. We also noted that site and environment influenced height predictions considerably. Use of leaf mass per unit area or leaf water potential coupled with vulnerability of twigs to cavitation poses a number of difficulties for predicting tree height. Photosynthetic rate and carbon isotope discrimination show more promise, but in the second case, the complex relationship between light, water availability, photosynthetic capacity and internal conductance to CO(2) must first be characterized.
authors: School of Plant Biology, University of Western Australia, 35 Stirling Highway, Crawley WA 6009 Australia.|Cooperative Research Centre for Plant-Based Management of Dryland Salinity, 35 Stirling Highway, Crawley WA 6009 Australia.|Department of Integrative Biology, University of California, Berkeley, CA 94720 USA.
authors: Stephen S O
authors: SSO
authors: Burgess
authors: Department of Integrative Biology, University of California, Berkeley, CA 94720 USA.
authors: Todd E
authors: TE
authors: Dawson
mesh_terms: D008027:Light; D018515:Plant Leaves / Q000033:anatomy & histology* / Q000502:physiology; D012044:Regression Analysis; D032487:Sequoia / Q000033:anatomy & histology* / Q000502:physiology; D064028:Tracheophyta / Q000033:anatomy & histology; D014197:Trees / Q000033:anatomy & histology* / Q000502:physiology; D014867:Water; D052584:Xylem / Q000502:physiology
chemical_list: D014867:Water