Lechowicz, Martin , Kikuzawa, Kihachiro .
Scaling production from leaf to canopy.
THE assimilation of carbon by plant communities (gross primary production: GPP) is a central concern in plant ecology as well as for our understanding of global climate change. As an alternative to traditional methods involving destructive harvests or time-consuming measurements, we present a simple, general model for GPP as the product of lifetime carbon gain by a single leaf, daily leaf production rate and the length of the favorable period for photosynthesis. To test the model we estimated leaf lifetime carbon gain for 26 species using the concepts of mean labor time for leaves (the part of each day the leaf functions to full capacity), average potential photosynthetic capacity over the leaf lifetime, and functional leaf longevity (leaf longevity discounted for periods within a year wholly unfavorable for photosynthesis). By building on these novel concepts we were able to create an effective scaling of productivity processes from leaf up to canopy level. We found that the lifetime carbon gain of leaves was rather constant across species. Moreover, when foliar biomass was regressed against functional leaf longevity, non-seasonal and seasonal forests fell on a single line, suggesting that the leaf production rate during favorable periods is not substantially different among forests in the world. The gross production of forest ecosystems then can be predicted to a first approximation simply by the annual duration of the period favorable for photosynthetic activity in any given region.
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1 - McGill University, Department of Biology, 1205 Avenue Dr. Penfield, Montreal, Québec, H3A 1B1, Canada
2 - Ishikawa Prefectural University, Laboratory of Plant Ecology, Nonoichimachi, Ishikawa 921-8836, , JAPAN
GPP: Gross Primary Production
Functional leaf longevity
Leaf Mean Labor Time
Leaf Mean Labor Time.
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, August 1st, 2006
Time: 10:30 AM