Document Type

Article

Publication Version

Verson of Record

Publication Date

3-13-2007

Keywords

Remote Sensing, Tropical Forest Phenology, Vegetation Climate Interaction

Description

Despite early speculation to the contrary, all tropical forests studied to date display seasonal variations in the presence of new leaves, flowers, and fruits. Past studies were focused on the timing of phenological events and their cues but not on the accompanying changes in leaf area that regulate vegetation–atmosphere exchanges of energy, momentum, and mass. Here we report, from analysis of 5 years of recent satellite data, seasonal swings in green leaf area of ~25% in a majority of the Amazon rainforests. This seasonal cycle is timed to the seasonality of solar radiation in a manner that is suggestive of anticipatory and opportunistic patterns of net leaf flushing during the early to mid part of the light-rich dry season and net leaf abscission during the cloudy wet season. These seasonal swings in leaf area may be critical to initiation of the transition from dry to wet season, seasonal carbon balance between photosynthetic gains and respiratory losses, and litterfall nutrient cycling in moist tropical forests.

Publication Title

Proceedings of the National Academy of Sciences

Volume

104

Issue

12

First Page

4820

Last Page

4823

DOI of Published Version

10.1073/pnas.0611338104

Pages

4

Type

text

Format

application/pdf

Language

en

Publisher

PNAS Proceedings of the National Academy of Sciences of the United States of America

Rights

© 2007 by The National Academy of Sciences of the USA

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