Document: MOA-3-30-5

Photosynthetic response of canopy species in a forest area in eastern Brazilian Amazonia.

DIAS-FILHO, M.B.* ¹, J.B.M.GUERRERO ² and D.C.NEPSTAD ³

Embrapa Amazonia Oriental, Belém, PA, 66095, Brazil ¹
Instituto de Pesquisa Ambiental da Amazonia, Belém, PA, 66087, Brazil ²
The Woods Hole Research Center, Woods Hole, MA, 02543, USA ³

Abstract:
The functional changes to experimental rainfall exclusion of a one-hectare area of primary forest in the State of Para, Brazil, will be studied during a three-year period. The objective of the present study was to gather baseline data on the photosynthetic response of canopy (> 10m) species in the area, prior to implementation of the rainfall exclusion treatment. Measurements on individual species were made during the rainy and dry seasons of 1999, between 8:30h and 15:30h, local time, with an open portable photosynthesis system (Li-Cor LI-6400) under standard conditions. Wood towers provided access to the high forest canopy. Mean PPFD during gas exchange measurements were 212.1 323.2 (mean standard deviation) and 298.1 455.7 mol m² s¹ for the rainy and dry seasons. Mean photosynthetic rates for the rainy and dry seasons were 5.37 2.73 and 7.62 3.96 mol m² s¹, and maximum photosynthetic rates were 21.1 and 22.7 mol m² s¹.

Keywords: rain forest, photosynthesis, canopy

This abstract is being presented at: 10:30 AM in session:
Poster Session #1: Light Relations.