Hydraulic and structural traits of trees across light gradients in the Amazon secondary forest.

Autor:	Coelho-Silva D; Department of Forest Science, Soil and Environment, São Paulo State University, School of Agricultural Sciences, Botucatu, São Paulo, Brazil., Guimarães ZTM; Coordination of Environmental Dynamics, National Institute of Amazon Research, Manaus, Amazonas, Brazil., Podadera DS; Department of Forest Science, Soil and Environment, São Paulo State University, School of Agricultural Sciences, Botucatu, São Paulo, Brazil., Modolo GS; Coordination of Environmental Dynamics, National Institute of Amazon Research, Manaus, Amazonas, Brazil., Rossi S; Laboratoire sur les écosystèmes terrestres boréaux, Département des Sciences Fondamentales, Université du Québec à Chicoutimi, Chicoutimi (QC), Canada., Ferreira MJ; Department of Forest Sciences, Federal University of Amazonas, Manaus, Amazonas, Brazil., Marcati CR; Department of Forest Science, Soil and Environment, São Paulo State University, School of Agricultural Sciences, Botucatu, São Paulo, Brazil.
Jazyk:	angličtina
Zdroj:	Tree physiology [Tree Physiol] 2024 Nov 14. Date of Electronic Publication: 2024 Nov 14.
DOI:	10.1093/treephys/tpae146
Abstrakt:	Amazonian species are generally unable to adapt to long drought periods, indicating a low capacity to adjust their hydraulic traits. Secondary forests account for 20% of forest cover in the Amazon, making natural regeneration species crucial under climate change scenarios. In this study, we compared the hydraulic traits of five species, including non-pioneers (Bertholletia excelsa Bonpl., Carapa guianensis Aubl., Hymenaea courbaril L.) and pioneers (Cedrela fissilis Vell., Tabebuia rosea (Bertol.) Bertero ex A.DC.), across light conditions (understory, intermediate, gap) in a 22-year-old secondary forest in Central Amazon, Brazil. Twenty-five saplings were planted and monitored in 3 plots × 5 blocks. Five years after the plantation, we assessed growth, wood density, leaf water potential at predawn and midday, xylem embolism resistance (P50), and hydraulic safety margins (HSM). Leaf water potential ranged from -2.9 to 0 MPa. The non-pioneer species C. guianensis and H. courbaril exhibited the lowest P50 (-4.06 MPa), indicating higher embolism resistance, whereas the pioneer T. rosea had the highest P50 (-1.25 MPa), indicating lower resistance. HSM varied from -1.60 to 3.26 MPa, with lower values in gap conditions during the dry period (-1.60 MPa), especially affecting pioneer species. Wood density was influenced by both light and species type, with non-pioneers showing generally higher density, with H. courbaril reached 0.75 g cm-3 in the understory while the pioneer T. rosea showed the lowest density (0.27 g cm-3). These results highlight that light conditions affect hydraulic traits differently across species strategies, especially during early growth. Non-pioneer, slow-growing native species appear more resilient to light variation, making them suitable for future plantations aimed at climate adaptation in secondary forests. (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)
Databáze:	MEDLINE
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