Wood and bark water content and monthly stem growth in Amazonian tree species

Abstract

The knowledge of how trees respond to microclimate variability is important in the face of climate changes. The objectives of this study were to examine the variation in wood water content (WWC) and bark water content (BWC) in Amazonian trees, as well as to assess the effect of microclimatic variability on monthly diameter growth rates (DGR). We extracted a core sample from each of 120 trees (28 species) and determined WWC and BWC on a fresh matter basis. DGR was measured monthly during the 12 months of 2007. The effect of microclimatic variability on DGR was analyzed by redundancy analysis. Average BWC and WWC were 53.4% and 34.7%, respectively, with a large variation in stem water content among species (BWC = 36.2−67.1%; WWC = 26.4−50.8%). There was no significant relationship between stem diameter and WWC or BWC, nor between DGR and wood density (p > 0.05). However, wood density was negatively correlated with WWC (r s = −0.69, p < 0.001). The high BWC emphasizes the importance of the bark tissue in Amazonian trees. Contrary to expectations, variability of monthly irradiance, rainfall and temperature had no effect on DGR (p > 0.20). The unresponsiveness of DGR to microclimatic variability, even in an above-average rainy year such as 2007, indicates that other parts of the tree may have greater priority than the stem for carbon allocation during the dry season.

Transpiration of Swartzia tomentifera in response to microclimatic variability in the central Amazon: the net effect of vapor pressure déficit

“…The genus Swartzia (~180 neotropical species, Torke and Mansano, 2009) is important not only for timber production, but also because non-timber products can be obtained from trees of this genus (Sanz-Biset and Canigueral, 2011). The trees of S. tomentifera are of medium stature (up to about 30 m tall), but stem growth is rather slow, 0.96 mm yr -1 (Dias and Marenco, 2021).…”

Stem growth of multipurpose tree species: net effect of micrometeorological variability assessed by principal component regression

“…The increase in stem circumference at breast height of these trees was measured once a month from January 2018 to December 2020 using dendrometer tapes and digital calipers. From these measurements, the monthly increase in diameter was computed, as described by Dias and Marenco (2021). We also measured wood density (WD) (dry mass to fresh wood volume, Dias and Marenco 2016), width of the canopy crown (mean diameter of the ground projected crown), climbed the tree and measured its height (with a tape) and determined the diameter-height relationship.…”