Respostas anatômicas da madeira às variações fitofisionômicas da Mata Atlântica

Abstract

The analysis of functional attributes of wood plays a fundamental role in assessing future strategies for tropical forest preservation. Understanding how wood anatomy contributes to species resilience becomes crucial for predicting the effects of climate change on the structure of trees in different phytophysiognomies of the Atlantic Forest. Dense Ombrophilous Forests (DOF), Seasonal Semideciduous Forests (SSF), and Restingas (RES) are phytophysiognomies that make up the vegetation mosaic of the Atlantic Forest. However, environmental conditions related to water availability and irradiance in these phytophysiognomies vary. In this sense, it is possible to observe a water and irradiance gradient, with DOF being the wettest phytophysiognomy, with lower irradiance and clayey soil, RES being the driest, with higher irradiance and sandy soil, and SSF having intermediate conditions. These microclimatic differences among these phytophysiognomies can directly influence species distribution, reflecting in their anatomical characteristics and functional wood attributes. Species occurring in drier phytophysiognomies, such as SSF and RES, need to invest in strategies to restrict water loss and increase water storage. In contrast, species living in wetter phytophysiognomies, such as DOF, do not need to expend energy on attributes restrictive to water loss and only concern themselves with their growth. Thus, the present study aims to description the anatomy and identify the functional attributes of wood in the most abundant species, relating them to variations in soil water availability and irradiance among these phytophysiognomies. For this purpose, 15 species were selected for wood collection. Anatomical characteristics of the species were described, and morphoanatomical parameters of wood were evaluated (vessel frequency, diameter, and lumen; fiber length and thickness; and length of pits, total parenchyma, and rays; and tissue percentages). Additionally, soil characteristics (chemical and granulometric) were assessed. Results indicated that species have distinct anatomical traits; in DOF, they exhibit an architecture geared towards efficient water transport, with higher theoretical hydraulic conductivity and lower wood density. On the other hand, species from SSF and RES show more conservative attributes, reflecting a secure hydraulic architecture adapted to conditions of lower water availability. These results highlight species adaptation to the specific conditions of each phytophysiognomy. Plants in humid phytophysiognomies, such as DOF, are more vulnerable to climate change due to higher water demand, while plants in dry phytophysiognomies, like RES, have strategies that offer greater survival security. In addition to the anatomical description of wood from uncataloged species, their anatomical attributes provide important insights into understanding species responses to variations in water availability, assisting in predicting the effects of climate change on plant communities, and implementing appropriate conservation strategies in the Atlantic Forest.