ABSTRACT This work describes the anatomical analysis of the wood of four Caatinga tree species in order to determine the anatomical characteristics necessary for species segregation in functional groups, to relate them to the regional environmental conditions, as well as to infer about their management and conservation. Qualitatively, the species showed peculiar adaptations to xeric environments such as high frequency of low caliber vessels or parenchyma cells. Quantitatively, the four taxa were divided into three functional groups related to the precipitation and temperature of the Caatinga. The relationships between anatomy and the environment have shown their vulnerability to climatic variations, and have warned of the damage that can be generated by anthropogenic action. It is advisable to use the energy of the species or for use in civil construction, with the exception of Tabebuia aurea, which is appropriate for carpentry. It was verified that the anatomy of the wood has potential as a subsidy for the use, management and conservation of the studied species.

Resumo Este trabalho verificou a influência das condições ambientais na estrutura do xilema secundário da espécie Caryocar brasiliense Camb. (pequizeiro) através de um estudo anatômico comparado do lenho de árvores procedentes de fisionomias de cerradão e cerrado s.s., no município de Santa Rita do Passa Quatro, SP. As características do lenho foram analisadas qualitativa e quantitativamente, sendo as últimas comparadas pela análise de variância, bem como por análises multivariadas de agrupamentos e componentes principais. A análise de variância demonstrou existir diferenças significativas para oito das dezesseis variáveis analisadas, bem como uma grande variação entre árvores da mesma localidade, aspecto corroborado pela análise de agrupamentos. A matriz de correlação entre variáveis indicou, de modo geral, relações inversas entre dimensões longitudinais e radiais dos elementos anatômicos. Pode-se inferir pela variabilidade significativa entre árvores que a diferenciação das fisionomias ocorre de forma gradual, não se observando um conjunto de características anatômicas suficientemente marcantes que tipifiquem as fisionomias estudadas.

Abstract This study aimed to verify the influence of ambient conditions on the structure of secondary xylem of Caryocar brasiliense Camb. (“pequizeiro”) through a comparative anatomical study of two populations belonging to “cerradão” and “cerrado s. s.” (Brazilian savannas), in the city of Santa Rita do Passa Quatro, São Paulo. The wood was described qualitatively, and quantitative data were analyzed using analysis of variance, as well as multivariate and principal components analysis. The analysis of variance showed significant differences for eight out of sixteen anatomical parameters, as well as great variation between trees of the same locality, an aspect corroborated by multivariate analysis. The correlation matrix showed generally inverse correlations between longitudinal and radial measurements of the anatomical characters. Based on the significant variability found between trees we can infer that the differentiation of the formations occurs gradually, since a marked set of anatomical characters that would individualize each type of vegetation was not observed.