Wood anatomy of Ceiba speciosa (A. St.-Hil.) Ravenna under urban pollution

Abstract

Abstract Urban pollution is one of the current environmental problems which most threatens the human and environmental health. In a fast-changing world, trees stand out among the sessile organisms that withstand the variations imposed by the environment throughout their lifespan. Thus, trees have become important objects of study in the evaluation of phenological, physiological and/or morphological plasticity. Previous studies have demonstrated the impact of urban environment on cambium anatomy and dendrochronology of Ceiba speciosa (Malvaceae), a native species of the Atlantic Forest. In the present study, our objective is to evaluate the impact of the urban environment on wood structure and consequently on the hydraulic architecture of Ceiba speciosa. Wood samples were collected by a non-destructive method, processed and analyzed according to the usual techniques for plant anatomy. Samples were collected in two sites: the first, an important forest remnant of the Atlantic Forest, and the second next to Avenida Brasil, the largest avenue in Rio de Janeiro, the fourth largest city in Latin America. Trees showed plasticity in seven anatomical features and significant differences in wood structure between both groups studied. Urban trees have lower hydraulic conductivity, shorter vessels and fibres, and larger, more frequent rays. These features demonstrate that in stressful situations, such as those observed in urbanized environments, Ceiba speciosa invests in more safety for water transport and in lower wood resistance, with a trade-off between high production of cells of low energy cost and providing storage of water and metabolic products for unfavorable periods.