Wood anatomy of Puerto Rican trees: an ecological archive without tree-rings
In tropical environments of central America, tree-ring forming species are rare to find, especially in areas with pronounced aseasonality, but wood anatomical traits can equally provide important information on species life-histories and response to disturbances. Dating wood anatomical structures remains a crucial task to decipher the ecological information recorded in xylem cellular parameters in absence of defined ring boundaries, particularly to observe the footprint of discrete disturbance events. We present the results of research on 10 species in the Luquillo Forest Dynamics Plot (Puerto Rico, USA). In 2017, hurricane Maria struck the island and caused nearly complete defoliation and high tree mortality, offering us the opportunity to investigate xylem plasticity in response to extensive damage to the forest canopy. We combined high-resolution measurements of diameter growth and anatomical features for 74 individuals to date wood anatomical structures. We related stem radial growth with changes in wood anatomical features and hydraulic conductivity, identifying changes in growth patterns and xylem structures in the pre- and post-hurricane periods. We found shifts in wood anatomy within individuals that were consistent across species and generally reflected increased hydraulic conductivity. We assessed the relationships between xylem traits and species life-histories and highlighted differences in variations of wood anatomy at the species vs. community level. This work helps lay foundations for a broader understanding of the responses of xylem in tropical species to environmental factors and will be expanded in the future to include portions of the island of Puerto Rico with a more pronounced climatic seasonality.