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Determining population demographic rates is fundamental to understanding differences in species' life‐history strategies and their capacity to coexist. Calculating demographic rates, however, is challenging and requires long‐term, large‐scale censuses. Body size may serve as a simple predictor of demographic rate; can it act as a proxy for demographic rate when those data are unavailable? We tested the hypothesis that maximum body size predicts species' demographic rate using repeated censuses of the 77 most common liana species on the Barro Colorado Island, Panama (BCI) 50‐ha plot. We found that maximum stem diameter does predict species' population turnover and demography. We also found that lianas on BCI can grow to the enormous diameter of 635 mm, indicating that they can store large amounts of carbon and compete intensely with tropical canopy trees. This study is the first to show that maximum stem diameter can predict plant species' demographic rates and that lianas can attain extremely large diameters. Understanding liana demography is particularly timely because lianas are increasing rapidly in many tropical forests, yet their species‐level population dynamics remain chronically understudied. Determining per‐species maximum liana diameters in additional forests will enable systematic comparative analyses of liana demography and potential influence across forest types. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article about poison ivy's biomass and toxicity responses published in the previous issue.

Hydraulic traits are important for woody plant functioning and distribution. Associations among hydraulic traits, other leaf and stem traits, and species' performance are relatively well understood for trees, but remain poorly studied for lianas. We evaluated the coordination among hydraulic efficiency (i.e., maximum hydraulic conductivity), hydraulic safety (i.e., cavitation resistance), a suite of eight morphological and physiological traits, and species' abundances for saplings of 24 liana species and 27 tree species in wet tropical forests in Panama. Trees showed a strong trade‐off between hydraulic efficiency and hydraulic safety, whereas efficiency and safety were decoupled in lianas. Hydraulic efficiency was strongly and similarly correlated with acquisitive traits for lianas and trees (e.g., positively with gas exchange rates and negatively with wood density). Hydraulic safety, however, showed no correlations with other traits in lianas, but with several in trees (e.g., positively with leaf dry matter content and wood density and negatively with gas exchange rates), indicating that in lianas hydraulic efficiency is an anchor trait because it is correlated with many other traits, while in trees both efficiency and safety are anchor traits. Traits related to shade tolerance (e.g., low specific leaf area and high wood density) were associated with high local tree sapling abundance, but not with liana abundance. Our results suggest that different, yet unknown mechanisms determine hydraulic safety and local‐scale abundance for lianas compared to trees. For trees, the trade‐off between efficiency and safety will provide less possibilities for ecological strategies. For lianas, however, the uncoupling of efficiency and safety could allow them to have high hydraulic efficiency, and hence high growth rates, without compromising resistance to cavitation under drought, thus allowing them to thrive and outperform trees under drier conditions. [ABSTRACT FROM AUTHOR]

Lianas in tropical forests compete intensely with trees for above- and belowground resources and limit tree growth and regeneration. Liana competition with adult canopy trees may be particularly strong, and, if lianas compete more intensely with some tree species than others, they may influence tree species composition. We performed the first systematic, large-scale liana removal experiment to assess the competitive effects of lianas on multiple tropical tree species by measuring sap velocity and growth in a lowland tropical forest in Panama. Tree sap velocity increased 60% soon after liana removal compared to control trees, and tree diameter growth increased 25% after one year. Although tree species varied in their response to lianas, this variation was not significant, suggesting that lianas competed similarly with all tree species examined. The effect of lianas on tree sap velocity was particularly strong during the dry season, when soil moisture was low, suggesting that lianas compete intensely with trees for water. Under the predicted global change scenario of increased temperature and drought intensity, competition from lianas may become more prevalent in seasonal tropical forests, which, according to our data, should have a negative effect on most tropical tree species.