Effect of lianas on forest-level tree carbon accumulation does not differ between seasons: results from a liana removal experiment in Panama

1. Lianas are prevalent in Neotropical forests, where liana-tree competition can be intense, resulting in reduced tree growth and survival. The ability of lianas to grow relative to trees during the dry season suggests that liana-tree competition is also strongest in the dry season. If correct, the predicted intensification of the drying trend over large areas of the tropics in the future may therefore intensify liana-tree competition, resulting in a reduced carbon sink function of tropical forests. However, no study has established whether the liana effect on tree carbon accumulation is indeed stronger in the dry than in the wet season.
2. Using six years of data from a large-scale liana removal experiment in Panama, we provide the first experimental test of whether liana effects on tree carbon accumulation differ between seasons. We monitored tree and liana diameter increments at the beginning of the dry and wet season each year to assess seasonal differences in forest-level carbon a...