Does increasing canopy liana density decrease the tropical forest carbon sink?

The ongoing decline in the American tropical forest carbon sink has
serious ramifications for atmospheric carbon levels and global climate
change. Increasing liana abundance may explain the decaying carbon sink
because lianas reduce canopy tree growth and survival, which limits forest
carbon storage. However, canopy lianas, not solely understory lianas,
would have to be increasing for this hypothesis to be credible because
canopy lianas compete especially intensely with canopy trees. Data in this
archive were used to examine the change in canopy lianas over 10 years on
Barro Colorado Island (BCI), Panama to test three hypotheses. 1) Canopy
lianas are increasing on BCI. 2) Increasing canopy lianas decrease
aboveground canopy tree and forest carbon storage. 3) Lianas are the
numerically dominant and most diverse woody plant growth form in the
canopy. Our findings indicated that lianas are the numerically
dominant and diverse woody plant group in the BCI canopy, and this
dominance is increasing, reducing forest-level carbon storage and possibly
explaining the decaying American tropical forest carbon sink.