Long-term changes in liana loads and tree dynamics in a Malaysian forest
Wright SJ; Sun IF; Pickering M; Fletcher CD; Chen Y
The importance of lianas through time and their effect on tree reproduction are evaluated for the first time in a Southeast Asian Dipterocarp forest. In the 50-ha forest dynamics plot at the Pasoh Forest Reserve Malaysia we quantified flower and seed production by lianas and trees for 13 years assessed liana loads in the crowns of all trees larger than 30 cm in diameter at breast height in 2002 and 2014 and assessed levels of reproduction for the same trees during a strong general flowering event in 2014. General flowering refers to synchronous reproduction by hundreds of plant species at irregular multi-year intervals and only occurs in Southeast Asian Dipterocarp forests. Overall lianas were present in 50% of tree crowns and comprised 31% of flower production and 46% of seed production. Lianas reduced growth survival and reproduction by their host trees. Lianas were less frequent in canopy emergent trees Dipterocarps comprised a disproportionately large proportion of canopy emergents and as a consequence lianas were less frequent in Dipterocarps than in trees from other plant families. Lianas infested the crowns of significantly fewer trees in 2014 (47.9%) than in 2002 (52.3%); however the decrease was restricted to trees with the lightest liana loads and sample sizes and statistical power were enormous. Lianas comprised a stable proportion of flower production and a highly variable proportion of seed production from 2002 through 2013. We conclude lianas have a huge impact on trees in this forest and were a stable component of the forest between 2002 and 2014. The emergent habit and associated ability to avoid lianas likely contributes to the success of the Dipterocarpaceae.