Differences in biomass allocation, light interception and mechanical stability between lianas and trees in early secondary tropical forest

Abstract

Summary 1In early secondary successional forest, we analysed whether lianas convert mass more efficiently to height increment and leaf production, thus enabling them to capture more light per unit mass than trees. 2Vertical biomass distribution, plant height, stem properties and crown structure were measured for individual plants of three short-lived pioneers (SLP), four long-lived pioneers (LLP) and three lianas in a 0·5 and 4-year-old secondary forest stand. Daily light interception per individual (Φp), and mean light interception per unit of leaf area (Φarea), leaf mass (Φleaf mass) and total above-ground mass (Φmass) were calculated with a canopy model. 3In the 0·5-year-old stand lianas were mostly self-supporting and exhibited similar above-ground biomass allocation to height growth as trees. At this stage lianas were not more efficient in terms of light interception per unit mass (Φmass). In the fourth year lianas were mostly climbing and were taller relative to their mass, but exhibited lower buckling safety factors (BSFs). Their Φmass values became higher than those of the LLP, and equal to that of the SLP, Cecropia. The difference with the LLP was because the lianas captured more light per unit leaf area (Φarea) while they had a similar leaf area per unit mass (LAR: Φmass = LAR × Φarea). 4These results show that as lianas go from being freestanding to climbing, they improve their chances to harvest light at lower mass investments in above-ground parts than the LLP but not SLP trees. At the same time, lianas have leaf traits similar to the LLP, which may enable them to persist at lower light availability.