Censusing and measuring lianas: a quantitative comparison of the common methods
Schnitzer SA; DeWalt SJ; Chave J
Lianas contribute to many aspects of tropical forest diversity and dynamics and interest in liana ecology has grown substantially in recent years. Methods to census lianas and estimate biomass however differ among studies possibly hindering attempts to compare liana communities. At Nouragues Research Station (French Guiana) we tested the extent to which liana abundance basal area and estimated biomass differed depending on stem diameter measurement location inclusion of ramets inclusion of lianas rooted within versus passing through the plot and plot shape. We found that the mean per plot abundance and basal area of lianas were significantly greater when lianas were measured low on the stem when ramets were included and when lianas were sampled in transects (2 vó 50 m) than in square plots (10 vó 10 m). Mean per plot liana abundance and basal area were 21 percent and 58 percent greater when stems were measured at the largest spot on the stem compared to 130 cm from the ground respectively. Including liana ramets increased average per plot liana abundance basal area and estimated biomass by 19 17 and 16 percent respectively. To facilitate cross-study comparisons we developed conversion equations that equate liana abundance diameter and basal area based on the measurements taken at four different stem locations. We tested these equations at Lambir Hills National Park Malaysia and found that they did not differ significantly between the two sites suggesting that the equations may be broadly applicable. Finally we present a new allometric equation relating diameter and biomass developed from 424 lianas from five independent data sets collected in four countries.