Lianas in a subtropical Atlantic Forest: Host preference and tree growth
Forest Ecology and Management
Determinants of liana abundance on several canopy tree species and the impact of liana abundance on host tree growth were studied in a subtropical Atlantic Forest in northeastern Argentina. Six permanent 1 ha plots were located in a native forest stand. In three of those plots all lianas were cut and allowed to decompose in situ, while the other three plots were used as a control treatment. Liana richness, abundance and climbing mechanisms were studied in seventeen 20 m x 20 m subplots inside the 1 ha control plots. A total of 841 liana stems larger than 1 cm diameter were registered in the 0.68 ha sample area, representing 47 species. Lianas belonging to the Bignoniaceae and Fabaceae families were the most abundant, corresponding to 49.4 and 16.6% of all individuals, respectively. The most common climbing mechanism observed was coiling tendrils, representing the 61.1% of all individuals. Lianas scrambling and twining were represented by 19.6 and 15.6% of the individuals, respectively. The number of lianas climbing a tree was inversely correlated with host tree trunk length. Bark characteristics also played a role on the degree of liana infestation. Some tree species hosted several lianas and the larger the diameter of the largest liana in a host tree the greater was the number of climbing lianas. Facilitation was hypothesized to explain this pattern meaning that many lianas used other lianas climbing a tree for reaching the upper canopy. Tree stem diameter growth was more than 100% lower in two out of the four species studied for liana-laden than for liana-free trees. Results lend support to the hypothesis that cutting of lianas from selected host trees can be used as a forest management technique to enhance tree growth and decrease the length of cutting cycles in native forest stands.