Effect of liana cutting on water potential and growth of adult Senna multijuga (Caesalpinioideae) trees in a Bolivian tropical forest

Abstract

Lianas, or woody climbing plants, are a major constituent of seasonally dry tropical forests, and are thought to impact negatively their host trees. In this study we evaluated whether liana presence was associated with reduced leaf water potentials and growth in adult Senna multijuga trees during the dry season in a lowland Bolivian forest. We used leaf water potentials in trees as a first approach to assess trees' water status, under the assumption that leaf water potentials become more negative when water losses (via transpiration) exceed gains (by uptake). We measured relative growth in girth at 1.5 m height (gbh) to quantify tree growth. At the beginning of the 1996 dry season (early June), we selected 20 S. multijuga trees 10-20 cm dbh, and measured their gbh. We also recorded pre-dawn and mid-day leaf water potentials in these trees. In ten experimental trees all lianas were then cut, while the remaining trees were used as controls. Pre-dawn and mid-day water potentials were re-measured 1 day after liana-cutting, and then every week in all trees for 1 month and then at 3 and 5 months, until the beginning of the next rainy season (November); gbh was measured again in July 1997 to estimate relative growth rate. Liana removal was associated with less negative pre-dawn (-0.3 vs -0.4 MPa) and mid-day (-0.5 vs -0.7 MPa) water potentials in trees during the dry season. This difference appeared as early as 1 day after cutting, and disappeared once the rainy season began. Liana-cut trees grew more (0.4 mm/mm year) than liana-uncut trees (0.2 mm/mm year). These findings suggest that lianas may interfere with water availability to these trees during the dry season, and may also hinder tree growth.

Effects of Understory Liana Trachelospermum jasminoides on Distributions of Litterfall and Soil Organic Carbon in an Oak Forest in Central China

“…The finding that liana strongly affected the distribution pattern and decomposition degree of surface litter supports the conclusion that the spatial heterogeneity of forest floor litter is regulated by the distribution of trees as well as the understory plants [27,28]. The differences in litter …”

“…The finding that liana strongly affected the distribution pattern and decomposition degree of surface litter supports the conclusion that the spatial heterogeneity of forest floor litter is regulated by the distribution of trees as well as the understory plants [27,28]. The differences in litter components between stands with different densities of liana were attributed to the physical and biological characteristics of the liana plant [14,29].…”

Lianas have a greater competitive effect than trees of similar biomass on tropical canopy trees

“…Reduced below-ground liana competition may be particularly important during seasonal drought when declining soil moisture availability may limit canopy tree uptake, because lianas continue to grow and take up below-ground resources during this period (Andrade et al 2005, Schnitzer 2005). For example, in a seasonal forest in Bolivia, Pérez-Salicrup and Barker (2000) reported that cutting lianas at the beginning of the dry season resulted in unchanging pre-dawn water potential for canopy trees throughout the dry season, whereas pre-dawn water potential for canopy trees with lianas present declined during Fig. 2.…”

Factors Influencing Liana Species Richness and Structure following Anthropogenic Disturbance in a Tropical Forest, Ghana

“…Lianas may help maintain tree diversity in the forest by causing tree falls which could reduce the dominance of tree species [4]. Heavy liana loads on trees can cause mechanical damage of the hosts and also reduce their growth rates [5,6]. Additionally, lianas could impact negatively on natural regeneration of trees in forest ecosystems [7].…”