Effects of experimental lightgaps and topography on enrichment plantings in a central Amazonian secondary forest

Abstract

Enrichment plantings into secondary forest are an important option in restoring species diversity and ecosystem services. However, little attention has been given to environmental requirements for species performance. This study evaluated the effects of lightgaps and topographic position on the growth and survival of four native tree species (Pouteria caimito, Garcinia macrophylla, Dipteryx odorata and Cynometra bauhiniaefolia) planted into a 26-year old secondary forest originating from abandoned pastures in the central Amazon Basin. Artificial lightgaps and control plots under closed canopy were uniformly distributed on plateaus and bottomlands near water bodies. Seedlings were planted randomly into the plots and monitored for 28 months. Seedling survival rate was high (93%) and did not differ among species. Overall, lightgaps produced a 38% increase in seedling height relative to the controls. Although the four species naturally occur in mature forest, two of the four grew significantly more in lightgaps than in closed canopy secondary forest. Overall, bottomlands facilitated greater seedling growth in height (38%) relative to plateaus, but only one species exhibited a significant increase. This study shows the importance of the environmental variability generated with canopy openings along the topographic gradient, suggesting that both the selection of species and microsite conditions of planting sites have to be considered important criteria in the recovery of degraded areas.

Monitoring recovery of tree diversity during tropical forest restoration: lessons from long-term trajectories of natural regeneration

“…Third, maximizing recovery of species diversity may require silvicultural interventions within plots to reduce abundance of dominant species, control the spread of invasive species, or to increase microhabitat heterogeneity [59,60]. Enrichment planting of locally adapted tree species (often accompanied by silvicultural treatments) can also be a useful approach to boost site-level species richness and diversity [60][61][62].…”

Wind Energy Resource Assessment Based on WRF Model and Key Model for Micro-site Selection of Wind Farms

“…Overall, the light gap increased seedling height by 38% compared to the control. Although these four species occur naturally in mature forests, two of the four species grow significantly more in light gaps than in the closed canopy of secondary forests [5]. These studies provide another basis for the site selection operation of practical projects.…”

Canopy openness modifies tree seedling distributions along a tropical forest elevation gradient

“…The influence of canopy shade versus open conditions on seedling establishment and forest regrowth is well established (Whitmore 1986, Brown and Whitmore 1992, Kobe et al 1995, Bentos et al 2020, Zhang and Yi 2020). Numerous studies have noted how different tree species possess distinct abilities to establish, grow and survive with and without canopy shade (Chazdon et al 1988, Clark et al 1996, Denslow and Guzman 2000, Kitajima et al 2005, Poorter 2005, Sheil et al 2006).…”