Technical and Financial Analysis of Enrichment Planting in Logging Gaps as a Potential Component of Forest Management in the Eastern Amazon

background

This study investigates the potential for managing timber tree species regeneration in disturbed areas within logged forests in the eastern Amazon through the experimental introduction of seeds and seedlings.

Research Goals & Methods

Seeds and seedlings were planted in logging gaps. Established seedlings were tended (i.e., competing vegetation was removed) after year one and monitored for four years in logging gaps ranging from 165 to 455 m2. These tended gaps were also compared against sample plots of untended gaps. Growth rates from this study and also from previous studies were used to estimate the technical and financial viability of replacing adult trees of high-value species through an enrichment planting silvicultural treatment.

Conclusions & Takeaways

For all species, there was a positive correlation between light intensity and growth rates in logging gaps. Tending in gaps had a greater impact on diameter growth than on height growth, although Cordia goeldiana, Parkia pendula, Tabebuia serratifolia and Tabebuia impetiginosa showed a significant treatment effect for height. Tending also had a greater effect on plant growth in larger gaps. Enrichment planting and the tending of established seedlings to reduce competition and prevent suppression under the developing gap canopy was as important as gap size in creating conditions that assist canopy recruitment. Unless costs can be lowered, time to harvest can be reduced, or timber value increases, the net present values for timber produced through enrichment planting may not provide a financial incentive to implement this treatment. The author suggests refining methods to reduce costs and increase growth rates to make gap enrichment a more viable option for forest managers in Amazonian production forests, along with potential legal protections for high-value species.