Long-Term Effects and Carbon Stock of Exploitable Plant Species after Enrichment Planting in the East Region of Cameroon

Abstract

An increase in the human population causes deforestation, affecting tropical forests’ sustainability. Enrichment planting is the restoration of over-exploited and secondary forests in order to increase the total tree volume and economic value of forests. The purpose of this article was to present the results of enrichment plantings of exploitable species in the East Region of Cameroon. This study was carried out in Log yards (LYs), Skid trails (STs), and under forest canopy in some forest concessions. The seedlings of 15 most exploitable species in Cameroon were selected and planted in 30 enriched plots. A transect of 4 × 50 m2 was established using a line spacing of 5 × 5 m. The height and diameter of each exploitable seedling species were measured 1.5 and 10 years after enrichment planting. A total of 1288 individuals of 15 species belonging to 8 families were recorded. The most important species was Erythrophleum sauveolens (183.1) that regenerated naturally in the LYs. The most important families were the Fabaceae and Malvaceae. A year and ten years after enrichment planting, growth was highest in the LYs as compared to the STs. Generally, annual mortality was highest in STs, while annual survival was highest in LYs. This may be due to the availability of light after canopy destruction. However, biomass was highest under the forest canopy in the first year, the same for both LYs and STs in the 5th year, and highest in the LYs in the 10th year. Carbon stock, though low, increased over time, with a Carbon stock of 0.004 t/ha ten years after enrichment planting. The species Triplochiton scleroxylon had the highest Carbon stock due to silvicultural management of its plots, emphasizing the necessity of site-species matching before enrichment planting and post-planting silvicultural management for effective forest restoration.