Towards forest landscape restoration programs in the Philippines: Evidence from logged forests and mixed-species plantations

Abstract

With only 7.01 million hectares of remaining forested areas in the Philippines, there is an urgency to protect these areas, while also implementing restoration strategies to increase forest cover and improve forest functionality. In this study, we assess how the so called “rainforestation” approach, attempts to implement close-to-nature restoration strategies in humid tropic areas. One of the main objectives of the “rainforestation” approach as a form of a mixed-species plantation is the rehabilitation of structural and floristic integrity similar to natural conditions. We compared study areas located in the provinces of Leyte and Southern Leyte composed of logged forests (temporary plots), with logged forests on a permanent research plot and with mixed-species plantations. Basal area, carbon stocks, volume and biological diversity between study areas were calculated and compared, both for static and dynamic data. Results from the static data indicate that carbon stocks (89.30 t ha−1) and volume (262.56 m3 ha−1) of the mixed-species plantations (“rainforestation” approach) is significantly lower than that of the logged forests. However, when it comes to the capacity of the study areas for potential increments, the mixed-species plantations are not significantly different on basal area increment (0.99 m2 ha−1 yr−1), carbon stock increment (3.67 t ha−1 yr−1) and total volume increment (10.47 m3 ha−1 yr−1) as compared to the logged forests’ capacity (basal area—1.08 m2 ha−1 yr−1, carbon—4.06 t ha−1 yr−1 and total volume—11.98 m3 ha−1 yr−1). The species composition was only partly comparable to logged forests of the region, but overall tree species richness is high in comparison to classical plantation approaches. Previously logged forests are able to recover fast reaching surprisingly high values of carbon stocks and potential commercial timber volume. Our study indicates that “rainforestation” cannot fully replace the functionality of natural forests, but can provide a surprisingly multifunctional tool for landscape restoration, providing both timber and non-timber ecosystem services.