Abstract. Hernandez JO, Ata JP, Combalicer MS. 2022. Long-term changes in floristic diversity, composition and stand structure in Acacia auriculiformis plantation in Mount Makiling Forest Reserve, Philippines. Biodiversitas 23: 3631-3638. There have been continuous debates about whether exotic tree plantation facilitates vegetation succession. In the Philippines, the potential for the re-establishment of native plant communities and improvement of the plant community structure under exotic tree plantations has not yet been evaluated adequately. Thus, the study investigated the dynamics in floristic diversity, composition and stand structure of a reforested area using Acacia auriculiformis Benth. in Sitio Kay Inglesia, Mount Makiling Forest Reserve (MMFR), Philippines. The changes in basal area, stem density, biomass growth, species diversity, species evenness and richness, and canopy closure were determined between two study periods, i.e., 1993-2008 and 2009-2019. Results revealed significant changes in stem density (i.e., 1324 to 2135 trees ha-1) and canopy closure (i.e., 18% to 10%) for mature trees and seedlings/saplings in 2009-2019. The changes in basal area and aboveground biomass were not significant between the two study periods. The species richness was significantly higher in 2009-2019 (i.e., 55 species) than in 1993-2008 (i.e., 22 species). The species diversity also significantly increased from low (i.e., H' = 1.99, S = 23) to moderate (i.e., H' = 2.88, S = 55). Moreover, the number of exotics decreased (i.e., 60 to 40% or 15 to 9 species) as the number of native ones increased (i.e., 27 to 72% or 15 to 40 species). Therefore, the findings of the present study show that re-establishment of native species is possible when restoring degraded land with A. auriculiformis plantation. However, monitoring studies on other key ecosystem attributes (e.g., ecosystem functionality, external exchanges, structural diversity) of the plantation are recommended to enhance our understanding of the species' potential for restoration.

Abstract. Hernandez JO, Tolentino CA, Quiñones LAE, Villancio GB, Maldia LSJ, Combalicer MS. 2021. Growth and morpho-physiology of Tectona philippinensis under different water stress and soil conditions. Biodiversitas 23: 507-513. Plants exhibit adaptive mechanisms to respond to fluctuating amounts of soil moisture and poor soil properties; however, these mechanisms remain largely unknown in many forest tree species growing in dry and limestone areas in the Philippines, such as the endemic and endangered Tectona philippinensis Benth & Hook.f. This study investigated the growth and morpho-physiological responses of T. philippinensis wildlings to water stress and soil types. One-year-old wildlings were subjected to two watering treatments, i.e., well-watered and water-stressed, and three different soil types, i.e., Lobo, Batangas, Mt. Makiling Forest Reserve, and UP-Laguna-Quezon Land Grant. The root collar diameter, height, biomass allocations, and morpho-physiological traits (photosynthesis, stomatal conductance, transpiration, relative water content, specific leaf area, and stem green density) were measured. Overall, the growth performance of the wildlings was improved significantly when grown in soil from the natural habitat under WW conditions. Therefore, the recommended conservation approach potentially suitable for T. philippinensis is in-situ, particularly in riparian areas, when artificial irrigation is not possible and practical. The present study's findings provide us with a better understanding of the growth and ecophysiology of T. philippinensis under water-deficient conditions for its effective in-situ conservation.