The use of exotic species in reforestations is one of the highly criticized forest policies in the Philippines, mainly due to their perceived negative impacts on biodiversity conservation. To ascertain the influence of exotic plantations on native flora establishments, we inventoried the structure, composition, and diversity of understory woody regeneration in three exotic stands in Southern Philippines and compared them to adjacent second growth forest. The mean total density of regeneration did not differ significantly among the stands, except for the separate density of saplings and seedlings where natural forest had significantly the lowest and highest density, respectively, over the exotic stands. Teak (Tectona grandis L.) and mangium (Acacia mangium Willd.) stands generally had the bigger basal area, indicating the dominance of saplings in these areas. A low diversity characterized the four stands with the lowest and highest diversity indices observed, respectively, in the mahogany (Swietenia macrophylla King) and natural forest. Despite their proximity, each stand exhibited uniqueness in species composition, with some of the endangered species observed only in the exotic stands. Therefore, it would be interesting to know how continued protection of these stands would affect the trajectory of succession of native species over time.

It remains unknown whether there are available gall rust resistant seed sources of Falcata (Falcataria moluccana (Miq.) Barneby & J.W.Grimes) in the country or elsewhere. This study was conducted to obtain baseline data for future progeny selection of gall rust resistant clones of Falcata in the region. The objectives were to determine whether there are available seed sources or mother trees in the region that are resistant to gall rust, and whether gall rust infection has negative effects on the growth of Falcata. The trial (with 130 mother trees as treatments and four replications) was assessed in November 2020- or five-years following establishment in 2015. Mean percent incidence (15.0 ± 5.0% to 80.0 ± 14.1%) and severity (3.75 ± 1.25%) to 35.0 ± 16.95%) of gall rust varied significantly among treatments indicative of genetic diversity among mother trees. The incidence ranged from ‘occasional’ to ‘widespread’ while severity ranged from ‘low’ to ‘high’ with mother trees 99 (Mutia, Zamboanga del Norte) and 106 (Magsaysay, Baliangao, Misamis Occidental) emerged as the most resistant of all. Height and diameter were positively related to gall rust incidence and treatments only, although none of the mother trees with resistant traits had superior growth. There was however indication of growth and disease tolerance tradeoff where trees with higher gall rust incidence tend to grow bigger perhaps to compensate for any negative impacts from gall rust infection.