Natural restoration of native forest in a Caribbean pine plantation

Due to easy establishment and rapid growth, Caribbean pine (Pinus caribaea) has been used extensively in reforestation in the tropics. Degraded slopes (15 - 45%) surrounding the Caracas campus of Universidad Simón Bolívar, Venezuela (1,250 masl; 22°C and 944 mm) have been reforested with this pine 35 years ago. High initial planting density (up to 1,360 trees/Ha), short pine longevity, several fires, and lack of natural regeneration are increasing pine mortality. Due to the importance to protect the University campus from slope erosion and washouts, a project to restore the native forest is in progress. One of the treatments is to allow natural colonization of pine stands (400 m²) by woody species from a neighbour native forest with 88 – 100 tree species from 45 families. Natural colonization occurs first and faster in stands where pine mortality was highest due to higher irradiance as well as along depressions due to higher humidity. After grass (Melinis minutiflora) and fern (Cyatheaceae) initial establishment, the first woody colonizers, are well known tropical pioneer plants. In order of importance, thedy are:  Melastomataceae (Miconia spp.), Clusiaceae (Clusia spp.), Guttiferae (Vismia sp), Asteraceae (Oyaedea sp and Pollalesta sp), Euphorbiaceae (Croton sp), Clethraceae (Clethra sp), Fabaceae (Inga sp), Cecropiaceae (Cecropia sp) and Tiliaceae (Heliocarpus sp). At present, studies are focused on several treatments to increase colonization rate and spread as well as to select potential long lived species from the neighbouring montane forests.