Treesearch

Successive inventories in Puerto Rico provided the first estimates of secondary forest growth on a regional basis. The volume of growing stock trees increased by 32%, and timber volume by nearly 36%, on all classes of forest land between 1980 and 198.5. Timber volume growth rates (in m’ha-’ yr-’ ) varied by forest class and averaged 2.0 in young secondary forest, 6.9 in advanced secondary forest, 7.1 in abandoned coffee shade forest, and 1.2 in active coffee shade forest. Tree diameter growth rates were weakly correlated with initial tree diameter (r ’ = 0.16, n = 1090). A slight increase...

This paper describe the hydraulics of unsubmerged flow for 5 culverts in the Luiquillo Esperimental Forest of Puerto Rico. A General equation based on empirical data is presented to estimate culvert discharge during unsubmerged conditions. Large culverts are needed in humid tropical montane areas than in humid temperatute watersheds and are usually appropriate only for drainage less than 1km2.

Knowledge of the lifespans of wild birds is of both aesthetic interest and scientific importance. The accumulation of such knowledge can be accomplished almost solely through the bird banding process. Clapp et al. 11982,1983), Klimkiewicz et al. 11983), and Klimkiewicz and Futcher (1987) have recently summarized longevity records for North American birds through a survey of the Bird Banding Laboratory's records.

Based on more than 2000 total captures of 40 species of birds in 14 avian families, resulting from 15 yr of banding at a single net line in southwestern Puerto Rico, body mass and wing length measurements of 246 individuals of 25 species of birds that were captured and recaptured 612 times were used to show that: (1) Among and within different individuals, temporal variation in selected avian morphological characters is minimal when measurements are taken at the same time of year. (2) Measuring instruments widely used in the field are precise. (3) Sampling techniques are comparable. (4)...

Ants of the tribe Attini (fungus grower) collect different organic materials that are used to grow a fungus. It was thought that the fungus mycelium was the only source of nutrition for these ants, but Quinlan and Cherrett found that Atta cephalotes (L.) squeezes oils from fresh leaves and uses them as food. These oils supplement the fungus material eaten by this species. Members of the genus Atta are considered pests in some agricultural crops, pasture land, and forest seedling plantations. There are no Atta ants in Puerto Rico and adjacent islands, but four species of the attine tribe...

Plantation growth of mahogany (Swietenia spp.) and teak (Tectona grandis) and the performance of teak and Spanish cedar (Cedrela spp.) provenances located in subtropical dry and moist life zones. are summarized for St. Croix, U.S. Virgin Islands. Hybrid mahogany (S. macrophylla x S. mahagoni) from St. Croix had the best form and growth rate of all tree species tested. The surviving five provenances showed 39 and 59 percent survival at 16 years in Estate Thomas and Hams Bluff, respectively. Growth rates for the Belize provenance at Estate Thomas and the Mexican provenance at Hams Bluff were...