El Bosque de Pterocarpus

Approximately 300 species of vines occur in Puerto Rico. The vine is a climbing plant with long flexible stems that intertwine the branches of trees and use other plants as a support.

Vines extend their branches over and through the trees, thus reaching the sunny areas of the forest canopy. Their stems, provided with broad water-conducting elements and a low accumulation of wood, lack enough fiber to stay erect, so they depend on different appendages, such as tendrils, to support themselves on neighboring trees.

The abundant growth of lianas and vines in the Pterocarpus forest not only characterizes its appearance but also affects environmental conditions. In their struggle for land, space for the rakes and for illuminated air space for the leaves, the vines compete with the trees, including Pterocarpus officinalis. As we already pointed out, of the leaves exposed to the sun in the canopy and the sides of the forest, a large portion belongs to the climbing plants.

The trees, because of their fixed disposition and rigid growth, compete with each other for domination of the canopy of the forest. The vines and lianas, due to their flexibility, have greater freedom for growth and are opportunistic. They can grow in several directions by rapidly lengthening their stems and monopolizing advantageous positions to expose their leaves to the sun, often to the detriment of the tree that supports them. Vines, growing up entangled on the trunks of trees, can interfere in the uninhibited growth, often causing abnormalities and deformities in them. As a result, the timber value of those
trees is altered and reduced. In some cases, the climbing vines can dominate the tree’s fronds, limit the tree’s growth and cause it to fall.

In this sense, these plants can function as a selective control over the development possibilities of different species and, therefore, constitute a relevant factor to consider in the management of a forest.

Climbing plants are much more abundant in tropical forests than in temperate forests, particularly in low elevation forests, such as Pterocarpus in Humacao, where they grow well.

The dominant species of vine in the Pterocarpus Forest is the Woody Vine (Bejuco Lenoso in Spanish). Scientific name: Trichostigma octandra. 

In terms of human uses, the huts of the Taínos were built of vines and straw, among other uses that our indigenous ancestors gave these plants.