When a mature or climax tropical rainforest is logged or destroyed by a natural catastrophe such as fire or volcanic eruption, how long does it take for it to fully recover to its original state?
The answer is not fully known for a number of reasons. First, there are few people interested in (or have the patience of) monitoring the development of a forest from the various seral to the climax stages.
Second, people often do not live long enough to maintain the clarity of mind required to document the changes. So our knowledge of forest recovery is based on few observations at some point in time, and by extrapolating backward, the full course of development of a forest can be reconstructed.
An example is the tropical rain forest in the vicinity of the volcano Krakatau in Indonesia, which blew its top in August 1883, completely destroying the forest in the vicinity of the volcano. On a visit to Krakatau in 1983, I saw that this forest appeared to have recovered after 100 years or even earlier.
My son Ely, our friend Dr. Rolando del Carmen, and I visited Lake Balanan in the uplands of Siaton in southern Negros a few days ago. I was amazed that the tropical rainforest surrounding the lake was very different from the forest we used to visit for our field studies on Philippine vertebrates in the early 1950’s.
The forest trees consisting mostly of water-adapted species, and mainly belonging to the fig Family, had grown to heights of 20 to 30 meters from the five-meter young trees that I saw some 60 years ago.
The forest now is a typical tropical rainforest characterized by abundance of ferns and mosses, a cool environment, and a closed forest canopy that completely shields the forest floor from light.
These environmental conditions are conducive to growth of a variety of tropical plant species and their associated animal species. The main natural factor for this development is the abundance of water.
The formation of the lake goes far back in time, probably 80 years ago. Sometime in the early decades of the 1900s, an earthquake hit Negros Island, and one of its effects was the substantial damming by rocks of a major tributary of the Siaton River at an elevation of ca 500 meters above sea level. The result was the creation of the present Balanan Lake (ca < 100 ha) at the upper portion of the tributary.
The late Gov. Emilio Macias II should be given the credit for developing the lake area into what it is now: a tourist destination.
Through his able and visionary leadership, a road to the lake and several infrastructures to provide for visitors’ needs have been built. It is hoped that the leaders of Negros Oriental will sustain his effort.
Now Balanan Lake is visited by people from many parts of the country and the world. Visitors are given the opportunity of enjoying the luxury of breathing unpolluted fresh air, swimming, and boating in the clean water of the lake.
But more importantly, the Lake Balanan story is a demonstration of the need to protect the natural environment to enrich the quality of human life.