Evaluación de transectos de regeneración establecidos en parcelas experimentales

Regeneration of commercial tree species after different silvicultural treatments in a Bolivian moist tropical forest

Many commercial tree species in Bolivia have too little regeneration. It seems that many of these species need disturbances such as gaps or clear cuts, skid-trails, log landings or other soil scarification in order to have a proper amount of regeneration. In a moist tropical forest, four treatments were carried out, the first ‘Undisturbed’ treatment functions as a control treatment, and the ‘Normal’, ‘Improved’, and ‘Intensive’ treatments each have an increasing set of silvicultural treatments, respectively.

The question was in which of these treatments the highest density and growth rates were observed, and which factors contributed to this growth. Most plots have been measured three times, in a period of approximately four years, with the last measurement at the end of 2004 (N=11,711 plants).

A large variance between different measuring blocks was observed. The Undisturbed treatment showed the highest densities, but if harvesting was carried out, the Intensive treatment numerically showed the highest densities. For the growth rates, all treatments differed significantly from each other, in an order such that a higher disturbance rate led to higher growth rates. It seemed that the factor of light (crown position index), explained 26% of the total growth rates (total R Square = 0,37), and was therefore the largest explanatory factor. The Intensive treatment had the advantage of highest densities and growth increments, which allows for increased harvest intensity.