A limitation of conventional permanent plots is their small size-usually one hectare. For research purposes of the impacts of the use, both of fauna and flora, one hectare does not allow to collect relevant information. Therefore, in order to assess the impact of the use of forest dynamics and biodiversity, as well as to generate information on the most appropriate silvicultural treatments for the country, the BOLFOR project, in collaboration with Bolivian institutions and international organizations, began in 2000 the execution of a Long-term Silvicultural Research Project (PISLP). The responsibility to continue with this research project was transferred to IBIF towards the end of 2003.
The PISLP consists of installing repeated experimental plots in different types of tropical forest in Bolivia to determine management practices appropriate to each type of forest.
So far, there are three blocks of plots in the subhumid forest (Guarayos zone), 1 block in a subhumid forest in the Bajo Paraguá (TCO of the Bajo Paraguá Indigenous Plant), two blocks in a dry forest (in the private property INPA) and a block in a very humid Amazon forest (in the SAGUSA forest concession). Each block contains an untapped control plot, a plot harvested using traditional methods (use of reduced impact with cutting of vines prior to harvesting) (Normal), a plot of moderate forestry (marking and release of future crop trees) and a intensive forestry plot (harder use, more intensive release treatments and soil scarification in clearings to induce regeneration). The treatments that were applied in the experimental plots represent alternatives of intensity of use and silvicultural systems. The detail of these treatments is described as follows:
Treatment Witness.- The plots of this treatment have not been exploited, although some vines were cut in the trees that could be used during the census phase.
(Normal Use) .- This treatment receives use according to the current extraction system of the company. This system includes: (a) road planning and utilization based on a commercial census of harvestable and remaining trees, (b) use of trees that exceed the minimum cutting diameter (DMC), generally 50 cm of DAP, (c) 20 % of commercial trees greater than the diameter limit are left as seedbeds and as a safety factor. (d) Cutting of vines from commercial trees before harvesting, and (e) cutting directed.
(Use with Low Silviculture) .- The procedure of this treatment has received the operations described for the normal treatment, and additionally the following treatments were applied: (a) marked before harvesting trees of future harvest (AFC) of the species which are currently extracted by the company (Annex 1) (b) Cut of all vines located in the shaft or the AFC cup and (c) release of AFC from non-commercial competitors by ringing.
(Harvesting with High Silviculture) .- This treatment received all the operations of the improved treatment, and additionally the following treatments were applied: (a) Additional marking of AFC of potentially commercial species, (b) cutting of vines and release of AFC of species potentially commercial, (c) double intensity of exploitation that includes the extraction of species that are currently not harvested by the company, but that are potential species, (d) improvement of stands that include banding of individuals of non-commercial tree species with DAP greater than 40 cm, except for important species for fauna (e) Mechanized scarification of the ground in clearings of use using “skidder”, at the moment of the extraction of the trunks.