Sustainability Report 2004

Environmental aspects

The Watershed Project

In 2004, we completed 11 years of work on the Watershed Project, which focuses on key environmental and forest production issues and has contributed not only to the management of Aracruz’s plantations but also to the scientific community and public policies in general. The project involves integrated studies of water resources, soils and biodiversity, and is being developed in partnership with institutions in Brazil and abroad.

Most of the eucalyptus plantations in the watershed were harvested during the year, and two seminars were held to enable broad discussion and consolidate the results obtained so far. Some of the main results are presented on the next page.

Hydrological cycle

  • The use of water by eucalyptus plantations was found to be similar to native forests (around 1,100 mm/year),including the water absorbed by plants and returning to the atmosphere via transpiration,soil evaporation and rainfall interception by the forest canopy.
  • The efficiency of eucalyptus in the use of water was proven, confirming their capacity to produce more biomass per volume of water consumed when compared with other tree species.
  • Water use is concentrated in the first 1.5 meters of soil depth, where most of the roots are found.
  • No significant effect was discovered in terms of harvesting plantations on the surface run-off of water,a fact explained by the high water-retaining capacity of the soils.

The figure below shows the relationship between the input of water via precipitation (P)and the output via evapo-transpiration (ET)for each year over the last nine years.The eucalyptus plantations showed an ET/P rate of 0.79 compared with 0.85 for native forest, where the value 1.0 signifies equilibrium between water input and output in the basin.The results indicate that the average annual water consumption in the eucalyptus plantations was 1,131 mm, compared with 1,214 mm in native forests,while the average rainfall over the years of the study was 1,211 mm,indicating an excellent hydrological balance.

Water balance in the watershed

chart

Physiology

Various examples of genotype planted on Company property were analyzed, identifying their physiological differences and behaviors, allowing an improved adaptation to use in different conditions.

Soils

The soil management practiced in the Watershed Project is based on low environmental impact and has acted as a prototype model for the Company ’s other areas.Restricting soil preparation to the line of planting was proven to be important in maintaining the system ’s set of nutrients and organic matter.This is an indispensable condition for avoiding soil depletion.The current system of cultivation was found to be sustainable in terms of soil fertility due to the volume of debris left in the area combined with the corrective fertilizers applied during each new cycle.

Biodiversity

The bird studies showed that the eucalyptus plantations and their understory vegetation act as a corridor for biodiversity between native forest fragments.They also possess great importance as a source of resources for these populations.A total of 205 bird species have been identified in the watershed over the 11 years of study,along with an assessment of the effects of forest cultivation practices on these populations.

Research on the flora of the eucalyptus understory carried out at the end of two rotations revealed over 120 species growing in this vegetation.

Another campaign for monitoring the plant ecology and dynamic of native forest growth was undertaken in 2004.The results showed the ecological stability and conservation of these Atlantic Forest fragments.

Integration

The integration of various areas studied in the Watershed Project is being evaluated using a forestry process-based model to know the factors that influence tree growth. This model was fed with data obtained from the Watershed Project and is being applied to other Company areas in order to estimate and quantify the effects of climate and adopted management practices on plantation growth.

Aracruz has released all the information generated by the Watershed Project to the scientific community, teaching institutions and the general public. The Company also welcomes on-site visits and discussion of results with the researchers involved in the project. For further information, visit the site: www.aracruz.com.br/web/en/ambiente/.