The impact of environmental constraints on short term harvesting: Use of planning tools and mathematical models

Both in New Zealand and Chile there exist important forest industries based mostly on pine plantations. The management of harvesting requires a series of activities such as building access roads, harvesting with skidders on flat terrain and cable logging for steep terrain, transportation from forest origins to destinations, such as a port, pulp plant and sawmills. These harvesting activities imply some potentially harmful environmental impacts such as water sedimentation, erosion and loss of scenic beauty. This has led to the proposal of several mitigating actions, such as creating riparian strips along rivers, avoiding the use of heavy machinery on fragile soils and minimizing road building. The degree of implementation of these mitigating actions differs in Chile and New Zealand. In New Zealand, the 1991 Resource Management Act regulated the implementation of environmental protection measures. In Chile a series of such measures have been implemented, but a set of definite regulations has not been defined yet and there is a need to develop an economic evaluation of the implementation of environmental measures in terms of reduced timber production and high harvesting costs, together with the benefits of the environment. To support decisions at tactical and operational levels, mathematical models have been developed both in Chile and New Zealand and are being used successfully by the timber industries. These models can be modified to consider diverse environmental protection measures. We analyze the implementation of these modifications and how the new models can help evaluate the economic impact of the protection measures. We show some preliminary results.