Planning Forest Operations: A Rule-Based Spatial DSS Built with ModelBuilder

By Daniele Lubello, University of Padova, Italy

Forestry management in Italy faces many challenges. Most forestland is privately held. Steep terrain and lack of infrastructure make access to forestland difficult. Also, highly regulated protected areas limit the volume of timber that can be harvested per surface unit. These factors drive harvest costs up and make Italy’s timber less competitive in the market. Improving operational efficiency through better management is one way that the Italian forest industry can enhance its competitive position.

Now, a GIS-based model design provides a decision support system (DSS) for forest managers. It models wood production and hydraulic and soil protection in steep Alpine areas. It also includes biodiversity, conservation, and tourism factors. For example, managers can analyze ways that the density and size of standing trees influence skidding operations. They can create forest plans that include environmental and stand factors and determine the best methods that cause the least amount of soil compaction damage for a given terrain.

Data used to define the skidding system includes soil and rain data, shown here,
as well as forest road networks and elevation data layers.
This is called the Forest Operation Planning (FOpP) model. It defines the type of skidding process that should be used based on forest area criteria. It then calculates where that system would best work to reduce operational costs and increase the value of wood.

The application designer chose ArcGIS ModelBuilder to build the FOpP model because it is a powerful GIS design tool and does not require knowledge of any programming language. The software allows the user to create a model in a step-by-step fashion. It checks for errors and ensures that all data is in the same projection. For complicated models, outputs can be stored in a geodatabase.

The designer built the model to consider technical limits of a skidding process, determine feasible areas for each selected skidding system, and generate feasibility maps. Output maps distinguish the skidding direction. For example, the model assesses the cable system method by verifying that the average inclination from each cell to the nearest road is sufficient for the system to operate.

The map of the wood supply basin between Italy and Slovenia shows supply cost differences.
Other outputs are grid maps and database tables that contain statistics for the forest stand. The model calculates minimum, maximum, average, and total costs based on the yield distribution and the type of skidding system used. It can also estimate how much wood will be skidded to each forest road section and calculate the average cost of this process.

Forest planners can use these results to determine the cost and effect of building and maintaining a new road for transporting wood. The results of the FOpP model provide a good starting point for the analysis of the forestry-wood chain. For instance, by adding felling and other administrative costs, it is possible to estimate total operational costs and compare them with wood market prices. In addition, a forest manager can determine whether operations will be profitable or evaluate the effect of silvicultural management on timber yield and total harvesting costs. The GIS model is also valuable for estimating transportation costs and providing useful logistical information.

ESRI Forestry GIS Journal, Summer 2009
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