What are Models?

Models are abstract representations of the real world that are useful for thinking, forecasting, and decision-making. We use informal models to help us with many everyday decisions.

For instance, a canoeist usually has in mind a model of how to respond if the canoe capsizes. This mind model is based mainly on experience, but also perhaps on reading and listening to others. This model includes knowledge of the canoe’s passengers (age, size, experience, ability) and cargo (weight, value), and the situation (whitewater vs. flatwater, weather, distance from campsite or vehicle).

A model that most of us are familiar with is a map. While there is very little physical correspondence between a map and the forest it represents, maps are essential for making most decisions related to planning forestry activities.

Management choices are often based on choosing among various predicted outcomes, which themselves are based on premises and assumptions. Modeling helps to clarify a problem by forcing us to recognize the assumptions on which predicted outcomes are based. Often, the process of modeling reveals vagueness and gaps in our understanding.

Because they help us “capture” our knowledge about a system, state our assumptions clearly, and explore options quickly and easily, models are very useful in forest analysis and planning.

Forest Analysis

Forest analysis is a process for exploring the ways in which different forest management strategies (including timber harvesting levels) are likely to affect forest structure, timber production, and the amount of other products and resources (e.g., habitat) available in the future. Often a computer model is used to forecast the development of the forest, given specific schedules (what, where, when) of management activities. Forest analysis supports many types of planning in British Columbia, including land-use planning, forest ecosystem and management planning, the determination of allowable annual cut, and the development of habitat management strategies for species at risk.

What Kinds of Models are used in Forest Analysis and Planning?

Many different kinds of models can be used in forest analysis and planning. They differ in:

• whether they represent individual forest stands or cutblocks (so-called spatial, spatially explicit or geo-referenced models), or lump together all stands of the same type (so-called aspatial, or stratified models)
   
• how they project growth and harvesting of trees into the future—e.g., one decade after another, simulating how the forest would develop and how people would select stands for harvesting (simulation); or all decades simultaneously to determine the best time to cut, plant, or otherwise treat certain stand types (optimization)
   
• the amount of detail included—models should have just enough detail to represent the problem of interest. Too much detail obscures the important parts of the problem; too little detail makes the model seem “unrealistic.”

Many models are available. Computer models commonly used for forest analysis in BC include FS-SIM (usually used in aspatial mode), Woodstock (aspatial), Woodstock-Stanley (a spatially explicit version of Woodstock), SELES (spatially explicit landscape model), and Woodlot (aspatial, developed especially for use by woodlot operators in BC). In some cases, a simple spreadsheet model is adequate.

What Kinds of Models are Suitable for Community Forestry?

The suitability of a model depends on the questions you need to answer (based on your management objectives), the data you have to work with, your modeling expertise, and the time and budget available. If your inventory data is old or unreliable, or the area involved is very small, it is probably not worthwhile investing in a very detailed model.

Communities interested in maintaining wildlife habitat, cultural sites, recreational trails, and opportunities for harvesting timber and non-timber forest products may need a spatial model that can represent how the forest will grow under different forest management strategies.

Communities with specific employment and financial objectives need a model that can incorporate information about the economics of forest harvesting, manufacturing, and trade that can be used to predict levels of employment and profit from different approaches to forest management.

Communities interested in modeling the effects of ecosystem-based management may need a model that can track and manage ecological representation at multiple scales and across neighboring management units.

Choosing a Model

In selecting the modeling approach to suit your needs, the first step is to clarify the questions you want answered, the information and expertise you have available, and the time and budget available. Then consult with someone who has experience in forest analysis.

Cortex Consultants Inc. has extensive experience building and implementing forest models for a wide range of clients in British Columbia. Some examples:

• a spreadsheet-based forest enterprise model to explore the economic and social implications of various forest development scenarios (Hul’qumi’num Treaty Group)
   
• aspatial and spatial models of private lands with sufficient financial and spatial detail to guide planning at strategic and operational levels (TimberWest)
   
• linked aspatial forest management models with spatial owl habitat and population models to evaluate recovery strategies (Canadian Spotted Owl Recovery Team)
   
• a spatially explicit individual-based model of caribou demography and movement behaviour in response to habitat preferences and predation risk (Northern Caribou Recovery Implementation Group).

If you would like to discuss your modeling and planning needs with us, please call Doug Williams at 250.360.1492.