Case Study 2

"Prescribed Fire" on page 114.

PRESCRIBED FIRE Using fire in forest management sounds contradictory. Prescribed fire, however, is an important tool for foresters, and a recent article describes how decision analysis is used to decide when, where, and what to burn. In one example, a number of areas in the TahoeNational Forest in California had been logged and were being prepared for replanting. Preparation included prescribed burning, and two possible treatments were available: burning the slash as it lay on the ground, or"yarding of unmerchantable material"(YUM) prior to burning. The latter treatment involves using heavy equipment to pile the slash. YUM reduces the difficulty of controlling the burn but costs an additional $100 per acre. In deciding between the two treatments, two uncertainties were considered critical. The first was how the fire would behave under each scenario. For example, the fire could be fully successful, problems could arise which could be controlled eventually, or the fire could escape, entailing considerable losses. Second, if problems develop, they could result in high, low, or medium costs. Question 1. What do you think the U.S. Forest Service'sobjectives should be in this decision? In the article, only one objective was considered, minimizing cost (including costs associated with an escaped fire and the damage it might do). Do you think this is a reasonable criterion for the Forrest Service to use? Why or why not? Question 2. Develop an influence diagram and a decision tree using PrecisionTree for this situation. What roles do the two diagrams play in helping to understand and communicate the structure of this decision?