Planning Horizon

The planning horizon is the number of years that the simulation covers. The planning horizon is divided into periods. The number and width of each period is defined in the Patchworks input file. Planning periods are typically equal width, but they don't have to be. It is possible to have different width planning periods in order to have higher resolution in the time periods that we feel are more important. The scheduling of the treatments is always annual, but the setting of targets and reporting of outcomes is always periodic. The planning horizon in the sample dataset is 200 years, made up of 40 five-year periods.

Large numbers of planning periods will increase the amount of memory required to run the model, and will also increase the amount of time needed to achieve stable solutions. Although the upper size limit for the number of planning periods will vary with other factors (such as the number of candidate harvest blocks, number and type of accounts, and complexity of silvicultural treatments and responses). Patchworks has been designed to operate with at least several rotations of treatments in order to ensure sustainability. We have found that the 5-year planning periods tend to be appropriate trade-off between temporal resolution and amount of detail. A 200-year planning horizon can be represented with 40 5-year planning periods, which is still a comfortable number to deal with in reports and other output. On the other hand, 10-year planning periods may allow too much within-period variability, and 1-year planning periods would generate an overwhelming amount of detail and longer running times.