WOODLOT for Windows 2.1 - Reference Manual

12.6 Constraints Turn on constraints by clicking on the desired radio buttons. Constraints apply to the entire woodlot. Choose between: No Constraints, Net Down (Area), Height and/or Age If you calculate the Harvest Rate with the Automatic check box clicked on, then the constraints will apply and the harvest rate may be reduced. If you force a cut, the Standing Volume/Year graph will display vertical colours for periods when the constraint cannot be met. The following graph, prepared in the GRAPH function (and is the same graph as displayed in the Calculations screen) shows periods when various height and age constraints will not be met. These periods are reported as "errors", though this simply means that the cut cannot be achieved through this period. If you calculate the Harvest Rate with the Automatic check box clicked off (i.e. manually), the constraints can be overridden. If this occurs, messages will be displayed in the Harvest Parameters Not Met screen to the right if harvest parameters cannot be met. Colored vertical bars will appear in the Standing Volume/Time graph at the times where height and/or age constraints cannot be met: Vertical red bars refer to a height constraint not being met in the period shown Vertical yellow bars refer to an age constraint not being met in the period shown 12.6.1 No Constraints If you have no constraints, leave the No Constraints radio button selected. This will assume that all stands will be harvested with no additional constraints. This is the default setting for WOODLOT. 12.6.2 Net Down(Area) Use this feature if you do not know the height or age constraints, but have a general netdown value you would like to use. This is an area specific constraint (i.e., not temporal). The net operable area of all polygons in the woodlot will be reduced by this amount. 12.6.3 Height and/or Age Use this feature if you know the forest cover constraints for the woodlot. You may use height, age, or both constraints as follows: Height constraint: at least U% of the woodlot must be greater than V m tall. This might be used for hydrology or greenup constraints. Age constraint: at least X% of the woodlot must be older that Y years of age. This might be used for temporal (floating resource constraint over time) constraints, such as VQO, wildlife or biodiversity.

by Enfor Consultants Ltd. Last Updated March 1999