Silviculture Worksheet¶
Optional Worksheet
If a plunit has area at any point across the first period of the model then by convention it is part of the 'Current Rotation' of forest. When current rotation area is clearfelled and replanted it becomes part of the 'Future Rotation' of forest. Plunits that are part of the future rotation have an age that is less than the period of the model in which they exist.
The Silviculture worksheet defines the allowable options for transferring area between plunits that are part of the current rotation only. The Silviculture worksheet has no effect on any plunit area that is part of the future rotation. That is, constraints on the Silviculture worksheet will only ever be able to apply to planning units with an area defined on the Plunits worksheet and which therefore exist at the very outset of the optimisation model.
Note
The Silviculture and the Replanting worksheets are often misinterpreted. A simple rule of thumb is to remember that the Replanting worksheet considers the regime options for the forest estate as it transitions from its current rotation into all of its future rotations of forest. The Silviculture worksheet is confined to area transfer between regimes for current rotation plunits only. The Silviculture worksheet has no effect on any plunits that are part of the future rotation of forest. Only the Replanting worksheet defines the possible regime options that future rotations of forest can be established into and will follow.
Example¶
The Silviculture worksheet is based around the use of a Group/Attribute 'plunit filter' to define the 'Origin' plunits that will be the source of the forest area that may transfer to the 'Destination' plunits defined by the constraint.
Silviculture transfers will only apply to the area age classes that fall within the minimum and maximum ages of each constraint.
The constraints on the Silviculture worksheet are ultimately distilled back to the underlying plunits to which they refer. This means that the plunits need to exist on the Plunits worksheet if they are to be valid destinations into which area can be transferred. Any plunit can be a destination for transferred area regardless of whether it has an existing area age class defined on the Plunits worksheet or not.
The Silviculture worksheet is commonly used to define alternative production thinning regimes for the planning units. Alternative production thinning regimes can consist of a different number of thinning events, different timings of thinning events and/or the transfer of area from a commercial thinning regime to a non-commercial thinning regime to avoid the production of unsaleable log volumes within the estate.
The Management worksheet is similar to the Silviculture worksheet inasmuch as it involves the transfer of area from one current rotation plunit to another, however the Management worksheet does not define the destination plunits that will accept an area transfer. Instead it makes automatic copies of the origin plunits and accepts the transferred area keeping all the attributes of the original plunit intact apart from any core data groups where the user has defined an alternative.
The Silviculture worksheet on the other hand is less constrained so the user can setup transfers between plunits irrespective of the plunit's attributes. For example it is possible to transfer current rotation area from a radiata pine plunit to a eucalypt plunit. This may seem counter intuitive, but the functionality is powerful and can be used to model unusual scenarios within the estate, e.g. fire damage.
Column Definitions¶
Users should not insert columns before Column 'B' and should not insert rows before Row '4'. The ordinal position of the data columns must remain.
| Group | Column | Description |
|---|---|---|
| Origin Group | B | This a Group from the Plunits worksheet that has been defined with attributes assigned to one or more plunits. |
| Origin Attribute | C | This is a valid Attribute of the Origin Group above, and this Attribute selects the plunits that will be the origin of any area that is transferred to the destination plunits defined by the row. |
| Min | D | This is the minimum age of the age class range from which area can be transferred from the origin plunits to the destination plunits defined by the row. |
| Max | E | This is the maximum age of the age class range from which area can be transferred from the origin plunits to the destination plunits defined by the row. |
| Type | F | This is either a value of 'Optional ' or 'Mandatory'. It is convention to set this to 'Optional' so the optimiser can decide to take the transfer or not. A setting of 'Mandatory' is used when it has been predetermined to force the transfer of area from one plunit to another for some reason. Normally a mandatory transfer would be achieved by updating the standard forest description so that the area transfer is visible to all users of the forest description. |
| Destination Group | G | This a Group from the Plunits worksheet that has been defined with attributes assigned to one or more plunits. |
| Destination Attribute | H | This is a valid Attribute of the Destination Group above, and this Attribute selects the plunits that will be the recipient of any area transferred from the origin plunits defined by the row. |
Note
Throughout the forest description, groups 'Start' and 'End' always infer and apply to a period, while groups 'Min' and 'Max' always infer and apply to an age.