SMA: Managerial Data

Elements

Thinning definition

The optimization requires that the number of thinnings and the number of thinning points be specified. Each number of thinnings forms a different optimization problem with different variables to be optimized. Reasonable values are 1-3. If a smaller number of thinnings provides a higher objective function value, the optimization may drive thinning percentages to zero for unwanted thinnings.

The thinning points define the accuracy of specifying thinning rates for trees with different diameters. Reasonable values are 1-5.

Planting density

The underlying stand simulator features four species. The user can specify for each species independently whether planting density is optimized. Planted trees are added to whatever seedlings may occur as a result of natural regeneration or an initial tree list. Establishment costs are adjusted according to planting density.

Specify computers

The button brings up this window for choosing computers.

Round wood prices

The wood prices refer to prices for wood delivered to road side in the forest, per unit volume (FIM/cu.m.). The default values are recorded in the file sima.laj (at the end), located in ../sima directory.

Bare land value

The bare land value is used when computing discounted net revenues of stand management. It is used for approximating the value of future rotations, required for computing the soil expectation value. The bare land value depends on the interest rate. Reasonable values for Finnish conditions are given below:

Interest rate, %    Bare land value, FIM/ha

       0                1 000  (Corresponds to average annual cash flow)
       1               70 000
       2               25 000
       3               10 000
       4                3 000

Interest rate

Discounting is based on the interest rate, here defined as a real, tax tree rate of interest. The present value criterion implies, strictly speaking, that unlimited amounts of money are available and can be invested at the rate given as interest rate. Interest rates greater than 4 % may lead to negative soil expectation values and disrupt optimization.