The type of thinning limit, how fertilizer rates are defined, and thinning specs are entered on this tab. Thinning treatments cannot be simulated for hardwood stands.
Mid-rotation thinning limits can be specified in terms of residual basal area or residual trees/acre. Fertilizer rates can be entered in terms of product (lbs of urea and/or DAP) or elements (lbs N and/or P). The minimum and maximum thin age defines a thinning “window” in which a thin is simulated for each increment of age. The thinning limit in terms of the type of thinning limit (described above) is used for each thin in the thinning window. When Fert at Thin1 or Fert at Thin2 is checked, fertilizer rates in terms of product or elements (described above) may be entered. Checking Include Thin/NoFert scenarios will include thinned but unfertilized scenarios when Fert at Thin1 or Fert at Thin2 are checked.
The first thin is a combination of row and selection methods while the second thin is selection only. The first thin uses selection only when Previously Thinned is checked; only 1 thinning may be simulated in these cases. Row thinning is not implemented unless basal area at time of thinning is greater than 1.25 times the specified residual basal area minus 5 for basal area thins or 1.25 times the specified residual trees/acre minus 25 for TPA thins. All possible combinations of first and second thins are simulated unless they are less than 5 years apart. In addition, a no thin scenario is always simulated.
The following thinning scenarios (with and without fertilization at the first thin only) will be implemented for the settings shown above:
No thinning
12 only; 12+17; 12+18; 12+19; 12+20; 12+21; 12+22 (thin at 16 is less than 5 years after the first thin)
13 only; 13+18; 13+19; 13+20; 13+21; 13+22
14 only; 14+19; 14+20; 14+21; 14+22
15 only; 15+20; 15+21; 15+22
16 only; 16+21; 16+22
17 only; 17+22
18 only