(1) Forest land productivity value is subject to change as a result of reappraisal, a land use change, or through acreage changes incidental to updates from the Geographic Information System or fluctuations in agricultural land use due to typical farming practices. The department must phase in value increases as provided in 15-7-111, MCA.

(2) Before the department can apply any annual phase-in value, the department first determines the difference between the value before reappraisal (VBR) and the full reappraisal value.

(3) If the forest land's productivity value changes as a result of:

(a) reappraisal, the department will use the full reappraisal value from the previous reappraisal cycle as the VBR;

(b) a land use change, the VBR is calculated as if the new forest land acres had existed before reappraisal; or

(c) acreage changes due to department updates from the Geographic Information System, or due to incidental fluctuations in agricultural land use due to typical farming practices, the department will use the forest land value from the last year of the previous valuation cycle as the VBR.

(4) The phase-in value calculations for each year of the reappraisal cycle are as follows:

(a) Year 1 phase-in value = VBR + (change in value x .1666);

(b) Year 2 phase-in value = VBR + (change in value x .3332);

(c) Year 3 phase-in value = VBR + (change in value x .4998);

(d) Year 4 phase-in value = VBR + (change in value x .6664);

(e) Year 5 phase-in value = VBR + (change in value x .8330); and

(f) Year 6 phase-in value VBR + (change in value x 1.000).

(5) For forest land that deceases in value due to reappraisal, the lower value will be fully implemented immediately and will not be phased in.