(2) Land classified as open space land shall have an assessed value for the tax year equal to the lesser of the land’s maximum assessed value or the land’s open space value determined under subsection (5) of this section.

(3) The land’s maximum assessed value shall equal 103 percent of the land’s assessed value for the previous tax year or 100 percent of the land’s maximum assessed value for the previous tax year, whichever is greater.

(4)(a) For the first tax year for which the land is classified as open space land, the land shall have a maximum assessed value equal to the land’s open space value determined under subsection (5) of this section multiplied by the ratio of the total maximum assessed value of all open space land within the county over the total open space value of all open space land in the county.

(b) If there is an insufficient amount of land classified as open space land in a county to permit a statistically reliable ratio to be determined under paragraph (a) of this subsection, the statewide totals of maximum assessed value of open space land and open space value shall be used in determining the ratio.

(c) The Department of Revenue shall prescribe rules setting forth the minimum amount of open space land in a county needed to establish a statistically reliable ratio.

(5) The open space value of land classified as such under ORS 308A.300 to 308A.330 shall be the land’s real market value under ORS 308.205:

(a) Assuming the highest and best use of the land to be the current open space use, such as park, sanctuary or golf course. The assessor shall not consider alternative uses to which the land might be put.

(b) Valuing the improvements on the land, if any, as required by ORS 308.205. [Formerly 308.765; 2003 c.169 §3]