(1) The forest practice of clearcutting is prohibited in the SMZ unless approved by the department under a site-specific alternative practice.

(2) In order to provide large woody debris, stream shading, water filtering effects, and to protect stream channels and banks, merchantable and submerchantable trees must be retained in the first 50 feet of the SMZ beyond the ordinary high water mark and in the entire SMZ where the SMZ is extended for wetlands under ARM 36.11.302(2) (a) , on each side of streams, and along lakes and other bodies of water as follows:

(a) On each side of class 1 stream segments and lakes retain 50% of the trees greater than or equal to eight inches dbh, or ten trees greater than or equal to eight inches dbh in each 100 lineal feet of the SMZ, whichever is greater.

(i) If less than ten trees greater than or equal to eight inches dbh are present in any 100 lineal-foot segment of the SMZ, then a minimum of ten trees of the largest diameter available must be retained in that segment;

(ii) Trees retained must be representative of the species and size of trees in the preharvest stand; and

(iii) Shrubs and submerchantable trees must be protected and retained in the entire SMZ to the fullest extent possible when conducting forest practices in the SMZ.

(b) On each side of class 2 stream segments retain 50% of the trees greater than or equal to eight inches dbh, or five trees greater than or equal to eight inches dbh in each 100 lineal feet of the SMZ, whichever is greater.

(i) If less than five trees greater than or equal to eight inches dbh are present in any 100 lineal-foot segment of the SMZ, then a minimum of five trees of the largest diameter available must be retained in that segment;

(ii) Trees retained must be representative of the species and size of trees in the preharvest stand; and

(iii) Shrubs and submerchantable trees must be protected and retained in the entire SMZ to the fullest extent possible when conducting forest practices in the SMZ.

(c) On each side of class 3 stream segments and other bodies of water, shrubs and submerchantable trees must be protected and retained in the entire SMZ to the fullest extent possible when conducting forest practices in the SMZ.

(3) Hardwood trees and snags meeting diameter standards of (2) may be counted toward retention tree requirements in the same approximate proportion as their occurrence in the stand prior to commencement of forest practices.

(4) Trees retained pursuant to this rule must be distributed within the SMZ as guided by the following criteria:

(a) favor bank-edge trees;

(b) favor trees leaning toward the stream and those that cannot be felled without falling into the stream;

(c) where the SMZ is greater than 50 feet wide and harvesting will result in the minimum stocking of trees required to be retained under (2) (a) and (b) , concentrate retained trees within 50 feet of the stream;

(d) all trees that have fallen through natural processes, across or in a class 1 or 2 stream, must be retained, unless removal of such trees is conducted pursuant to ARM 36.11.304(6) , is approved as a site-specific alternative practice, and is conducted consistently with other applicable federal and state laws and regulations.

(5) Trees retained pursuant to this rule may be salvaged only under the following conditions:

(a) trees to be harvested meet the definition of salvage found at ARM 36.11.312; and

(b) the minimum tree retention requirements of (2) are met by standing live trees, or by dead or fallen trees where sufficient standing live trees are not available.

(6) All practices which deviate from the tree-distribution criteria provided in (2) and (4) require approval as site-specific alternative practices.