The criteria that the Texas A&M Forest Service uses in determining SMZ upon request from a chief appraiser or taxing unit is set out as follows.
  (1) SMZ includes forested buffers adjacent to streams or bodies of water, including intermittent and perennial streams, river, lake, slough, pond, creek, reservoir, watershed, or wetland (ephemeral streams are excluded).
  (2) The minimum width of an SMZ on each side and above the head of streams or adjacent to bodies of water should be 50 feet from each bank (however, with sufficient evidence shown, the width can be extended to no more than 200 feet depending on the slope, soil, cover type, and proximity to municipal water supply).
  (3) Total SMZ width includes average stream channel width plus buffer width.
  (4) If the SMZ's boundaries are not self-evident (e.g., clear-cut and young plantation may indicate a self-evident boundary) and not at a uniform width, the boundaries must be marked with paint or signs. Boundary marks can be no further than 100 feet apart.
  (5) Newly established SMZ's must have trees average 10 years of age or more with a minimum of 300 well-spaced trees per acre, or an average 50 square feet per acre of basal area in trees evenly distributed within the zone.
  (6) A management plan must be provided addressing best management practices for the SMZ consistent with the management plan for the silvicultural nonpoint source pollution management program developed by the Texas State Soil and Water Conservation Board. These guidelines are available from the Texas A&M Forest Service or Texas Forestry Association. The plan must address harvest restrictions, as prescribed in paragraph (7) of this subsection. The landowner must comply with the parts of the management plan that relates to the zone in order to qualify the land as a SMZ.
  (7) Harvesting is restricted to the extent that a minimum of 50 square feet per acre, on average, of residual basal area should be retained in trees evenly distributed within SMZ.

Source Note: The provisions of this §215.13 adopted to be effective January 30, 2000, 25 TexReg 378; amended to be effective February 15, 2015, 40 TexReg 595