As used in this chapter:
(a)
“Basal area per acre” means the sum of the cross-sectional areas at breast height of the tree stems of commercial species per acre.
(b)
“Countable tree” means a tree that can be used in calculating the degree of stocking under the following criteria:
(1)
The tree must be in place at least two growing seasons.
(2)
The tree must be live and healthy.
(3)
The tree must have at least one-third of its length in live crown, except in pure stands of Douglas fir the tree must have at least one-fourth of its length in live crown.
(4)
The tree must be a commercial species from a local seed source or a seed source which the registered professional forester determines will produce commercial trees physiologically suited for the area involved.
(c)
“Stocking” means a measure of the degree to which space is occupied by well-distributed countable trees.
(d)
“Site classification” means the classification of productive potential of timberland into one of five classes by board regulation, consistent with normally accepted forestry practices. Site I shall denote sites of highest productivity, site II and site III shall denote sites of intermediate productivity potential, and site IV and site V shall denote sites of lowest productivity potential.
(e)
“Fuel break” means a strip of modified fuel to provide a line from which to work in the control of fire.
(f)
“Stream” means a natural watercourse as designated by a solid line or dash and three dots symbol shown on the largest scale United States Geological Survey map most recently published.