Current through Register Vol. 6, March 22, 2024
(1) The department shall establish an
equipment restriction zone (ERZ) adjacent to the minimum width of the SMZ
required under ARM
36.11.302
when forest management activities are proposed on sites with high erosion
risk.
(2) The department shall
determine the presence of high erosion risk from:
(a) established soil surveys;
(b) existing inventories; or
(c) site-specific field evaluations.
(3) When the department
proposes forest management activities on sites determined to have high erosion
risk:
(a) the department shall establish an
ERZ that when combined with the SMZ has a minimum of 100 feet when activities
are located on slopes greater than 25 percent but less than 35 percent;
(b) the department shall establish
an ERZ that when combined with the SMZ has a minimum of 150 feet when
activities are located on slopes greater than or equal to 35 percent, but less
than 50 percent;
(c) the
department shall establish an ERZ that when combined with the SMZ has a minimum
of 200 feet when forest management activities are located on slopes greater
than or equal to 50 percent; and
(d) the department may modify and shorten ERZ
widths established for high erosion risk when topographic breaks, existing
roads or other factors are present that reduce erosion risk and provide
suitable sediment delivery filtration. Modified or shortened ERZs must still
meet the minimum width of the SMZ required under ARM
36.11.302
and riparian management zone (RMZ) required under ARM 36.11.425.
(4) The following restrictions
apply to forest management activities conducted within an ERZ established for
high erosion risk:
(a) The department shall
limit new road construction within an ERZ to situations in which:
(i) a stream crossing is required;
(ii) potential impacts can be adequately
mitigated; or
(iii) alternative
locations pose higher risk of resource impacts.
(b) The department shall restrict
ground-based equipment operations within the ERZ.
(i) The department shall not allow the
operation of wheeled or tracked equipment within an ERZ when it is located on
slopes greater than 35 percent;
(ii) The department shall not allow the
operation of wheeled or tracked equipment within an ERZ when it is located on
slopes less than 35 percent, unless the operation can be conducted without
causing excessive compaction, displacement, or erosion of the soil;
(iii) The department may allow the use of
wheeled or tracked equipment inside of that portion of an SMZ or ERZ when
operated from an established road on the side of the road away from the stream
pursuant to ARM
36.11.304.
(c) The department
shall restrict cable yarding of logs within and across an ERZ to cable systems
and operations that do not cause excessive ground disturbance within the SMZ or
ERZ.
(5) The department
shall establish an RMZ which includes the minimum width of the SMZ required
under ARM 36.11.302, when timber harvests are proposed on sites adjacent to
fish bearing streams and lakes and on HCP covered lands adjacent to all Class I
streams or lakes, which will:
(a) have a
minimum width equal to the 100-year site index tree height;
(b) determine the 100-year site index tree
height at the project level by field sampling the age and height of several
site trees within the riparian stand and comparing those values to locally or
regionally develop site index curves;
(c) maintain a 50-foot wide buffer within
Class I 1 RMZs, which:
(i) will start at the
ordinary high-water mark and extend across the RMZ to a slope distance of 50
feet when measured perpendicular to the stream or lake; but
(ii) within the 50-foot wide no-harvest
buffer, it may be necessary to allow corridors associated with cable logging
systems to fully suspend logs across streams; and
(iii) in these situations, the minimum
corridor spacing will be 150 feet with no more than 15 percent of the 50-foot
wide no-harvest buffer affected;
(d) retain shrubs and sub-merchantable trees
to the fullest extent practicable, and a minimum of 50 percent of the trees
greater than or equal to 8 inches DBH for harvest within the remainder of the
RMZ;
(e) specify that multiple
harvest entries into a specific RMZ stand will only occur if:
(i) the existing RMZ stand is classified as a
medium to well-stocked, poletimber or saw timber size class; and
(ii) the proposed harvest meeting the minimum
retention tree requirements in ARM
36.11.305;
and
(f) extend SMZs to
include adjacent wetlands, where the normal SMZ boundary intercepts a wetland.
Retention tree requirements are the same as the requirements for the first 50
feet of SMZ.
(6)
The department will extend RMZs in situations where channel
migration is likely to influence riparian functions that are potentially
affected by timber harvests by:
(a)
establishing a Type 1 Channel Migration Zone (CMZ) within the flood prone area
of meandering valley bottom streams that are actively eroding and depositing
sediment through lateral migration of the stream channel, where:
(i) the portion of RMZ restricted to 50
percent retention on a Type 1 CMZ is extended to incorporate the entire flood
prone area;
(ii) the standard RMZ
harvest restrictions will be applied in the event that the width of the flood
prone area does not extend beyond the normal RMZ;
(iii) the 50-foot buffer will not be extended
on a Type 1 CMZ;
(b)
establishing a Type 2 CMZ within the flood prone area of unstable streams
exhibiting sudden erosion and deposition processes, where:
(i) on a Type 2 CMZ the normal 50-foot RMZ
buffer is extended to include the entire flood prone area plus an additional 50
feet within the RMZ;
(ii) no timber
harvest will occur within the entire flood prone width;
(iii) the delineation of the normal RMZ,
including the additional 50 foot buffer, will begin at the edge of the flood
prone width; and
(iv) examples of
sudden erosion and deposition process are:
(A) moderately contained stream channels with
evidence of recent sediment deposition in the flood prone area;
(B) alluvial fans; and
(C) debris flows or torrents.
(7) The
department shall retain all bank edge trees on timber harvests conducted
adjacent to streams.
(8)
Allowances for harvest within class I RMZs shall include:
(a) potential harvest of diseased and
insect-infested trees when an RMZ is being impacted by disease or insect
infestations; where:
(i) such harvest must
still meet the minimum retention tree requirements of ARM
36.11.305(2);
(ii) retained trees will include all
streambank and downed trees lying within the stream channel or embedded in the
stream bank;
(b) harvest
of diseased and insect infested trees from the remaining RMZ, outside of the
first 50 feet, may exceed those levels necessary to meet the normal 50 percent
retention requirement;
(c) the
salvage harvest of dead or downed trees which may exceed the normal 50 percent
retention requirement in that portion of the RMZ outside of the 50-foot buffer
in areas within an RMZ that have been subjected to windthrow and/or severe or
stand-replacement fires, but:
(i) such harvest
must still meet the minimum retention tree requirement of the SMZ
Law;
(ii) no salvage harvest of
fire-killed trees will occur within the 50-foot buffer;
(iii) downed trees lying within the stream
channel or embedded in the stream bank will be managed pursuant to ARM
36.11.305(4)(d);
(d) necessary
management of a portion of the total Class 1 RMZ acres of forested trust lands
using harvest prescriptions designed to meet the minimum retention tree
requirements under ARM
36.11.305
(SMZ Law), where:
(i) the RMZ stands target
to be managed in this manner will be those stand types where shade-tolerant
species exists, and regeneration or maintenance of shade-intolerant tree
species is necessary to achieve or maintain desired future stand types or
provide long-term riparian functions;
(ii) a 50-foot wide buffer will not be
required in these situations; and
(iii) tree retention will be based on the
number of trees within the first 50 feet of RMZ on both sides of a stream.
Where 50 percent of the trees greater than or equal to 8 inches DBH, or 10
trees per 100-foot segment of stream, whichever is greater, will be retained on
each side of the stream.
(9) The department shall use existing roads
in the SMZ or RMZ only if potential water quality impacts are adequately
mitigated and beneficial uses are fully protected.
AUTH:
77-1-202,
77-1-209,
77-5-201,
77-5-204,
MCA; IMP:
77-5-116,
77-5-204,
77-5-206,
77-5-207,
MCA