OAR 629-642-0100
General Vegetation Retention Prescription for Type F Streams
(1)
Intentionally left blank —Ed.(a)
Operators shall apply the vegetation retention requirements described in this rule to the riparian management areas of Type F streams. Vegetation retention requirements for Type SSBT streams adjacent to harvest type 2 or harvest type 3 units are described in OAR 629-642-0105 (General Vegetation Retention Prescriptions for Type SSBT Streams) and other water protection rules.(b)
Segments of Type F streams that are different sizes within an operation shall not be combined or averaged together when applying the vegetation retention requirements.(c)
Trees left to meet the vegetation retention requirements for one stream type shall not count towards the requirements of another stream type.(2)
Operators shall retain:(a)
All understory vegetation within 10 feet of the high water level;(b)
All trees within 20 feet of the high water level; and(c)
All trees leaning over the channel.(3)
Operators shall retain within riparian management areas and streams all downed wood and snags that are not safety or fire hazards. Snags felled for safety or fire hazard reasons shall be retained where they are felled unless used for stream improvement projects.(4)
Notwithstanding the requirements of section (2) of this rule, vegetation, snags and trees within 20 feet of the high water level of the stream may be felled, moved or harvested as allowed in other rules for road construction, yarding corridors, temporary stream crossings, or for stream improvement.(5)
Operators shall retain at least 40 live conifer trees per 1000 feet along large streams and 30 live conifer trees per 1000 feet along medium streams. This includes trees left to meet the requirements described in section (2) of this rule. Conifers must be at least 11 inches DBH for large streams and 8 inches DBH for medium streams to count toward these requirements.(6)
Operators shall retain trees or snags six inches or greater DBH to meet the following requirements (this includes trees left to meet the requirements of sections (2) and (5) of this rule):(a)
If the live conifer tree basal area in the riparian management area is greater than the standard target shown in Table 2 where the harvest unit will be a harvest type 2 or type 3 unit or Table 3 where the harvest unit will be a harvest type 1, partial harvest, or thinning, operators shall retain live conifer trees of sufficient basal area to meet the standard target.(b)
If the live conifer tree basal area in the riparian management area is less than the standard target (as shown in Table 2 where the harvest unit will be a harvest type 2 or type 3 unit, or Table 3 where the harvest unit will be a harvest type 1, partial harvest, or thinning) but greater than one-half the standard target shown in Table 2, operators shall retain all live conifer trees six inches DBH or larger in the riparian management area (up to a maximum of 150 conifers per 1000 feet along large streams, 100 conifers per 1000 feet along medium streams, and 70 conifers per 1000 feet along small streams).(c)
If live conifer tree basal area in the riparian management area is less than one-half the standard target shown in Table 2:(A)
Operators may apply an alternative vegetation retention prescription as described in OAR 629-642-0600 (Alternative Vegetation Retention Prescriptions) where applicable, or develop a site specific vegetation retention prescription as described in OAR 629-642-0700 (Site Specific Vegetation Retention Prescriptions for Streams and Riparian Management Areas); or(B)
Operators shall retain all conifers in the riparian management area and all hardwoods within 50 feet of the high water level for large streams, within 30 feet of the high water level for medium streams, and within 20 feet of the high water level for small streams.(7)
In the Coast Range, South Coast, Interior, Western Cascade, and Siskiyou geographic regions, hardwood trees and snags six inches or greater DBH may count toward the basal area requirements in subsection (6)(a) of this rule as follows:(a)
All cottonwood and Oregon ash trees within riparian management areas that are beyond 20 feet of the high water level of large Type F streams, may count toward the basal area requirements.(b)
Up to 10 percent of the basal area requirement may be comprised of sound conifer snags at least 30 feet tall and other large live hardwood trees, except red alder, growing in the riparian management area more than 20 feet from the high water level and at least 24 inches DBH.(8)
In the Eastern Cascade and Blue Mountain geographic regions, hardwood trees, dying or recently dead trees and snags six inches or greater DBH may count toward the basal area requirements in subsection (6)(a) of this rule as follows:(a)
The basal area of retained live hardwood trees may count toward meeting the basal area requirements.(b)
Up to 10 percent of the basal area retained to meet the basal area requirement may be comprised of sound conifer snags at least 30 feet tall.(c)
For small Type F streams, the maximum required live conifer tree basal area that must be retained to meet the standard target is 40 square feet. The remaining basal area required may come from retained snags, dying or recently dead trees, or hardwoods if available within the riparian management area.(9)
Notwithstanding the requirements indicated in this rule, operators may conduct pre-commercial thinning and other release activities to maintain the growth and survival of conifer reforestation within riparian management areas. Such activities shall contribute to and be consistent with enhancing the stand’s ability to meet the desired future condition.(10)
When determining the basal area of trees, the operator may use the average basal area for a tree’s diameter class, as shown in Table 4, or determine an actual basal area for each tree. The method for determining basal area must be consistent throughout the riparian management area.(11)
Intentionally left blank —Ed.(a)
For large and medium Type F streams (not including Type SSBT streams), live conifer trees retained in excess of the active management target shown in Table 2 and hardwoods retained beyond 20 feet of the high water level of the stream that otherwise meet the requirements for leave trees may be counted toward requirements for leave trees within harvest type 2 or harvest type 3 units (pursuant to ORS 527.676 (Leaving snags and downed logs in harvest type 2 or 3 units)).(b)
For small Type F streams (not including Type SSBT streams), all retained live trees that otherwise meet the requirements for leave trees may count toward requirements for leave trees within harvest type 2 or harvest type 3 units (pursuant to ORS 527.676 (Leaving snags and downed logs in harvest type 2 or 3 units)).(12)
Trees on islands with ground higher than the high water level may be harvested as follows:(a)
If the harvest unit is solely on an island, operators shall apply all the vegetation retention requirements for a large Type F stream described in this rule to a riparian management area along the high water level of the channels forming the island.(b)
Otherwise, operators shall retain all trees on islands within 20 feet of the high water level of the channels forming the island and all trees leaning over the channels. In this case, conifer trees retained on islands may count toward the basal area requirement for adjacent riparian management areas so long as the trees are at least 11 inches DBH for large streams and eight inches DBH for medium streams.(13)
When applying the vegetation retention requirements described in this rule to the riparian management areas, if an operator cannot achieve the required retention without leaving live trees on the upland side of a road that may be within the riparian management area and those trees pose a safety hazard to the road and will provide limited functional benefit to the stream, the State Forester may approve a plan for an alternate practice to modify the retention requirements on a site specific basis.
Source:
Rule 629-642-0100 — General Vegetation Retention Prescription for Type F Streams, https://secure.sos.state.or.us/oard/view.action?ruleNumber=629-642-0100.