350-082-0280 Table 1 - Desired Forest Structure and Pattern | ||||||||
Vegetation Type1 | Forest Structure (Average % total canopy closure (cc) 2 | Typical Forest Openings Size (Disturbance caused) | Percent Openings at One Time | Leave Trees Includes all available remnant old forest | Average Down Wood Pieces 30 ft long per acre (scattered) | Average Snags Number of conifers per acre Snags are 20-40 ft in height | ||
Historic (Natural) | Desired | Historic (Natural) | Desired | |||||
West Conifer | 60-80% canopy closure Understory layer variable (0-60% of total cc) | Variable sizes with mosaic pattern, irregular shapes Mosaic fire 1-100 acres Catastrophic fire over 100 acres | Retain forested character Allow openings up to 15 acres (up to 5 acres in the foreground of KVAs) All openings 1 acre or less on National Forest land and all Open Space LUD Openings retain 1540% canopy closure | 10% (mosaic fire) up to 55% (catastrophic fire) Intense fire return interval is 300 years | Not to exceed 8% for West Coniferous Woodland Landscape Setting and not to exceed 4% for Gorge Walls, Canyons and Wildlands Landscape Setting Widely dispersed, variable sized mosaic of irregular shapes blending with existing openings | Leave 15% of existing trees per acre throughout opening and in clumps. Include 3 trees per acre of the largest size trees available | 18-25 pieces greater than 20" diameter at breast height (dbh) | 10 snags at 10"-20" diameter at breast height (dbh), and 7 snags greater than 20" dbh |
East Conifer (Ponderosa Pine/Douglas fir) | 40-80% canopy closure Understory layer less than 25% of total cc | Few openings due to low intensity fires 1/4 to 2 acres | Openings less than 1 acre Openings have 0-40% canopy closure Openings widely dispersed | 1-10% | 1-10% (% by vegetation type) | No leave trees required | 3-6 pieces greater than 20" dbh | 5 snags at 10"-20" dbh and 3 snags greater than 20" dbh |
Ponderosa Pine/ Oregon Oak | 25-60% canopy closure Understory layer greater than 25% of total cc. | Most natural openings due to poor soil. Disturbance openings few | Openings less than 1 acre Openings have 0-25% canopy closure Openings widely dispersed | 1-10% | 1-10% (% by vegetation type) | No leave trees required | 1-3 pieces greater than 20" dbh | 5 snags at 10"-20" dbh and 3 snags greater than 20" dbh Oak snags can be counted if already dead or partially dead |
1 Map available at the Forest Service, National Scenic Area Office, Hood River, Oregon.
2 Does not apply to openings.
Or. Admin. Code § 350-082-0280
Statutory/Other Authority: ORS 196.150, RCW 43.97.015, 16 USC § 544f(l)
Statutes/Other Implemented: ORS 196.150, RCW 43.97.015, 16 USC § 544f(l)