Summary: The Regional Ecosystem Office (REO) interagency Late-Successional Reserve (LSR) Work Group has concluded its review of the documents provided by the Mt. Hood National Forest regarding proposed activities in LSRs within Alternative B of the 2007 Plantation Thinning Project Environmental Assessment (EA). The REO, based upon the review by the LSR Work Group, concurs with the Mt. Hood National Forest in its findings of consistency with the Standards and Guidelines (S&Gs) under Northwest Forest Plan (NWFP) for the 2007 Plantation Thinning Project.

Basis for the Review: Silviculture, risk reduction and salvage treatments in LSRs are subject to REO review under the NWFP S&Gs (C-12-15). As required by the NWFP S&G (C-11), the Mt. Hood National Forest prepared a Late-Successional Reserve Assessment (LSRA) for the North Willamette LSRs. The North Willamette LSRA was completed and reviewed by the REO in 1998. Projects within the LSRs covered by the assessment are exempted from further REO review provided they are consistent with the LSRA criteria and S&Gs. Activities which are not included in the LSRA or do not meet the treatment criteria identified in the assessment are subject to REO review.

Background and Project Description: The Mt. Hood National Forest is proposing commercial thinning in the Collawash and Roaring River LSRs. The thinnings are being designed to accelerate the development of mature and late-successional stand conditions, specifically habitat for northern spotted owls.

The LSR stands within the 2007 Plantation Thinning project occur within the Roaring River (207A) and Collawash (RO 210) LSRs and comprise approximately 955 and 354 acres, respectively. These stands are plantations between 32 and 61-years-old and are considered mid-seral stands. Canopy closure is 70 to 90 percent with relative densities greater than 70. All the units were originally clearcut back in the 1940’s to 1970’s. Few snags or residual trees were left in the stands after harvest. However, varying amounts of down woody debris remained post-harvest and were usually dependent on the type and success of site preparation techniques used during that time. Trees are beginning to experience growth suppression and some mortality is occurring; mainly in trees smaller than 10-inch d.b.h. In the Roaring River LSR, the quadratic mean diameter is 11-inches d.b.h. in the 32 to 49- year-old stands, and 14-inches d.b.h. in the 50 to 61-year-old stands. In the Collawash LSR the age of the stands vary from 40 to 50 years, and have a quadratic mean diameter of 13-inches d.b.h.

The cost of creating or leaving down wood in the amounts recommended by the LSR assessment would not allow for an economically viable timber sale. No other funding source is available to implement the thinning project, thus without an economically viable timber sale the benefits gained in terms of accelerating the development of other late-successional characteristics would not be realized. Thus, the proposed thinning design will not meet the criteria in the North Willamette LSRA for down wood amounts – 10 to 15 percent cover within 5 years, and the Forest has brought the project to REO for review.

Review of the Project: The activities reviewed by the LSR Work Group were those proposed in LSRs under Alternative B of the EA: 2007 Plantation Thinning Project. The Work Group reviewed documents provided by the Mt. Hood National Forest, which included:

1. 2007 Plantation Thin – LSR Portion, Clackamas River Ranger District, Mt. Hood National Forest, January 2007.
2. Justification for Managing Below Levels of Down Woody Debris as Specified Within the North Willamette Late-Successional Reserve Assessment in the 2007 Plantation Thin, Mt. Hood National Forest, Clackamas River Ranger District, 1/23/07.

The Work Group’s review was based on the information within these documents and briefings. The interagency LSR Work Group review concluded that the proposed treatments in LSRs meet the objectives for managing LSRs. This conclusion was reached in part for the following reasons:

• Based on analysis using unharvested inventory plots from DecAID to reflect historical range of variability (HRV), the Middle Clackamas watershed is above HRV for moderate to high amounts of down wood. Even though the LSRA criteria for 10 to 15 percent down wood will not be met across the thinning units, at the landscape scale down wood levels are consistent with the objectives for managing LSRs.
• The LSRs are currently below Desired Future Condition (DFC) of 70 percent late-successional habitat. Mid-seral stands currently are lacking late-successional characteristics of large trees and multiple stories. This project will move towards DFC for the LSRs.

• Based on modeling stand growth using the FVS (Forest Vegetation Simulator) system, thinning these young stands now would result in a size class distribution and canopy structure that more closely resembles the late-successional habitats that meet the DFCs identified in the LSRA in a much shorter length of time than if no treatment occurred.

Conclusion: Based upon the interagency REO LSR Work Group’s review and conclusions, the REO concurs with the Mt. Hood National Forest’s conclusion that silviculture activities proposed in the 2007 Plantation Thinning Project are consistent with the NWFP S&Gs.

cc:
Gary Larsen, Forest Supervisor, Mt. Hood National Forest
Andrei Rykoff, District Ranger
Phil Mattson, FS
Cal Joyner, FS
Jim Rice, Team Lead, FS
LSR Work Group