Range of Natural Variation
on Chippewa and Superior National Forests
Range of natural variation (RNV) refers to the mixture of different kinds of trees that thrived historically in the forests before major logging. Forest diversity is measured in acres of various forest types, and tree ages.
When RNV is out of whack - as has resulted from 100 years of logging - the forest loses wildlife habitat and scenic and recreational settings. When habitat declines, rare plants and animals can become threatened with extinction.
Analysis of RNV in Chippewa & Superior
National Forests
provides stark examples of logging consequences
| Chippewa | RNV for white pine 17-30% | Currently 1% white pine |
| Superior | 200+ year old trees made up 27-40% of pre-logged forest | Currently 4% undisturbed with little white pine of any age |
More analysis is provided on the plants page.
The U.S. Forest Service's proposed forest management plan, Alternative E, doesn't do enough to restore forests to an optimal range of natural variation.
- If the Forest Service really wants to move the forests closer to Range of Natural Variation, why not assign all logging projects in the first ten years some restoration purpose? That will provide plenty of aspen, and get a head start on restoring diminished tree species.
- It is feasible to achieve logging goals and restore forest types to RNV. For example, protect white pine stands and clumps from logging until 50% of the 100 year goals for cover type restoration of white pine are achieved.
- Quantified objectives for more multi-aged older forest patches are needed to provide accountability and shift some restoration to the first decade of the plan.
- The plan also needs to identify and designate old growth as protected from logging to exceed the acres assumed to be federally protected in the GEIS on Timber (15,000 acres SNF/12,400 CNF).