Stands of Old Growth Trees:
MRC has identified approximately 105 acres of "never-harvested" (FSC Type I) old growth stands. These acres will be permanently protected by MRC from any kind of harvesting. MRC also has approximately 714 acres of previously harvested (FSC Type II) old growth stands where significant old growth characteristics are still present. The residual old growth trees and late successional characteristics of these stands are protected and only silviculture such as thinning from below, is allowed to enhance or extend these stands.
Individual Old Growth Trees:
The remaining previously logged second-growth forests on MRC lands are estimated to contain up to 12,000 scattered residual old growth trees in very low densities. A substantial proportion of these old trees are being preserved based on a protection policy that is defined by age, size, function and characteristics specific to particular species. As far as we know, MRC is the only large industrial forestland owner to have such a comprehensive old growth protection policy.
Trees preserved from harvesting include:
- Any redwood tree, 48" dbh and larger, established prior to 1800.
- Any Douglas-fir tree, 36" dbh and larger, established prior to 1800.
- Any tree established prior to 1800 (conifer or hardwood), regardless of diameter size, with a preponderance of species-specific old growth characteristics
- In addition to the above, MRC retains any tree (conifer or hardwood), established prior to 1800, that cannot be replaced in size or ecological function within 80-130 years, regardless of diameter or presence of old growth characteristics. Generally, this fourth "trigger" is applicable to areas of exceptionally low site, for example-pygmy forest, pygmy transition soil, serpentine soils, site five and shallow rocky outcroppings.
SPECIES SPECIFIC OLD GROWTH CHARACTERISTICS
Redwood Old Growth Characteristics
- Trees generally are in the upper 20% diameter class of the species on site
- Deep, plate-like bark patterns, fire resistant
- Flattened or irregular crowns, highly complex structure
- Highly reiterated crowns (multiple sprouting, replicated growth patterns)
- Large limbs, in excess of 6-8 in diameter
- Crown debris accumulation
- Platforms
- Cavities, partial snag formation
- High presence of complex lichens and moss
- Cat-facing or basal burn cavities
- Douglas-fir Old Growth Characteristics
- Trees generally are in the upper 20% diameter class for the species on site
- Bark deeply fissured, thick and fire resistant
- High presence of lichens and moss, where crown soils present, ferns
- Large lateral limbs in excess of 8-10 inches in diameter
- Fattened, irregular crowns with lower limbs with signs of decay and crown thinning
- Conks
- Partial sagging in tops
- Broken out tops
- Crown debris accumulation
- Specific to fir, trees along the margins of vegetation types, which represent the pioneer, tree individuals, which reoccupied the sites following disturbances. These normally will have limbs extending nearly to the ground and at times is wind shaped.
Hardwood Old Growth Characteristics (tanoak, live oak, black oak, madrone, laurel, chinquapin)
- Trees generally are in the upper 20% diameter class for the species on site
- Flattened or irregular crowns, highly complex structure
- Multiple branching crowns with few large well developed main limbs
- Large limbs, in excess of 4-12 inches in diameter
- Crown debris accumulation
- Platforms
- Cavities, partial snag formation
- Crown die-back
- Cat-facing or basal burn cavities
SCREEN TREES
In addition to the policies above, generally it's been MRC practice to maintain screen trees around retained old growth trees. Where they exist, screening trees are generally maintained to provide additional cover. The screen trees will usually be immediately adjacent trees or trees which are close enough to influence the growth and form of the retained old growth tree. These may have intermingling crowns or crowns which if left to grow will eventually intermingle with the retained old growth crown. For redwoods, trees with shared root systems (i.e. crown sprouts) indicated suitable candidates for screen trees.
SPECIAL CIRCUMSTANCES
In rare instances, the cutting of old growth trees is required for road construction, skyline corridors, or for other workplace safety considerations. Trees cut under these special circumstances will be left in the forest to provide large wood on the forest floor and for wildlife refuge. Old growth trees mistakenly cut due to misjudgment of age will also be left in the woods.
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