Focus Species Forestry - Maine Audubon

Large Ownerships: On a typical township in the unorganized territories, Hunter’s rule
would suggest that equal areas should be allocated to single tree and small group
selection management (openings less than 0.25 acre), large group selection (0.25-2.5
acres), patch cuts and small shelterwood cuts or clearcuts (2.5-25 acres) and large
shelterwood cuts or clearcuts (25-250 acres). Within the shelterwood and clearcut
categories, applying Hunter’s rule would suggest allocating equal areas to different
opening sizes (e.g., the area in cuts from 25 to 75 acres should equal the area in patches
from 75 to 250 acres).
Small Ownerships: Create a diversity of
opening sizes appropriate to the ownership.
Hunter (1999) suggests that the same
general allocation approach used for large
ownerships can be used on small parcels,
but the maximum size of even-aged units
(shelterwood or clearcut) will be much
smaller than on large tracts of commercial
timberland.
This approach to creating a diversity of patch sizes
is probably best viewed as a conceptual model
rather than a quantitative management
prescription. It is a more aggressive approach to
creating large patches than would occur under
natural conditions, so should be used with caution.
However, it is more conservative than much of the
management seen today on industrial and investor
timberlands. Individual stand conditions, landscape
features, landowner objectives, and focus species
habitat will take priority. Nonetheless Hunter’s
rule provides a useful context for evaluating the
diversity of patch sizes in the current landscape
and how that diversity will be impacted by
management prescriptions.
Limit the Area in Single-Aged Stands
If the harvests result in nearly complete overstory
removal, the result will be a harvesting regime that
is much more aggressive than that resulting from
natural disturbance regimes. Even “stand-replacing
disturbances” such as fire, wind, or spruce
Habitat Management and the
Maine Forest Practices Act
Maine’s Forest Practices Act (FPA) limits the size
of clearcuts and requires separation zones be
retained that meet specified standards. Depending
on the size of the clearcut, the separation zones can
be harvested in approximately 10-15 years. Thus,
clearcutting could be used to create large patches of
early successional habitat consisting of a mosaic of
stands that are separated by 10-15 years in age.
Alternatively, under the FPA there is no limit on
patch size that can be created with the shelterwood
system. When even-aged management is used:
• Whenever possible, use shelterwood harvesting
instead of clearcutting.
• Avoid a uniform application of similar-size
harvest units evenly distributed across the
landscape. See recommendations above on
creating a balanced diversity of patch sizes,
which will result in areas with high levels of
habitat interspersion as well as a few large,
relatively uniform patches.
• Follow the stand-level guidelines for retaining
snags, cavity trees, downed logs and patches of
older forest in even-aged management areas.
• Maintain travel corridors of mature forest in a
landscape where shelterwood and clearcutting
are used.
• Maintain adequate mature forest at all times,
including some areas that do not “shift” across
the landscape (i.e., areas where single-tree
selection, group selection, or two-aged
management are used.
budworm result in irregular two-aged stands. In a review of silviculture and natural disturbance
regimes in Maine, Seymour et al. (2002) observe that an artificial landscape pattern exists when
even-aged stands exceed 15-25% of the landscape. The shelterwood-with-reserves method (see
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Focus Species Forestry