Transportation and Electricity Transmission - Energy Policy Analysis: A Conceptual Framework - page 216

machines and techniques are used to remove trees from a transmission right-of-way depending
on whether woodlands consist of mature trees, have large quantities of understory trees, or are
in sensitive environments such as a wooded wetland. These machines and techniques can range
from large whole-tree processors, which can cause rutting and compaction of the forest floor, to
hand-clearing with chainsaws in more sensitive environments. Timber removed for construction
of a high-voltage transmission line remains the property of the landowner. Small-diameter limbs
and branches are often chipped or burned. Wood chips may be spread on the right-of-way, piled to
allow transport by the landowner to specific locations, or chipped directly into a truck and hauled
off the right-of-way (PSC Wisconsin 2011).
A transmission line right-of-way can fragment a large forest into smaller tracts. Fragmenta-
tion makes interior forest species more vulnerable to predators, parasites, competition from edge
species, and catastrophic events such as blowdown during a storm. Continued fragmentation of a
forest can cause a permanent reduction in species diversity and suitable habitat. Loss of forested
habitat increases the number of common (edge) plants and animals that can encroach into what
were forest interiors. This encroachment can have impacts on the number, health, and survival of
interior forest species, many of which are rare. Edge species that can encroach into forest interiors
via transmission right-of-ways include raccoons, cowbirds, crows, deer, and box elder trees. Interior
forest species include songbirds, wolves, and hemlock trees (PSC Wisconsin 2011).
Construction vehicles may inadvertently bring into forest interiors invasive or nonnative plant
species. The opening of the forest floor to sunlight through tree-clearing of a right-of-way can
further encourage these aggressive, invasive species to proliferate. Problematic invasive species
include buckthorn, honeysuckle, purple loosestrife, and garlic mustard. Invasive species, once
introduced, have few local natural controls on their reproduction so they can easily spread. Their
spread can alter the ecology of a forest as they outcompete native species for sunlight and nutri-
ents, further reducing suitable habitat and food sources for local wildlife. A cleared right-of-way
increases human access into a forest, which may lead to trespassing and vandalism. It can also
provide recreation opportunities such as access for hunting, hiking, and snowmobiling. Impacts
to woodlands from transmission line construction can be minimized by avoiding routes that frag-
ment major forest blocks; adjusting pole placement and span length to minimize the need for tree
removal and trimming along forest edges; allowing tree and shrub species that reach heights of
twelve to fifteen feet to grow within a right-of-way; and following state guidelines for preventing
the spread of exotic invasive plant species and diseases (PSC Wisconsin 2011).
Archeological and Historical Resources
Archeological and historical sites are protected resources that are important and increasingly rare
tools for learning about the past. They may also have religious significance. Transmission line
construction and maintenance can damage sites by digging, crushing artifacts with heavy equip-
ment, uprooting trees, exposing sites to erosion or the elements, or making sites more accessible
to vandals. Impacts can occur wherever soils will be disturbed, at pole locations, or where heavy
equipment is used (PSC Wisconsin 2011).
State historical societies often have primary responsibility for protecting archeological and
historical resources. They manage records of all known sites that are updated as new information
becomes available. The database must be searched for any sites that might be located along any
proposed transmission routes. Route changes are seldom necessary. Judicious transmission pole
placement can often be used to span resources and avoid impacts to archeological and historical
sites. If during construction an archeological site is encountered, construction at the site must be