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Forest Finance
Fencing for Forest Regeneration:
Does it Pay?
Introduction
Does fencing for forest regeneration
pay? The short answer is “yes”—if you
want a diverse and sustainable forest
resource in the future. Pennsylvania’s
hardwood forests usually regenerate
naturally after a harvest. Normally,
stump or root sprouts, small seedlings
and saplings, and stored seed provide the ingredients that determine
the composition of the next forest.
Therefore, before harvesting, you
should consider the quantity, quality,
and species of advanced regeneration
and the potential impact of deer
browsing—perhaps the single most
important factor limiting regeneration
across the Commonwealth. Deer prefer to browse seedlings, saplings, and
sprouts of the most valuable timber
species. Recognizing and addressing a
browsing problem before harvesting is
critical to the successful establishment
of a forest stand for the future.
If deer density is currently high or if
your forest has had high deer density
in the past, there may be insufficient
regeneration to successfully replace
trees taken in harvest (Marquis and
Brenneman 1981, Jones et al. 1993).
Evaluating the species composition
and quantity of advanced regeneration provides one indicator of deer
density. Three signs of deer damage
are undesirable plant species, lack of
desirable understory vegetation, or a
conspicuous browse line. An unfortunate but true observation is that deer
tend to prefer timber species as browse
and ignore less desirable species such
as striped maple, beech, and ferns. If
the stand is deplete of understory vegetation, and if this depletion has been
caused by deer, you may need to take
measures to create advanced regeneration (understory vegetation) before
a harvest, especially if your plans call
for a harvest intensity that moves the
stand toward regeneration.
Perhaps the most visual method of
identifying a deer problem is the
browse line—the tree height a deer
can reach to find twigs and leaves.
Vegetation missing from the lower
part of trees and shrubs indicates a
deer problem. Deer also eat wildflowers—the absence of some and the
overabundance of others may indicate
a possible deer problem. The Pennsylvania Bureau of Forestry and the
Pennsylvania Game Commission have
data on deer populations for your
county and can help you determine
whether deer are a problem.
The most effective and economical way to control and prevent deer
damage is hunting. A successful deer
harvesting program can minimize deer
damage and foster regeneration. Along
with hunting, and depending on the
site, regeneration may require herbicide use to suppress unwanted grasses,
ferns, and woody plants that interfere
with the establishment of desirable
plants. Various deer damage control
methods such as repellents, tree shelters (tubes), trapping and transferring
deer, or fertility control are either very
expensive or unproven in Pennsylvania
forests. If one is regenerating or planting trees on only a few acres, then tree
shelters may prove more cost effective
than fencing, but some studies suggest
that shelters may inhibit growth,
harbor pests, and increase diseases.1
Other than state-regulated hunting,
fencing may be the next best option
for regenerating desirable tree and
plant species.
1. Economic analysis shows that on five acres
or less, planting 400 trees per acre, tree shelters
cost less than a fence—assuming the tubes
cost $2 apiece and the fence costs $2 per linear
foot installed. For more than five acres, a fence
becomes more cost effective. For more detail
on concerns about growth rates and mortality
in tree shelters, see Forest Finance 6.
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For numerous reasons, private forest
landowners are reluctant to fence.
Fences may reduce access landowners
enjoy. Fences also may be visually
unpleasant and detrimental to aesthetic values. Costs, however, most likely
have the greatest effect on decisions to
fence. One way to rationalize fencing
costs is as an up-front investment to
ensure a future forest that provides a
sustainable flow of timber, wildlife,
and other benefits. Excessive deer
browsing can create a future forest
with little or no valuable timber,
devoid of aesthetically pleasing and
ecologically important shrubs, herbs,
and wildflowers normally found in
Pennsylvania’s diverse forests.
Questions to consider
before fencing
When considering a fence, ask yourself the following questions:
1. What effect does deer browsing
have on forest values?
Two types of forest values are lost to
deer overbrowsing. One is the lost
value of future timber products, if
deer damage or destroy them at a
young age. Obtaining revenues from
timber or other products requires
long-term commitments that often
may extend beyond the owner’s
lifetime.
Landowners also enjoy other values
such as improved wildlife habitat,
recreation, and biodiversity. These
so-called “amenity values” are difficult
to price, but most people recognize
them as important forest benefits. By
assessing their objectives, landowners
will determine how important these
values are. In so doing, they may
discover that they need to take steps
to control deer browsing to achieve
certain objectives.
2. How much does deer fencing
cost?
Fencing costs depend on the type of
fence, length needed, and site and
installation conditions. Various fences
are designed specifically to exclude
deer. Most popular are high-tensile
electric and woven wire fences. Table
1 compares these two fence types.
Another fence type becoming more
popular is the plastic variety. It is
similar to the woven wire—a tightly
interwoven mesh.
The type you choose depends on
several factors and ultimately on your
preference. No fence excludes all deer.
Deer learn how to get through, over, or
under fences. In fact, having a few deer
inside a fence is potentially beneficial
if the fenced area is large enough since
their selective browsing can reduce
competition among some plant or tree
species. Working with a knowledgeable
resource professional is essential when
dealing with these types of issues. Visit
the Penn State Extension Natural Resources website at extension.psu.edu/
natural-resources for a list of fencing
contractors and suppliers.
Table 1. Comparison of high-tensile electric wire fencing to woven wire fencing.
Electric
Woven wire
Recommended height
Six to nine strands: 5–7 feet 8 feet
Costs $1.00–1.50
(installed per linear foot)
$1.50–2.50
Installation Fewer posts and bracing
Requires more posts
Maintenance
High Lower
ReusableYes
No
Deer behavior Learn to ignore it
More effective at keeping deer out
Weather
Problems with grounding—
dry soils, snow
No problem
Topography
Better on flatter terrain
No problem
Human contact
Make sure fence is well
posted to prevent shock
No problem
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A fence has done its job when the
regeneration is successful and out of
reach of deer. This may require five
to ten years. Based solely on installation cost, the electric tensile wire
fence is cheaper. It also, in principle,
is reusable, perhaps an important
factor if you are harvesting different
areas every five to ten years. You can
finish establishing regeneration on one
section, remove the fence, and reuse
it in another section. The woven wire
fence, although salvageable as scrap,
is not readily reusable because of the
difficulty in maneuvering it from one
place to another.
The woven wire fence works better
than the electric fence at excluding
deer. However, as mentioned above,
deer sometimes are able to jump
over or go under any fence. A higher
electric fence, with more strands to
narrow the space between wires, may
be more effective. Obviously, electric
fences deter deer by shocking. The
objective is to teach deer to avoid the
shock and stay away. If deer learn to
ignore the shock, or if there is a power
loss or reduction, the electric fence’s
value drops. It is best to train deer
early in the process.
Electric fences require continuous
maintenance, which may involve
weekly visits (Selders and McAninch
1987). Electric fences also require
signage (indicating electrification),
careful and specific installation,
specialized equipment, and energizers.
The options for energizers include
plug-in, battery, and solar. Plug-in
energizers (if the fence is close to a
commercial electric source) are the
most economical and require the least
maintenance.
Finally, cost depends on the area
fenced and the site conditions. The
fewer acres you fence, the more
expense is attributable to fixed costs.
The costs of hauling heavy materials,
establishing electrical equipment, and
erecting the fence per unit length are
usually fixed regardless of the area
fenced. Variable fencing costs, including labor and materials, increase
as the fenced area increases, but at a
decreasing rate. The larger the area,
the less it costs per acre protected.
(Table 2 shows that doubling the area
does not double the length of fencing
required.) On average, deer fences in
Pennsylvania enclose 20 to 40 acres.
Fencing large areas may not be
practical because of the terrain or the
difficulty of removing deer from the
area before “closing” the fence. Terrain
conditions also affect construction
costs. An area that needs little site
preparation such as clearing obstacles
is less expensive to fence. Generally,
installers clear the fence perimeter of
vegetation and debris before fencing
to allow bulldozer, four-wheeler, or
skidder travel. Also, this open buffer
allows deer to better see the fence and
avoid it.
Expect lower costs if the land is relatively flat, the fenced area is relatively
square (fewer corners), and trees serve
as posts. Your costs will be significantly lower if you self-install the fence. If
you use an outside contractor, prepare
the contract in writing, showing work
specifications and responsibilities of
each party.
3. How do I cover the cost of
fencing?
Like any rational investment,
fencing costs should return benefits.
The benefits from fencing include
better wildlife habitat, future timber
revenues, and other forest values
important to the landowner. However,
fencing is a long-term investment—
the financial benefits might not
happen for many years. If the decision
to fence is made purely for future
timber revenues, you can use financial
tools such as cost-benefit analysis to
estimate returns from the investment.
The following example depicts how
much future revenue is necessary to
make the fencing investment “pay
off ” at different interest rates. This
example uses a 20-acre square fence
costing $2.00 per linear foot, installed
for $7,468 (3,734 linear feet x $2).
On a per-acre basis, the cost is $7,468
÷ 20 = $373.40. Table 3 shows future
timber values needed per acre to offset
the up-front fencing costs of $373.40
per acre. This example ignores all
future fence maintenance costs. At low
Table 2. Linear feet of fencing
required to enclose different square
acreages.
Square acres
Linear feet
51,868
102,640
interest rates and shorter rotations,
less revenue from a future timber
harvest pays for the fencing. Longer
rotations require more future revenue
to make up for the fencing costs. For
example, at 80 years with a 6 percent
interest rate, you must expect harvest
revenue per acre of $39,504 to make
the fencing investment pay off.
The revenues in Table 3 are for timber
values only. In some cases, landowners
look at fencing solely from a financial
perspective and reflect on the profitability of the investment. The decision
to fence, however, usually involves
more than just timber revenues; it
includes sustaining a forest that will
provide many other benefits.
Paying for the fence is a cost of regenerating a forest. How can a landowner
cover this cost? One way is to set
aside some of the revenues from a
timber harvest. Another way is to take
advantage of the federal reforestation
deduction and amortization offered
to forest landowners. Deer fencing is
recognized as a reforestation expense
for tax purposes. Taxpayers can elect
to deduct up to $10,000 of qualified
reforestation expenses in the year it
occurs, and amortize qualified expenditures over the $10,000. In the
example in the text, the landowner
would deduct all $7,468 in the year
the fencing was installed.
203,734
505,903
1008,348
Table 3. Future timber revenues per acre needed to offset fencing costs of $373.40
per acre, using different discount rates and rotation ages.
Rotation age (years)
Discount rate
60
4%
$3,928$8,606 $18,858
6%
$12,317$39,504 $126,695
8%
$37,809 $176,228$821,390
4
80
100
Summary
References
Landowners want to see a sustainable
forest on their land for many reasons
other than timber income. Ensuring
a future forest after a timber harvest
may require an investment in fencing. The benefits of fencing include
not only a stand of valuable timber
but also the many other values of a
sustainable forest. Fencing is a gift to
the future if timber, improved wildlife habitat, plant diversity and other
benefits are a landowner’s goal. Fencing costs are part of an overall forest
management plan. The choice of
fence type depends on site conditions,
landowner preferences, and costs.
The decision to fence should occur
early, before the harvest and while the
option to establish regeneration is still
available. Deciding to harvest without
considering regeneration might not
produce an outcome that sustains
forest values. Once the seed source is
gone or deer eliminate regeneration—
allowing ferns, grasses, or other vegetation to become established—fencing
might be fruitless. Regenerating a
forest with significant deer damage
might require more expensive remedial action in addition to fences.
Jones, S. B., D. DeCalesta, and S.
E. Chunko. 1993. “Whitetails are
Changing our Woodlands.” American
Forests.
Marquis, D. A., and R. Brenneman.
1981. The Impact of Deer on Forest
Vegetation in Pennsylvania. Forest Service General Technical Report NE-65.
Selders, A. W., and J. B. McAninch.
1987. High-Tensile Wire Fencing. Ithaca, N.Y.: Northeast Regional Agricultural Engineering Service.
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Prepared by Michael Jacobson, associate
professor of forest resources.
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Produced by Ag Communications and Marketing
© The Pennsylvania State University 2006
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