Deer Predation on a White Cedar Restoration Project
in Northwestern Wisconsin
by
Herbert Wagner
herbswoods@yahoo.com
"White cedar swamps have become a rarity because of poor regeneration due to deer herbivory" -- Northwest Sands, Ecological Landscapes of Wisconsin
Note> Project Updates can be found following Section #11 <Note
1) Northern White Cedar Restoration Project History
In the mid-1980s we began restoring northern white cedar trees on 30 acres in Wisconsin's
Northwest Sands region. Young white cedar transplants ranging in height from 3 to
12 inches were planted on suitable habitat. These small trees were gathered from
highway widening projects in Douglas and Bayfield counties. One healthy specimen
was recovered growing from railway ballast at legend-haunted Penokee Gap.
Early results were mixed. Lack of experience and poor techniques resulted in
some losses.
After surface dressings of bog peat and wood ash fertilizer were applied on upland
sites much better results were obtained. Also successful were experiments with rooting
cedar hardwood cuttings in sphagnum moss. The oldest and most established trees had
reached a height of around 15 feet and were producing cones and a seed crop when
disaster struck. Although previously not a serious problem, wintering deer now moved
in with an insatiable appetite for green cedar foliage. In a short time many smaller
trees were stripped bare by predatory deer.
Faced with the prospect of continual winter deer browsing the project would either
have to be abandoned or taken to a new level. In the following account we provide
an overview of the restoration work to date along with our observations and findings.We
also describe future management techniques that should be taken if this cedar restoration
project is to continue. Hopefully others may benefit from our mistakes and successes.
2) The Tree of Life
The
northern white cedar (Thuja occidentalis) is a member of the Cupressaceae family
which includes cypress, cedars, and
junipers. The cedar is a stocky, medium-sized tree that
grows to 50 feet in height and 2 to 3 feet in diameter. This resinous and pleasantly
fragrant evergreen has thick foliage exhibiting a flat scale-like needle pattern.
Often found growing on moist, rich, cool sites, the white cedar forms highly aesthetic
stands on peaty soils around lakes, wetlands, and rivers. It has been widely adapted
as a landscape tree.
Also known as arborvitae or "the tree of life" the name is an honest one.
In 1535-36 the French explorer Jacques Cartier learned from an Indian named Domagaia
how to cure scurvy by drinking an infusion made from the cedar's Vitamin C rich needles.
By the mid-16th century the white cedar was being cultivated in France and soon all
over Europe.
The "tree of life" name might also be applied to the white cedar's tenacity
for life. Ancient specimens found growing from cliff faces on the Niagara Escarpment
in Wisconsin have been dated at over 600 years old (Kahler, 2005). Examples found
growing on cliffs in Canada exceed 1000 years in age. Such toughness and longevity
serves as an inspiration for anyone trying to restore white cedar in areas with high
deer populations.
While not the largest evergreen tree in the forest, the cedar may be the most exotic
and otherworldly. There is something almost human-like in the cedar's nodding young
form, haunting aroma, soft foliage, and sensual smooth fibrous bark. To the Ojibwe
people the white cedar (giizhik) was considered sacred and was used for purposes
ranging from canoe building to the fragrant essence of the ceremonial smudge. If
spirits do inhabit trees the white cedar would be foremost in this category.
3) Natural Reproduction Rare
While the whitetail deer (Odocoileus virginianus) enjoys an ally in the powerful
hunting lobby and is protected 
by DNR regulations, the white cedar enjoys no such lobby
or champion. After the deer rifles of November fall silent and most humans have quit
the woods another slaughter quietly begins. This time, however, there is no wily
concealment or fleet-footed escape. This time deer are not the prey animal but the
voracious predator of young white cedars and other tree species. Years of growth
can be wiped out and small saplings killed outright by wintering deer. Anyone who
has tried growing white cedars as ornamentals with deer present know what a problem
these large herbivores can be. Attempting to restore white cedar on wild habitat
is an even greater challenge.
Due to deer predation, natural reproduction of white cedar is virtually nonexistent
in most areas. The destruction of seedlings and young trees effectively cuts off
recruitment of future adult trees. Add the fact that white cedar lumber is commercially
valuable for its decay-resistant properties, and it becomes apparent that the species
is under attack at both ends of its life span. As one researcher noted: "We
have a cedar resource that is aging, deer herds are larger now than ever before,
and stumpage prices for cedar increase every year. The pressure on this resource
has never been higher and if things continue as they are, it is certainly doomed."
(Miller, 1990).
The only locales in northern Wisconsin we have observed natural reproduction of white
cedar lay outside the Northwest Sands region. On heavier soils in Douglas and Ashland
counties we have seen young cedars sprouting along the edge of busy highway corridors.
In Douglas, Bayfield, and Ashland counties we have encountered cedar reproducing
on steep rocky slopes and cliffs.
Along
highway corridors traffic patterns and resultant deer mortality probably outweighs
to some degree the lure of this food source. However, these highway trees normally
exhibit both browsing and/or mowing damage. On rocky talus slopes cedar regeneration
probably occurs because deer with their spindly legs may shun such rough ground.
Even so, deer browse damage on talus slope cedars is also evident. Only on steep
rock outcrops do cedars appear immune from deer predation. However such habitat is
marginal and limited in extent.
From these observations it appears that successful natural reproduction
of white cedar in northwestern Wisconsin is largely absent. More typically one finds
mature cedars growing in isolation or in stands with no significant reproduction.
Here in the Northwest Sands region there is almost no habitat where successful cedar
reproduction can take place. In this region of gently rolling pitted glacial outwash
and wetlands there are no steep rocky slopes and no cliff faces. Here deer are abundant,
free-ranging, and ubiquitous. Over the entire 1,956 square mile extent of the Northwest
Sands there is probably not a square inch of ground suitable for a cedar sprout that
is not easily accessible to a whitetail deer who will quickly munch it to oblivion.
The problem is so serious that some county forestry departments have instituted moratoriums
on harvesting white cedar until successful regeneration techniques can be found.
Unless humans intervene this important member of the wetland forest community faces
an uncertain future.
4) Project Area Habitat
Our cedar restoration project area is located in the Northwest Sands region of Wisconsin
within the St. Croix 
River watershed. Although this large area of sandy soils is often called
the sand or pine barrens it also contains many wetlands. The project area includes
30 acres of land that are enrolled in the Wisconsin's Managed Forest Law program.
One of our long-term objectives in land stewardship is the restoration of white cedar
on suitable mesic (moist) and forested wetland habitat.
Healthy wetlands are increasingly recognized for the key role they play in the environment.
As an important late successional member of the wetland forest community white cedar
should be restored to areas where it formerly grew. Not only is this species indigenous
to mesic areas and swamps of the Northwest Sands, but white cedar also has high aesthetic,
wildlife, ecological, biodiversity, and commercial values and benefits. Once established,
these pioneer trees will serve as a seed source should future conditions become more
favorable for natural reproduction of white cedar.
Potential habitat for white cedar on the project area is excellent. There is a mosaic
of river edge, floodplain, shrub carr, forested wetland, mesic intermediate zone,
and pine-oak uplands. The rich bio-diversity of the project area is demonstrated
in that of the 56 tree species found in Wisconsin, 22 of them (or nearly 40 percent)
have been identified growing naturally on these 30 acres. Bird, fish, herptile, and
mammal bio-diversity is equally rich.
Wetlands
on the property have an active groundwater flow with many visible seeps and springs
originating from surrounding mineral sand uplands. The wetland basin is part of an
extinct post-glacial lake now filled with well-decomposed peat. This peat is of near
neutral pH and ranges in thickness from a few inches near the edges of the basin
to several feet thick towards the basin's center.
Because the project area wetlands lie in embayments between sinuous low upland divides,
there is an extensive intermediate or mesic zone that offers near optimum conditions
for white cedar growth. Naturally occuring species in this mesic zone and in nearby
forested wetlands include: balsam fir, white and black spruce, white pine, black
ash, big-tooth aspen, musclewood, red maple, American elm, silver maple, bur oak,
paper birch, speckled alder, sphagnum moss, and many other mesic and wetland plants
and shrubs.
5) Historical Ecology
The
nearest known natural growth white cedar stand is located about three miles east
of the project area. This stand of mature trees is in a wetland setting within the
Northwest Sands regional landscape. All trees have grown above the deer browse line
and no reproduction has been noted. The presence of this cedar swamp demonstrates
that the species is indigenous to this part of the Northwest Sands.
In the past white cedar may have grown in the immediate project area. This information
was provided by the late Heinrich Steinhilpert, who came with his family to the Northwest
Sands in 1905 at age 12 to homestead and farm the land. Mr. Steinhilpert lived to
the ripe old age of 102 with sound mind and sharp memory. He was part of the early
homesteading wave into the pine barrens during the 1890-1910 period. These settlers
obtained the dubious honor and title of "jack pine farmers."
When specifically asked about white cedar growing in this vicinity, Mr. Steinhilpert
stated that they were indeed found in the swamps here early on, but that these mature
trees were harvested by landowners for fence posts or sold for cash income. Remains
of cedar-post and barbed wire fences have been encountered on this and surrounding
properties in what is now second growth red pine and oak forest.
With the cutting of these mature trees, white cedar was apparently eradicated in
the vicinity of the project area. Except for those planted here in recent years no
living cedar specimens have been encountered on this or surrounding properties to
date. Similar eradication of cedar from areas of former habitat is probably common
in other parts of the Northwest Sands and across northern Wisconsin in general.
6) The Cedar-Deer Relationship
While a popular animal with hunters and backyard feeder enthusiasts, overly abundant
deer are a destructive agent to the forest. Eating a wide 
variety of woody and herbaceous
plants, large deer populations have led to known declines in certain native plant
species (Rooney and Waller, 2003). Due to its high nutritional value as a winter
browse ration white cedar is eagerly sought out and consumed by deer.
While the effects of deer predation on white cedar is devastating, in the short term
it can also be unpredictable. Our own cedar plantings met with success for several
years with no fencing or other protection. Browsing was light or absent although
the local deer population was considerable and constant. We even began to think that
the deer problem had been exaggerated.
While we offer no firm explanation for this early low predation rate, our belief
is that these local deer did not have a history of browsing white cedar because it
is no longer an available food source in this vicinity. To back up that notion we
offer the similar example of a few small hemlock tree transplants (Tsuga canadensis)
also planted here. Hemlock is another preferred winter deer browse species, but one
not found normally growing on the Northwest Sands. Although our unprotected hemlocks
were growing next to badly deer browsed cedars the hemlocks remained untouched!
Perhaps deer can somewhat lose their insatiable "taste" for white cedar
if it is not available to them over several generations. Upon reintroduction to cedar
the smell and palatability may not be familiar. While deer may nibble they may not
browse the tree to destruction. But should this unusual situation occur it will probably
end badly as it did here. Whatever kept deer from consuming project trees showed
signs of ending during the winter of 2003-04 and became a huge problem in the winter
of 2004-05. After the gun hunting season ended and cold weather set in we noticed
heavy browsing of our plantings. During the second winter this included a previously
unheard of boldness of coming right up around buildings during the night to feed
on cedars growing there. Once discovered as a winter food source nothing but a barrier
(or a bullet) will save small cedars from severe set-back or worse.
Due
to the number and size of project cedar trees immediately fencing them was not a
practical option in the short term. For those trees growing in the vicinity of buildings
we improvised a system of pole, brush, and lumber barricades, applied scent repellents,
and chased deer off with loud noises.
Such efforts were somewhat effective but involved a great deal of effort and watchfulness
as nocturnal deer become extremely bold and will cross barriers they would never
attempt in the daytime. At night deer almost seem to become a different creature
with greatly increased predatory habits. We now experienced the deer menace first-hand
and found that it had not been exaggerated. On the contrary we were amazed at how
quickly a few predacious deer were able to strip young white cedars; transforming
lush evergreens into bare skeletons in just a few nights time.
Losses of outlying white cedars in more remote areas of the project area were heavy.
Once attuned to cedar as a food source, deer have a keen ability to seek it out and
rapidly strip trees of all green foliage. In fact, by the time we realized how significant
the problem had become outlying trees had suffered severe damage. Without sufficient
snow to conceal them not even the smallest cedars escaped harm.
7) Long Term Harm
Winter
deer browsing of young white cedars quickly becomes a long-term chronic problem.
Damage is not a mere pruning or clipping back of outside needles, but a complete
stripping of all green foliage within the deer's reach. The most vulnerable cedars
are those that have not grown above the height of feeding deer or the so-called browse
line. As deer can stand and reach to around 7 feet high, a cedar needs to be at least
twice that height before it can sustain itself. Sometimes cedars that are just reaching
or growing above the browse line are given special treatment when their top leader
is bitten or broken off.
Heavily browsed trees do not quickly bounce back. Even given care the next growing
season they recover just a small fraction of their former green growth. This begins
a chronic cycle of further damage during subsequent winters when these same trees
will likely be visited and browsed again. This time, 
however, with green foliage at
a minimum deer will now chew off and eat entire branches they had not molested during
the previous winter. After two or three winters of repeated browsing there will be
nothing left of the tree except a bare central trunk with a few badly gnawed branch
stubs.
While severe browsing will kill some trees, others tenaciously cling to life by continuing
to send out a few green sprouts each spring. But if deer are present during subsequent
winters (as they almost certainly will be) these badly browsed cedars will have little
chance of ever growing into normal trees and in time will probably perish.
While a serious problem, the ecological damage caused by large deer numbers is not
generally recognized by the public. Many land owners keep hunters off their property
and wish to protect and/or feed every poor little "Bambi" that ambles along.
Other land owners who do hunt purposely harvest only large antlered bucks and refuse
to shoot does or fawns in the belief that larger numbers of deer in general will
increase future trophy buck potential.
By some accounts the present deer herd in northern Wisconsin
is 10 times what it was in pre-settlement times. Natural predator pressure on deer
is light to non-existent in most areas. And while the DNR acknowledges that deer
populations are consistently higher than they should be, the deer herd continues
to increase (WDNR, 1998). Unless some catastrophic disease event intervenes or a
series of extremely harsh winters occur there seems little chance that the deer herd
will be significantly reduced any time soon. As a consequence the white cedar forest
component will continue to decline as existing stands age with no natural reproduction
taking place.
8) Low Point
Having
experienced first-hand the difficulty of white cedar re-establishment in the wild
the project came to a crossroads. Should it continue or be abandoned? It was sad
to see the previously lush and cheerful little cedars now badly gnawed down with
years of growth lost. Sad seeing them losing their struggle for life.
On the other hand there were positive results to consider. In spite of this setback
we still felt committed to the project's future. Continuing seemed like the right
thing to do. We had also learned a great deal about the proper techniques of growing
white cedar and had demonstrated that conditions here were excellent for cedar growth.
Luxuriant foliage and cone production proved it.
In addition, although many cedars had been badly chewed up, they continued to earn
their "tree of life" name by tenaciously hanging on to their green spark
of existence. There was something inspiring and admirable in this beautiful, adaptable
and extremely hardy tree. A hardiness that suggested damaged trees might yet be saved.
Also, from experimenting with various barrier and fencing options we had drawn some
conclusions. Commercial repellents or improvised scent barriers to keep deer away
could not be relied upon. Trying to hide or conceal trees didn't work either. While
somewhat effective, cut brush barriers were labor intensive and tended to decay and
settle under the weight of snow. The only really effective deer barrier was metal
fencing.
To continue the project meant that a drastic change in strategy would be necessary.
A strategy that included a strong fencing committment. But fencing would be an added
expense and due to the number of trees involved they could not all be protected in
the short term. Yet leaving damaged trees unprotected on wild sites was not an acceptable
option either. Without protection and additional care there was no chance they would
re-establish themselves as healthy trees or ever grow above the reach of predatory
deer.
9) Deer Exclosures
While bold nocturnal creatures, it turns out that deer are fairly easy to manage.
Unlike a black bear that will tear down a fence by brute force to reach a food source,
the whitetail will normally only jump over or slip through gaps. If used properly
fencing can be an effective means of protecting young cedar trees from deer predation.
In spite of the additional cost and labor fence barriers would have to play a significant
role in the project's future.
Having already experimented with various 
heights and fencing types we concluded that
14 gauge welded-wire fencing with 2x4 inch openings was a good compromise between
cost and durability. When made into circular upright tubes for placement around individual
trees, this grade of fence is strong enough to be self-supporting. This eliminates
the added expense and labor of buying and setting fence posts. If added stability
is desired the tube can be staked to the ground or some dirt heaped up around the
base. During the critical winter months ice and snow will further anchor it. As the
enclosed cedar tree grows larger inside the tube its branches will catch in the wire
openings and also hold the deer exclosure tube firmly in place.
These simple deer exclosures are easily fabricated by cutting off lengths of fencing
and then forming them into tubes by twisting the cut wire ends together. From measuring
browsed and unbrowsed trees we determined that the minimum size for such tubes should
be 4 feet in diameter and 5 feet tall. Deer cannot get their heads over a 5 foot
high fence and at this height the tree will be completely protected while it gains
stature. The 4 foot diameter is the smallest size for a self-supporting tube, but
one that still provides enough room for the cedar to grow adequately wide and bushy
during its shrub stage. A 4 foot diameter tube also has a small enough footprint
so deer will not jump inside of it. And while foliage growing through the wire openings
will be browsed off this should not significantly harm the tree and will provide
some sustenance for wintering deer. The 2x4 inch openings will keep out snowshoe
hares, that some sources claim are another cedar predator, although we have not experienced
rodents to be a problem at this time.
Another material for fabricating effective deer exclosure may be tubes formed from
steel reinforcement mesh used in concrete work. However, the 6x6 inch openings of
this mesh are considerably larger. This would allow hares to slip through and deer
to poke their snouts in a bit farther. However the cost of concrete reinforcement
mesh is somewhat less than 14 gauge welded wire fencing and consists of heavier 10
gauge wire that would provide a stronger self-supporting deer exclosure. Although
not galvanized, rust may not be a serious problem. In future we plan to experiment
with tubes made from this 10 gauge reinforcement mesh and compare its long-term performance
compared to tubes made from 14 gauge welded-wire fencing.
10) Recovery Nursery
As
mentioned, chronically over-browsed small cedars on wild sites need additional care
to recover. Fencing them as individuals may not be practical due to high up-front
costs, locations in partial shade, and competition for water and nutrients. Therefore,
a new technique was devised and adopted last fall. This entailed moving small damaged
trees from wild sites into a protected refuge where deer cannot reach them.
Fortunately we already had a large fenced-in yard and vegetable garden area. Although
it involved considerable time and effort we began digging up and transferring small
injured trees from the wild and into a nursery row inside the fenced garden area.
By freeze-up we had relocated some 25 trees in this manner. This coming spring we
will transplant the remaining 75 or more small trees still located on wild sites.
Inside the fenced nursery area these over-browsed trees will be tended and brought
back to healthy condition by regular applications of water and fertilizer. They also
will be growing in amended garden soil in full sunlight. There they will also be
safe from competition and predation.
Our estimate is that it will take these trees about two years to recover enough to
be transplanted back onto wild sites. That time interval will allow additional fencing
to be obtained for use as deer exclosures. As trees recover sufficiently they will
be transplanted back onto favorable wild sites. This time, however, each will receive
a deer exclosure for protection. Using this technique deer predation should be almost
totally eliminated from the tree's life cycle and a high success ratio is anticipated.
Unmolested, these protected trees will grow above the 7 foot deer browse line and
when they reach the self-sustaining height of around 15 feet the tube will be permanently
removed. At that time the exclosure will be used to protect another tree transplanted
to a wild site. Using this method the practical working life of these deer exclosures
should be almost unlimited. At least long enough for an older guy like me not to
see the end of their working life.
As exclosures are removed deer will be allowed to browse the lower branches and foliage.
So in the end the deer will get what they want anyway, but without destroying the
tree before it had a chance to establish itself. This will benefit not only deer,
but also the overall ecology. Once they have overcome the deer browsing menace, these
white cedar trees should have a long life possibly lasting hundreds of years as the
species has few disease or insect problems. Such a cedar restortation project seems
to be a case where human intervention and land stewardship can work hand-in-hand
with positive long-term environmental results.
11) Conclusion: Current Winter Conditions
As
this is written during the winter of 2006, we are experiencing a very mild winter
thus far. Snow cover is minimal and temperatures are above normal. An easy winter
means that deer numbers will increase even more.
Once again a system of improvised barriers was set up to protect trees growing near
buildings. Eight newly made welded-wire tube deer exclosures were placed around some
individual trees. Some of these trees will be transplanted to wild sites this spring
and given tube exclosures. Outlying browsed trees will be moved into the fenced refuge
area. So far this winter the only additional losses have been 2 small trees browsed
when deer slipped past our barriers.
With the new year comes a new optimism for the future. Hopefully given time and dedication
the "tree of life" will again grow on this richly diverse wetlands-barrens
complex on the Northwest Sands. It is a natural legacy that we hope will provide
positive ecological values and benefits for generations to come.
Spring Update:
6 March 2006.
With the help of the county DNR forester, we are applying to the Wisconsin Forest Landowner Grant Program (WFLGP). If approved, this Grant will assist us in obtaining material and setting deer exclosures for our White Cedar Restoration Project.
The DNR forester also suggested that we consider using somewhat larger exclosures for protecting several trees at once instead of just using individual exclosures.
After doing some calculating, this turns out to be a good idea. Depending on tree size we can protect three to six cedar trees at one time by using 9-foot diameter tubes. This size exclosure yields approximately a 20 percent savings in material over three 4-foot individual tubes and much more for six individual exclosures. If the Grant comes through in a timely manner, these larger tubes would eliminate the need for moving browsed trees into our protected garden area as they could be grouped and protected directly on wild sites. Grouped in this manner, these plantings will be easy to maintain. When these multiple tree groups begin to crowd each other, excess trees can be relocated until only three trees per exclosure remain. This appears to be a good revised strategy.
However, to remain self-supporting (we wish to avoid the added expense and labor of buying and setting fence posts), these larger exclosures should be fabricated from the heavier 10-gauge steel reinforcing mesh described above in paragraph #9. The 10-gauge mesh should present little problem and I have been increasingly leaning in that direction anyway over the lighter and more expensive 14-gauge welded wire fencing material. From one 150 foot roll of the 10-gauge material five exclosures of an even 30 foot circumference can be fabricated of just over 9-feet in diameter.
Yesterday, when I spoke to a local construction supply firm to get a price quote, the owner mentioned that this 10-gauge mesh is not galvanized and would show surface rust, but added that he thought it would still last "a hundred years." Good enough!
Although our DNR forester did not mention it, there is another reason why larger exclosures may have merit. As previously mentioned, the destructive browsing effect of deer on woodland community plants has been well-documented (Rooney, T.P. and D.M. Waller, 2003). By protecting somewhat larger areas we will be creating potential micro-refuges for other vulnerable plant species. Within exclosures we may observe regeneration of other browsed-to-oblivion native woodland plants. This would be another ecological benefit of the White Cedar Restoration Project. Hopefully the Grant will be approved and funded in the near future as without protective exclosures the Project has been brought to a screeching halt by the locally over-abundant and over-protected deer herd.
If you would like to learn more about the white cedar restoration project email me at:
herbswoods@yahoo.com
Return to: Herb's Woods
White Cedar Reference Notes
Burns, Russell M., and Barbara H. Honkala, 1990. Silvics of North America: Vol 1.
Conifers; Agriculture Handbook 654. U.S. Department of Agriculture, Forest Service,
Washington, DC.
Davis, Alaina. Klaus Puettmann, and Don Perala, 1998. Site Preparation Treatments
and Browse Protection Affect Establishment and Growth of Northern White-Cedar. Research
Paper NC-33. USDA Forest Service, North Central Forest Experiment Station: St. Paul,
Minn.
Giizhik (northern white cedar) in the Ceded Territories. Great Lakes Indian Fish & Wildlife Commission
Hoff, Mary, 2000. Can We Save Upland Northern White Cedar? Minnesota Plant Press
20(1)
Johnston, William F., 1977. Manager's Handbook for Northern White Cedar in the North
Central States. General Techical Report NC-35. USDA Forest Service. North Central
Forest Experiment Station: St. Paul, Minn.
Kahler Kathryan A., 2005. Vertically Inclined: A forest of ancient twisted trees
grows from the cliffs of the Niagara Escarpment. Wisconsin Natural Resources (December
issue).
Miller, Raymond O., 1990. Ecology and Management of Northern
White-Cedar. Paper presented at the Regenerating Conifer Cover in Deer Yards workshop.
North Bay, Ontario Canada.
Peattie, Donald Culross, 1991. A Natural History of Trees. Houghton Mifflin Co.,
Boston, Mass., USA.
Rooney T.P., S.L. Solheim, and D.M. Waller, 2002. Factors Influencing the Regeneration
of Northern White Cedar in Lowland Forests of the Upper Great Lakes region, USA.
Forest Ecology and Management 163: 119-130.
Rooney, T.P. and D.M. Waller, 2003. Direct and Indirect Effects of Deer in Forest
Ecosystems. Forest Ecology and Management 181: 165-176.
Steinhilpert, Heinrich. Interviews with author. Various dates, 1980s.
Wisconsin Department of Natural Resources, 1998. Wisconsin's Deer Management Program.
Second Edition. Pub. SS-931-98. Madison, WI
Wisconsin Department of Natural Resources, 1999. "Northwest Sands," Ecological
Landscapes of Wisconsin. Madison, WI
Wisconsin Department of Natural Resources. Siviculture and Forest Aesthetics Handbook
HB 2431.5. Madison, WI
Copyright 2006 Herbert Wagner
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