Transcript Slide 1

A LOW COST DEER EXCLUSION APPROACH
FOR FORESTED RIPARIAN BUFFER PLANTINGS
W. Neil Gillies
Frank Rodgers
Cacapon Institute
High View, WV
It is not the number of trees planted but the
number of trees we grow that will restore
our forests and protect our waters.
The Lab and other partners on the Hampshire County Riparian Buffers
Task Force developed this riparian buffer demonstration project in 1995.
They did a good job with the planting, and no trees survived – despite
repeated attempts.
In 2005 we helped replant the Yellow Spring site, this time using tree tubes.
This was one of the first two WV Potomac Tributary Strategy Implementation
Team demonstration projects, and was funded by the Chesapeake Bay Program.
Trees were planted in 2’ and 4’ tubes by a WV CREP contractor.
13 species were
planted.
Species
Planted
Yellow
Spring
White Ash
15
Shagbark
Hickory
15
Sugar Maple
15
Northern Red
Oak
15
White Oak
15
Yellow Poplar
20
Black Walnut
15
Crabapple
35
Buttonbush
35
Washington
Hawthorne
35
Hazelnut
35
Flowering
Dogwood
35
Chinese
Chestnut
35
Total Count
320
We even put up a new sign.
Now that the trees were in tubes,
how did the plantings fare?
Deer browsing was a huge problem!
Yellow Spring - Browse
100%
75%
50%
25%
0%
July
2005
June
2006
Not Browsed
Sept
2006
Browsed
Yellow Spring - Survival
100%
75%
50%
After two years, only a few scraggly Hawthornes and
crabapples were growing much past the top of the tubes,
every plant that could be browsed was, and survival was
dropping fast.
25%
0%
July
2005
Leaf
June
2006
Sept
2006
No Leaf
How can you have successful riparian plantings
in areas with abundant deer at a reasonable cost?
I started a backyard experiment in 2006
testing the use of parallel electric wires run
through a riparian zone in a very high deer
area. Initial results were very promising.
Trees planted without tubes were not
browsed. Natural recruitment was observed.
No unprotected trees outside the
fenced area that are < 7’ high
survive on this 54 acre property.
Based on the early success of this backyard experiment, WVDEP
provided us with a small grant to do pilot trials on two study sites.
The first site was the Yellow Spring riparian site, set up in May 2007. It had
two experimental blocks with three wire perimeters, two control blocks with a
single electric wire running along one side, and one control block with no
electric wires. All blocks were 60’ x 100’. Power was from a solar charger.
All of the trees at this site (that had grown to the top of their tube)
had been browsed repeatedly over the previous two years. Many
were quite weak.
We replaced a number of the dead trees in each study block
with chestnut oak, ash, silky dogwoods and persimmons in
May 2007 . . . in 1’ tubes for rodent protection.
C
on
tr
C ol n
on o
t
w
C rol ire
on n
o J
C tro w un
on l
ir
e
tr no e J 07
w ul
C ol
on no ire y
C tro w A 07
on l
ir u
tr no e S g 0
ol
w e 7
no ire pt
w M 07
C
ire ay
on
tr
Ju 08
ne
C ol w
on
08
tr / w
C o l ir e
on w
J
C tro / w un
on l
ir e
t r w/ e J 0 7
C ol wi uly
on w r e
0
C tro / wi Au 7
on l
r
g
t r w/ e S 0 7
ol w e
w ir e p t
/ w M 07
ir
Ex
e ay
Ju 08
pe
ne
rim
Ex
08
e
pe nt
a
r
Ex im l J
p en un
Ex erim ta e 0
p e e l Ju 7
n
Ex rim tal ly 0
A 7
p e
Ex eri nta ug
pe me l S 07
rim nt ep
a
en l M t 07
ta ay
lJ
un 08
e
08
Percent of Trees
Yellow Spring Results
Yellow Spring Site
No-Damage
Uncertain
Browse Damage
100%
80%
60%
40%
20%
0%
Browse damage in Experimental plots in August 2007 was probably due to heavy
weed growth that reduced voltage on the electric fence to less than 2500V.
Experimental
Silky Dogwood
Hazelnut
June 6, 2008
June 6, 2008
May 2007
May 2007
Experimental
Sugar
Maple
Hawthorne
June 6, 2008
June 6, 2008
May 2007
May 2007
Control
Hazelnut
Hawthorne
June 6, 2008
June 6, 2008
May 2007
May 2007
Yellow Spring Results
Median height of highest intact leaf above tube.
Median Height above Tube Results
Excluding Hawthorne
Height above Tube
2.5
Jun-07
Jul-07
Aug-07
Sep-07
May-08
Jun-08
2
1.5
1
0.5
0
NCB
SCB
NCBNW
Control Sites
Site
SEB
NEB
Experimental Sites
Yellow Spring Results
Sample size of plants with intact leaves above tube.
Sample Size Leaves above Tube
Excluding Hawthorne
Jun-07
35
Jul-07
Aug-07
Sep-07
May-08
Jun-08
Number above Tube
30
25
20
15
10
5
0
NCB
SCB
Control Sites
NCBNW
Site
NEB
SEB
Experimental Sites
Site 2 is a USDA-CREP (Conservation Reserve and Enhancement
Program) site near Baker, WV. Forest condition in the area and the landowner
indicated a deer problem exists. This area was planted and a high tensile, electric
cattle fence installed in the spring of 2007 under CREP. The two control and two
experimental test blocks are 100 feet long and ~35 feet wide, the standard buffer
width in WV. There are two perimeter wires spaced four feet apart. Fence was
initially powered via a tap from the high tensile fencing.
There were problems at Site 2:
•Early browsing in experimental plots led to discovery
that CREP fence powering the site had insufficient
voltage (<2500V)
•Installed solar fence charger for test blocks in July
2007, but still had some browsing in early August 2007.
Discovered a short in fence that reduced voltage to
~2200V. Sigh.
•Fixed short, voltage >5000, browsing problem
eliminated in September 2007.
•Vegetation got ahead of us in June 2008, fence voltage
down below 3000V.
•All of the above issues led to “training to the fence”
inconsistency.
•Despite the problems, how did the plants fare?
on
tr
ol
07
e
M
ay
08
08
ep
t0
7
ug
Ju
n
on
tr
ol
S
A
07
07
Baker CREP Site
Ex
pe
ri
m
en
ta
lJ
Ex
un
pe
e
07
ri
m
en
ta
lJ
Ex
ul
pe
y
ri
07
m
en
ta
lA
Ex
ug
pe
ri
07
m
en
ta
lS
Ex
ep
pe
t0
ri
7
m
en
ta
lM
Ex
pe
ay
ri
08
m
en
ta
lJ
un
e
08
C
on
tr
ol
on
tr
ol
C
C
C
e
Ju
ly
Ju
n
on
tr
ol
on
tr
ol
C
C
Percent of Trees
CREP Site Results
No-Damage
Browse Damage
Uncertain
Below Tube Top
100%
75%
50%
25%
0%
May 2007
June 26, 2008
Inside exclosure
Outside exclosure
Experimental Block East
Experimental Block West
Control Block West
Control Block East
Bears Hell Results
Median height of highest intact leaf above tube.
Median Height Above Tube
7/20/2007
Height Above Tube (ft)
2
8/11/2007
9/19/2007
5/26/2008
6/23/2008
1.5
1
0.5
0
ECB
Control Sites
WCB
EEB
Site
WEB
Experimental Sites
Bears Hell Results
Sample size of plants with intact leaves above tube.
Sample Size Leaves Above Tube
7/20/2007
No. with Leaves Above Tube
50
8/11/2007
9/19/2007
5/26/2008
6/23/2008
40
30
20
10
0
ECB
WCB
Control Sites
EEB
Site
WEB
Experimental Sites
Estimated Material Costs per Acre
Area
Fence
Tubes and stakes
One acre
$
668
$
758
Two acres
$
1,045
$
1,516
Three acres
$
1,423
$
2,274
Four acres
$
1,800
$
3,032
Notes:
1. assume weed mats used for each setting
2. Retail prices for materials
3. Tree tube stakes are estimated, probably cost more.
4. Assume 2-wire perimeter fence installed with temporary
fence materials.
How is my “backyard” experiment doing?
•A significant amount of natural recruitment has taken place,
including: black walnut, witch hazel, hornbeam, hophornbeam,
linden, red maple, oak spps, hickory, dogwood, cherry, ash, box
elder, tulip poplar, locust.
•There have been only two plants slightly browsed in two years.
•Every tree outside the fence exclosures is heavily browsed.
•Three non-tubed plants were lost overwinter to vole damage.
•Lack of browse = potential for proper forest structure below 6 ft.
Here is a summary of what we observed between June 2007
and June 2008:
• If the fence is properly installed, energized, and clear of heavy
weed growth, protection within fenced areas can be ~100%.
•In the first few weeks after installation, check the fence for
damage as the deer get very upset when they first get in it. The
inner wire is more likely to be broken than the outer wire.
•There does not appear to be much of an edge effect (if any)
where trees near the fenced area are protected.
•Failure to maintain the fence reasonably clear of heavy weed
growth results in lowered voltage on the fence and, over time,
dramatically reduced success.
•Just as the literature says, voltages in the 2000-2500 voltage
range are not terribly effective against deer.
•The fencing sadly doesn’t protect against drought, insects, or
rodents.
A local landowner used our fence design on their planting project.
“We are going ahead with the planting this weekend and installing two fenced
areas according to your specifications on "site 1" of your study for the walnut
planting here at the farm. One of the plots is about 360ft x 30ft and another is
about 250ft by 180ft. . . . The trees that will be within the perimeter of the fence
are going to have to fare without tree tubes.” (Fall 2007)
June 2008: “Our trees are . . . doing very well. We have two plantings. The
one on a hillside has been easy to access and is mown regularly. The
other planting was underwater for some time this spring and the grass
got away from us while we could not get to it with the little mower.
I am not sure how those trees are doing at the moment.
The maintenance has been the major downside, we have had to mow
with a garden mower and the tractor took out the outside strand at
one point this spring. Fortunately, repair is easy. Other than
maintenance, we are very pleased with the very high survival rate and
healthy growth of the trees.
Louise McDonald
The Bower Farm
We have a National Fish and Wildlife
Foundation grant to expand this project to
other riparian sites, and also to upland forest
settings, in the Chesapeake Bay watershed.
We are looking for cooperators to help select
suitable sites and participate in the project by
by performing routine maintenance.
Please let me know if you are interested.
When white tail deer are too abundant, both the understory and the
forest floor layers become degraded, sometimes severely.
The understory becomes thin, with few or no new seedlings given a
chance to grow, and few leaves left below the deer browse height.
The accumulation of fallen leaves that forms much of the litter layer
on the forest floor can largely disappear.
The role that a thick bed of decaying leaves and good forest soil
structure play in slowing runoff, storing moisture, and cycling
nutrients may be diminished as a result. If true, this would lead to
drier hillsides, more erosive runoff, less infiltration (less
groundwater recharge), and flashier streams that dry up easily.
Thanks to the National Fish and Wildlife Foundation grant, CI is
starting a long-term study to determine if exclusion of deer from
sections of forest leads, over time, to an increase in leaf litter
retention, restoration of a healthy forest soil structure, and an
increase in retained moisture.
It is not the number of trees planted but the number of trees
we grow that will restore our forests and protect our waters.
Any questions?
Cacapon Institute at www.cacaponinstitute.org