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A Field Survey of Woody Species in the
Jensen Landscape of the
Henry Ford Estate.
University of Michigan-Dearborn
Gerard Heath
Wayne Roper
Orin G. Gelderloos
(faculty advisor)
Location of University of Michigan-Dearborn
and Henry Ford Estate
Location of University of Michigan-Dearborn
and Henry Ford Estate
The Henry Ford Estate is
surrounded by a highly
urbanized area.
To the East are shopping
centers and to the West is a
golf course and densely
populated housing.
The presence and preservation
of the Henry Ford Estate is
significant to native species of
plants and animals.
Ironically, the Estate was commissioned by Henry Ford in 1914
as a way for him to reside in an area removed from the
expanding urban landscape and for he and his wife, Clara, to
have a place to enjoy their love of nature.
Jens Jensen
When Henry Ford decided to convert the former
farmland to his new estate he commissioned the
work of landscape architect Jens Jensen.
His designs typically incorporated loose openings
such as narrow meadows and paths within dense
mesic woodlands.
The plan was initiated in 1915 and was completed
over the course of several years.
Trees in the new landscape were both seed grown
and transferred from other sites.
Jensen strongly believed in the ability of native plants and natural landscapes to
sustain wildlife and habitat.
Native plants are more likely to interact with each other, support native animal
species, and be adapted to local environmental conditions (climate, pests, etc).
Jensen's Meadow and the Rose
Garden in the middle of the
landscape
Aerial Photo of Henry Ford Estate
Image courtesy of Google Maps software
Aerial Photo of surveyed area
Trees Prescribed in Jensen's Original Plan
> Sugar Maple
> Red Maple
> American Beech
> Blue Beech
> White Oak
> Red Oak
> White Ash
> Red Ash
> Hophornbeam (Ironwood)
> Sycamore
> Black Walnut
> Basswood (Linden)
> Hawthorn (Haw)
> Juneberry
> Flowering Dogwood
> Sourgum
> Tamarack
> Butternut
Purpose of the Study
> To compare the original prescribed vegetation composition of the
Jensen landscape with the current vegetation and determine how the
Jensen plan has fared for nearly 100 years.
> We analyzed the species composition by dominant overstory
subdominant overstory, and understory trees by: species, number of
stems, and calculated basal area.
> What may the future be
for the Henry Ford Estate
and Jensen's landscape?
Methods
>
Identify and measure each tree encountered with a diameter breast
height (dbh) greater than 1.5 cm or circumference of about 5 cm. Dbh
identified at 4 ft.
>
Record data in the field by species and circumference within each
map area
>
Use circumference to find diameter and estimated basal area of each
identified tree
>
Survey period: September 2011 – December 2011
Results of 2011 field survey
58 species identified
3487 stems counted
Dominant Overstory
- Stems Identified:
- Total basal area:
(Trees with dbh >20cm)
463
865,546 cmsq
Sub-dominant Overstory (Trees with dbh 9.1 cm – 20 cm)
- Stems identified
447
- Total basal area:
66,127 cmsq
Understory
- Stems Identified:
- Total basal area:
(Woody vegetation with dbh <9 cm)
2577
34,166 cmsq
Common Buckthorn
Boxelder
H oneys uckle
Black Cherr y
Silver Maple
W hite As h
Amer ican Bladder nut
Staghorn Sumac
W itch-hazel
Cher ry s p.
H ighbus h Cr anberr y
Amer ican Elm
Redbud
Sugar M aple
H ackberry
Red M aple
H ophornbeam
Red Oak
Chokecherr y
Red M ulber ry
Flower ing D ogwood
Species Ranked by Total Number of Stems
Black W alnut
Cher ry s p.
H awthorn
Ar rowwood Viburnum
D ogwood
Black Locus t
Bas s wood
Ar rowwood Viburnum
Pr ivet
Shagbark Hickory
G ray Dogwood
W ild Crab
Cor nelian Cherr y
Os age-Or ange
Tulip Tree
Amer ican Beech
Cocks pur H awthor n
Blue Beech
Tree-of-H eaven
Eas ter n H emlock
Amer ican Bas s wood
Sas s afr as
Red-ber ried Elder
Eas ter n Cot tonwood
W inged Euonymus
Paper Birch
H ighbus h Cr anberr y
W hite Oak
H oney Locus t
Spicebus h
Pin Oak
Kentucky Coffee Tree
Kous a D ogwood
Slippery Elm
Lilac
Sycamor e
Eas ter n W hite Pine
M agnolia
Red A s h
Akebia
Black M aple
0
100
200
300
400
Number of Stems
500
600
700
Silver Maple
Red Oak
Red Maple
American Elm
Red Mulberry
Black Walnut
Sugar Maple
Basswood
Eastern Cottonwood
White Oak
Jensen Landscape Dominant Overstory Composition (dbh >20 cm)
(Ranked by number of stems)
American Beech
Common Buckthorn
Honeysuckle
White Ash
Flowering Dogwood
Hawthorn
Blue Beech
0
10
20
30
40
50
Number of Stems
60
70
80
90
American Elm
Silver Maple
Red Maple
Red Mulberry
Black Walnut
Sugar Maple
Hawthorn
Basswood
Common Buckthorn
Flowering Dogwood
White Ash
Blue Beech
White Oak
Jensen Landscape Sub-dominant Overstory Composition (dbh 9-20 cm)
Ranked by Number of Stems
Honeysuckle
Red Oak
American Beech
Eastern Cottonwood
0
5
10
15
20
25
30
Number of Stems
Figure 4: Jensen Landscape Subdominant Overstory Composition (9-20cm diameter)
35
Common Buckthorn
Honeysuckle
White Ash
Sugar Maple
Flowering Dogwood
Silver Maple
American Elm
Hawthorn
Red Mulberry
Red Oak
Black Walnut
Red Maple
Jensen Landscape Understory Composition (dbh 9-20 cm)
Ranked by Number of Stems
Basswood
Blue Beech
American Beech
Eastern Cottonwood
White Oak
0
100
200
300
400
Number of Stems
500
600
Figure 5: Jensen Landscape Understory Composition (<9cm diameter)
700
Observations of number of stems
The species with the greatest number of stems are part of the
understory.
- Common buckthorn
- American Bladdernut
- Honeysuckle
- Staghorn Sumac
- Witch-Hazel
Common Buckthorn has a relatively large number of stems
compared to other species in the same area (~ 16% of total
and ~ 22% of understory)
Observations of Basal Area
The top 5 species contribute to more than 50 percent of the
basal area but account for less than 10% of the number of
stems in the surveyed landscape.
Each of the species with the most basal area are typical of a
mature forest in the Michigan region.
A few species are prominent in both basal area and number
of stems
- Boxelder Maple
- Black Cherry
- Silver Maple
Trees featured in Jensen's original plan
FOUND
> Sugar Maple
> Red Maple
> American Beech
> Blue Beech
> White Oak
> Red Oak
> White Ash
> Red Ash
> Hophornbeam (Ironwood)
> Sycamore
> Black Walnut
> Basswood (Linden)
> Hawthorn (Haw)
> Juneberry
> Flowering Dogwood
NOT FOUND
> Sourgum
> Tamarack
> Butternut
Why are other prescribed species not present?
> Not able to transplant enough trees from surrounding
forests at the time
> Sourgum and Butternut can be found in other areas
throughout the estate, but may have been out-competed
in the Jensen landscape.
> Tamarack prefers more acidic soil. Not a great
competitor in this area.
44 of the identified species are not in
Jensen's original plan
How did new species get into Jensen Landscape?
>
Many birds and mammals eat fruits and transfer the seeds to the area
>
Wind dispersal of seeds
> Jensen encouraged ecological succession. New species were going to end
up in the area.
>
Some ornamental species planted since the original landscaping
Jensen's Plan
The species composition of the The Jensen Landscape is mostly
consistent with what is expected of a mesic forest.
The presence of large hardwood trees like maples, oaks, and elms
that prefer moist soil is evidence that Jensen's original plan for
native plants to thrive and provide habitat for other species has
worked.
Although Jensen's plan has lasted for almost a century, forests are
not static communities. Forests and meadows can be disturbed by
invasive species, pest infestations, human traffic, and other
damaging environmental factors.
Are there patterns in the inventory data that show any
possible trends?
Future of Jensen landscape:
Current Understory Species
Buckthorn, the infamous invasive species, appears to be populating the
forest understory.
Along with other weedy growth species like Honeysuckle and American
Bladdernut, Buckthorn can take over the forest understory and prevent the
reestablishment of larger native species like maples and oaks which are
expected to repopulate the forest floor
Future of Jensen landscape:
Current Understory Species
Birds are eating Buckthorn fruit and spreading the seed throughout the
landscape, and there are not any species helping limit Buckthorn
population growth. Management of Buckthorn population may have to
be done by hand or with the introduction of a biological control to
establish a balancing force against Buckthorn dominance of the
understory.
Seeds found in droppings of American Robin (T. migratorius) and Gray Catbird (D.
carolinensis). Research by Julie Craves and Dana Wloch, UM-Dearborn.
Future of Jensen landscape:
Current Understory Species
While surveying trees there were many
stands of American Bladdernut which had
not yet reached the 1.5 cm dbh qualification.
In the years to come those stands of
Bladdernut may become dense enough to
crowd out the area and prevent new
saplings from growing
Mature White Ash trees in the Jensen
landscape had previously been
decimated by the Emerald Ash Borer
(Agrilus planipennis). A foreign pest
that is relentless in its attacks. Perhaps
the Ash saplings arise after mature
Ash trees topple over and create
openings for sunlight in the high
canopy.
Understory species in the Jensen landscape
Nearly a century later
Despite the presence of over 130 stems of
White Ash, the future of the species in the
area is bleak. To learn new ways to prevent
Emerald Ash Borer attacks or to prevent Ash
saplings from the same fate as mature trees,
it is in the best interest of preservation to
closely monitor and protect any young Ash
trees to help maintain the composition of the
mesic forest and meadows that Jensen
planned many years ago.
www.markleyspest.com
Other large tree species like Maple and Oak appear to have healthy
mature populations, but their understory populations pale in
comparison to other . There is little cause for concern about the older
trees, but saplings will need to compete with invasives and weeds.
What should be done?
Miraculously, Jensen's native landscape plan has survived
through decades of surrounding urbanization, possibly because
of the connection to Henry Ford's name and the desire to
preserve his legacy.
Almost a century later we can confirm that the composition of
the landscape is that of a mesic forest. Most of Jensen's initially
planted species are present and only a few did not survive to
populate the estate grounds. His plan was fulfilled, but could
possibly be in danger because of invasive species.
What should be done?
The Heny Ford Estate is one
of few natural areas
remaining in Southeast
Michigan.
The reasons to ensure the
health and longevity of the
area we have inventoried
are both ecological and
ethical. There is little native
habitat remaining to support
wild animals and provide a
natural buffer against urban
activity.