Forest Stewardship Spatial Analysis Project
Michigan Methodology
March, 2007
Project Summary
The Spatial Analysis Project (SAP) was created as a means for each State to
determine their Forest Stewardship needs, focuses, goals, etc. while still allowing a
consistent look at all States combined. The U.S. Forest Service identified 12 key factors
that could be used to assist in the identification of lands with ‘Stewardship Potential’.
These factors were separated into two subgroups; Resource Richness and Resource
Threats.
The Resource Richness factors include:
Private Forest Land
Forest Patch Size
River Corridors
Priority Watersheds
Proximity to Public Lands
Wetlands
Natural Heritage
Public Drinking Water
Slope
The Resource Threat factors include:
Forest Health
Development Level
Wildfire Assessment
Each State determines what weights should be applied to each factor so that it is
most appropriate for the State’s needs, focuses, and goals for Forest Stewardship
management, protection, conservation, and sustainability.
Michigan’s assessment of the weights for these 12 factors was determined
through the Forest Stewardship Advisory Committee which includes a combination of
State employees, private land owners, timber industry employees, etc. Each attendee was
given 10 sticker dots. They were then instructed to place the dots on the factors they
believed to be the most significant or highest priority. Each person could place more than
one dot on any of the factors. After analysis of each factor it was determined that the
following weights would be applied out of a total of 100 where 100 is the highest
possible value;
Slope – 0.82 (Slope not considered a influential factor for the State of Michigan)
Public Drinking Water – 1.22 (Prevalent drinking water supplies)
Wildfire Assessment – 2.85 (Wildfire not considered all that threatening of a factor)
Natural Heritage – 6.94
Developing Areas – 7.76
Wetlands – 7.76
Proximity to Public Lands – 8.16
Priority Watersheds – 8.57
River Corridors – 11.02
Forest Health – 12.24
Forest Patch Size – 14.29
Private Forest Lands – 18.37
Areas of land that were either publicly owned or had a land cover/land use
classification of open water or urban were excluded from consideration as those areas are
not within the scope of the Forest Stewardship program and there is no Forest
Stewardship Potential in those areas.
A Jenks Natural Breaks classification algorithm was used to differentiate the
values into low, medium, and high classes. This allows for classes to be created based on
natural groupings and breaks in the data values.
Forest Stewardship Potential Weighted Composite
Stewardship Potential
Low
Medium
High
Areas without
Stewardship Potential
Forest Stewardship Methodology
Private Forest Lands: Private lands were derived from subtracting public lands from
entire State of Michigan boundary. The statewide forested lands were derived from the
2001 Land Cover data. The 2001 Land Cover dataset is specific to the State of Michigan
and was created from Landsat Thematic Mapper 30 meter resolution satellite imagery,
the National Oceanic and Atmospheric Administration’s Coastal Change Analysis
Program, and incorporating the Forest Inventory and Analysis data to verify the accuracy
of land cover types. The privately owned lands were then overlaid with the forested land
to determine what areas were privately owned forest lands.
The level three land cover types used for the forest land area were; Low Density
Trees/Upland Shrub, Northland Hardwood, Oak Types, Aspen Types, Other Upland
Deciduous, Mixed Upland Deciduous, Planted Pines, Natural Pines, Other Upland
Conifers, Mixed Upland Conifers, Upland Mixed Forest, Lowland Deciduous Forest,
Lowland Coniferous Forest, Lowland Mixed Forest, Floating Aquatic, Lowland Shrub,
Emergent Wetland, and Mixed Non-forest Wetland.
Forest Patch Size: Forest patch size was developed from contiguous forest areas derived
from the 2001 Land Cover data. The same cover types were used for this analysis as
what was used for the private forest lands. After much consideration, it was determined
to use a consistent value of greater than 500 acres statewide. It is believed that this value
will allow for effective forest and wildlife management practices to be considered and
practiced. The State of Michigan has a vast contiguous forested area in the Upper
Peninsula and the Northern Lower Peninsula. Some of the islands in the State of
Michigan have more contiguous or equally as contiguous forest land as the Upper
Peninsula and Lower Peninsula, but because they are smaller in size, would be excluded
from consideration if a larger acreage value was used. We believe that these islands are
equally as important as the inland parts of the State, so a smaller acreage value was used
to include those islands for Forest Stewardship Analysis.
We will look into using other data that incorporates patchiness as a measure of
patch size with an isolated area or adjacent to other forest patches once the data is
complete and available.
Forest Health: Both pests and diseases were used from the 2006 Forest Health data from
the U.S. Department of Agriculture along with the Michigan Emerald Ash Borer data.
The pests and diseases that were considered were; Aspen Leafminer, Beech Bark
Disease, Emerald Ash Borer, Forest Tent Caterpillar, Gypsy Moth, Jack Pine Budworm,
Larch Needle Blight, Oak Skeletonizer, Oak Wilt, and Spruce Budworm.
River Corridor (Riparian Corridor): The perennial rivers and streams were selected from
Michigan’s rivers and streams from the ESRI Data and Maps U.S. Rivers & Streams
dataset. A distance of 100 feet, as determined by the Forest Stewardship Advisory
Committee, was used to create a buffer on both sides of the perennial rivers and streams.
This distance is believed to include vegetative and habitat significance along the river
edges. No official Riparian Corridor feature class exists at this time for the State of
Michigan. To prevent concerns for riparian area management, it was determined to avoid
using the term riparian until such an official dataset does exist.
Priority Watersheds: Watersheds with either Michigan Department of Natural Resources
designated Natural Rivers or U.S. Forest Service designated Wild & Scenic River
systems included in the watersheds were considered higher priority. The U.S. Geological
Survey National Hydraulic Dataset was used for the watershed boundaries.
Proximity to Public Land: All privately owned lands within a distance of one-half mile
from public lands (Local, County, State, or Federally owned land) were given greater
weight. The federal, county, and locally owned land was derived from the GAP
Stewardship dataset created by The Nature Conservancy. The state owned land dataset
managed by the Michigan Department of Natural Resources was merged with the other
public ownership data.
Wetlands: All areas designated as Riverine, Lacustrine, and Palustrine systems from the
digital National Wetlands Inventory dataset created by the U.S. Fish and Wildlife Service
were included in this dataset.
Developing Areas: The housing density dataset from the 2000 U.S. Census Bureau and
the derived 2030 year data, as developed by Dr. David M. Theobald from Colorado State
University, were used to create this dataset. The 2030 year data was completed by using
the U.S. Census Bureau data, county level population forecasts, transportation networks,
existing land cover types, etc. The areas designated as undeveloped, rural, or exurban in
the 2000 year data that will change to suburban or urban in the 2030 year data are the
areas believed to be of greatest concern for future development.
Natural Heritage: The most recent and accurate threatened and endangered species data
was derived from the Michigan Natural Features Inventory’s Element Occurrences
database. Specifically, only the plant, animal, and community types were selected (i.e.
‘other’, geographic features, was not included). Only features with the highest precision
for location and a last observation date since 1949 were included in this dataset.
Wildfire Assessment: The Lake States Wildfire Data created by Dr. David T. Cleland
was used. Only the areas designated as crown, very high surface, and high surface were
considered as high risk fire areas. Although the Southern Lower Peninsula of the State of
Michigan is not included in Dr. Cleland’s work, it has been determined by the Michigan
Department of Natural Resources’ fire specialists that the areas excluded are not high
wildfire risk areas. These areas fall in mostly urban or agricultural cover types with few
large forest areas available for the spread of forest fire or wildfire. Also, there are far
more fire response stations and better road networks for fire response so that in the event
a fire does break out, it can be easily and quickly extinguished.
Public Drinking Water: Groundwater Recharge data created by the Michigan Department
of Environmental Quality, U.S. Geological Survey, and Michigan State University was
used to determine areas of highest groundwater recharge capacity as a means to protect
those areas. The areas with a calculated groundwater recharge capacity of 14 to 22 (22 is
highest level in the State of Michigan) inches per year were the only areas included in
this dataset.
Slope: Areas with a slope of 33 percent and higher were used for this dataset. 33% is the
slope percent for critical dunes that is considered unstable and/or vulnerable to erosion.
Slope percents that are more specific to soil types, moisture levels, etc. may be developed
and used in the future. The slope data was derived from the U.S. Geological Survey
Digital Elevation Model, 30 meter resolution data.
Once all datasets were queried out based on the desired criteria, they were all
converted to an ESRI GRID format with a cell size of 30 meters. The cell values were
given either a ‘1’ where the data does exist or a ‘0’ where no data exists. A conditional
addition map algebra expression was completed that applied the appropriate weights to
each dataset. The areas to be excluded were given zero values to eliminate them from
consideration. The final values ranged from 0 to 97.96 where 100 is the highest value
possible.
Using the Jenks Natural Breaks classification algorithm the cells were divided
into three classes Low, Medium, and High. The classification groups are as follows; Low
= 0 – 21.52, Medium = 21.52 – 45.80, High = 45.80 – 97.96.
Because the State of Michigan has two peninsulas which tend to be considerably
different in primary land cover types, contiguous forest cover, as well as forest cover
types, particular interest existed in the Forest Stewardship Potential values for each
peninsula as well as how many acres exist for each of the three class levels (Low,
Medium, and High). Because the Lower Peninsula is far more fragmented and has more
land cover types across the landscape, it was initially believed that the Upper Peninsula
would have higher values and have far more acres of High Forest Stewardship Potential.
Although there are more total land acres in the Lower Peninsula, the acreage
totals for the High Forest Stewardship Potential in the Upper and Lower Peninsulas was
about equal. This is of particular interest regarding the weighting scheme used as it
appears that the weights used did effectively capture lands in both peninsulas equally.
Listed below are the values for each of the three levels (Low, Medium, and High) for the
peninsulas individually for only the Forested Land areas. Non-forested land was not
considered in this analysis because most of the non-forested areas are not in the High
Forest Stewardship Potential areas.
Private Forested Land Upper
Peninsula
Low
Medium
High
Acres
36,339.43
3,070,153.41
2,345,111.59
Total Private Forested Land
Low
Medium
High
Acres
1,067,513.81
8,512,708.28
5,040,279.02
Percent Upper Peninsula
Private Forest of Total
Low
Medium
High
3%
36%
47%
Private Forested Land Lower
Peninsula
Low
Medium
High
Percent Lower Peninsula
Private Forest of Total
Low
Medium
High
Acres
1,031,174.38
5,442,554.87
2,695,167.43
97%
64%
53%