ELC – Day 3
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Polygon Identification & Delineation
Vegetation Sampling and Description
Vegetation Classification
Field Work
Polygon
Concepts
Goals and objectives
will determine:
• scale
• polygon size
• degree of
heterogeneity you
need to deal with
• intensity of
sampling - time
ELC
Ecosystem
mapping
1
The Concept of a Polygon
• Polygons are discrete
areas that are outlined
on a map or air photo
that contain more or
less homogenous site
conditions that visibly
differ from the adjacent
landscape matrix
• Polygons are typically
irregular in shape;
however in S. Ontario
they tend to be
geometric due to
adjacent land uses
Polygon Scales
increasing
complexity and
work
Polygons can be identified and interpreted at the
landscape, site, and field scales
• At the landscape scale (> 1:10,000 scale), it is
possible to interpret polygons to the level of
Community Class & Community Series
easily...and to Ecosite with some experience +
data
• At the site scale (< 1:10,000 scale), it is possible to
interpret polygons to the level of Ecosite &
Vegetation Type (Ecoelement), with data and
experience
• On the ground – today’s technology allows GPS of
polygon boundaries and delineation in the field
Polygon Identification
• Polygons should be interpreted remotely using
aerial photography and confirmed on the ground
using topographic base mapping.
• Landform, slope position, drainage, vegetation
cover and other attributes are used to identify
polygons.
• Use all available information sources to assist
you in refining polygon boundaries (e.g. soils and
physiography maps, historical survey records and
vintage air photos).
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Polygon Rules
• Minimum polygon size is 0.5 hectares
– 0.5 ha = 5000 m2; 50m x 100m; 1.2 ac
– 0.5 ha is the MMU at 1:10,000 scale
• Polygons are often traversed by roads, rail, watercourses,
easements, etc.
• If a discontinuity is detectable on 1:10,000 scale air photos,
then separation should be considered, even if the polygons
are similar.
Polygon Variability
FOD2-4
SWD1-3
Ft. Erie Slough Forest System (SWD1-3/FOD2-4)
How to Deal with Variability
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Variability is normal and natural.
It should not be feared.
It should not be ignored.
Do Not Panic when confronted with it.
Focus on the signal not the noise.
ELC can handle it.
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Polygon Variability
Does the variation within a polygon suggest two
or more distinct classes, series, ecosites or
ecoelements?
Yes
No
Is the variation isolated
to a single patch ?
Yes
No
Treat as one polygon. Treat as an
Sample the variation. Inclusion
Treat as a
Complex
Inclusions & Complexes
• Used to describe situations where there are two
or more ecosystem conditions within the same
polygon
• Pertain to features that are too difficult to map
due to their small size or other factors
• Inclusions are isolated ecoelements within the
polygon matrix that do not meet the MMU
• Complexes are characterized as two or more
consistently recurring patterns within the polygon
matrix, and smaller than MMU
Polygon Inclusions &
Complexes
SWD3-3
FOD
SWD
MAM2-2
MAS2-1
Figure 17. (FG pg 143)
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Polygon Inclusions &
Complexes
ELC data cards must be completed for each
inclusion and complex vegetation type and included
with the polygon data.
FOD6-5 = 10.5 ha / SWT2-4 = 0.5 ha
Forest
Deciduous Forest
Fresh-Moist Sugar Maple Deciduous Forest
Fresh-Moist Sugar Maple-Hardwood Deciduous Forest
Buttonbush Mineral Thicket Swamp
FO
FOD
FOD6
FOD6-5
SWT2-4
Decisions
Polygon Sampling
1. captures just the prevailing conditions
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ignore the inclusions and complexing
sampling is confined to prevailing conditions
within the polygon
2. captures complexing and inclusions
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Ecosite sampling...associated ecoelements
sampling inclusions and complexes
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