|
This
is an initial ecosystem-based plan; some desirable analysis topics
are yet to be completed (such as a history of logging disturbance
on the island) and some analyses may need to be modified or improved
over time as additional community input is received. This project
was carried out using funds contributed by both the Cortes Island
Forest Committee and the Silva Forest Foundation. Further analysis
will require additional funding or will have to be done by the
skilled volunteers in the CIFC.
This
plan is intended to fit within the framework of the approved Cortes
Official Community Plan, adopted by the Regional District
of Comox Strathcona in 1995. In this analysis, at the direction
of the CIFC, we limited our analysis to the identification of:
-
ecologically sensitive terrain which is not suitable for resource
extraction and development activities
-
areas which should be protected from human use to maintain
ecosystem functioning at the landscape scale
Planning
human uses on the remaining landbase of stable and moderately
stable terrain is left to the community and their existing Cortes
Official Community Plan.
Ecological Sensitivity to Disturbance (ESD)
Map
Silva ESD
ratings are based on combinations of soil depth, slope, soil moisture,
and terrain complexity. This data layer is derived through a combination
of air photo interpretation and GIS modeling. The Ecological Sensitivity
to Disturbance zone types are delineated on 1:17,000 black and
white air photos, and then imported into the GIS.
Definitions
of the terrain classes identified on Cortes island:
- ES1 and/or
ES 7 areas are predominantly located in valley bottom areas,
or near lakes. Only larger riparian ecosystems or wetland complexes
were identified on air photos, and computer generated buffers
around wetlands and streams were added in later steps.
- ES 2 terrain
includes all areas with slopes greater than 60% gradient. Such
slopes are unstable and prone to landslides and other forms
of erosion, especially after logging and road construction.
- ES 4 sites
are areas which are dissected by gullies or which contain convoluted,
hilly terrain. The combinations or small steep slopes, dry sites,
and areas of shallow soil make these sites unsuitable for timber
management.
- ES 5 sites
have soil less than 50 cm deep over bedrock.
- MS or Moderately
Stable sites are "in between" ES terrain and Stable
terrain, with slopes in the 30 to 60% range. We excluded 75%
of this from the timber management landbase to allow for the
inoperable areas which are expected to be found when the area
is field surveyed.
- S or Stable
sites are areas with moderate slopes, deep well drained soils
and even terrain. We included 100% of the forested area of S
terrain in the potential timber management landbase.
Area of SFF Terrain Classes
Information
gained during the field assessments was used to revise and improve
the initial ESD interpretations. The highlights of the information
gained from the field work are:
- Rocky knolls
and ridges are common in elevated parts of the island.
- Streams
and creeks are difficult or impossible to see on the air photos
because of sense vergetation.
- The 1:17,000
air photos understate ground slope, leading to a tendency to
underestimate slope steepness and ecological sensitivity.
Different
widths of riparian buffers were generated in the GIS system for
the landcover classes:
Intermittent Creeks: 20 m
Year Round Creeks: 50 m
Fishbearing Creeks: 100 m
Wetlands: 50 m
Lakes and Ocean Shoreline: 100 m
Old Growth
Forests
Map
The southern
Cortes Island landscape has been overwhelmingly impacted by logging.
The scattered old growth Douglas-fir trees that now stand like
sentinels in small groups were once average sized trees in blanket
of old growth forest. While the lush second and third growth forests
we now see on Cortes are beautiful, they are ecologically very
different from the old growth fir, cedar and hemlock forests that
they have replaced. Unless management plans are implemented to
restore old growth structures to all forest types, the magnitude
of the ecological changes will increase over time.
The first
step in restoring old growth forests within the Cortes landscape
is to identify the old growth forests which currently remain on
the island. The first draft of mapping was carried out by the
SFF using 1:17,000 black and white air photos. Mapping "old
growth" form air photos is problematic; there is no way to
measure the age of a tree on air photos. We used crown form, crown
width, and tree height to identify what we believed were old forest
areas. Old trees generally have wide, ragged crowns and are significantly
taller than second growth forests. We identified two classes of
old forests on the island:
- High Density
Old Growth: Areas with more than 10 stems per hectare of old
growth trees. Generally, these are intact stands which have
not been logged. High density old growth is rare in the more
settled portions on the island, but becomes more common moving
onto the central spine and up onto Von Donop peninsula. These
areas are proposed for protection.
- Low Density
Old Growth: Areas with less than 10 stems per hectare of old
growth trees. Generally, these are logged areas or rocky, sensitive
sites with a few scattered old growth trees. Low density old
growth forests on stable and moderately stable terrain remain
in the potential timber landbase, with the caveat that any logging
activity in the area must not impact the stems or roots of the
large old trees. This will likely require buffer zones around
all individual trees.
David Shipway
of the CIFC then performed further photo interpretation and extensive
field inspection of the photo interpreted old growth stands, and
his changes were incorporated into the database.
We believe
that old growth forests once dominated the landscape of Cortes
Island. However, extensive logging and resulting fires around
80 to 100 years ago have greatly reduced the area of remaining
old growth. Currently, only 6% of Cortes Island is occupied by
high density old growth forests, and a further 23% falls within
the low density class. The low density old growth class is not
"old growth forest", but is generally a natural open
area or logged area which contains some large old growth structures.
While ecologically valuable, low density old growth areas are
not an ecological substitute for full canopied old growth forests
on good growing sites.
Because there
is so little old growth left on Cortes Island, all remaining high
density old growth forests on Cortes Island should be protected
from timber cutting and other activities that significantly alter
their composition, structure, and function. The current old growth
forests will be supplemented over time by old growth stands which
develop within the protected landscape network. This process will
take at least another century, but there is no way to speed up
the creation of old growth forests.
Land Ownership
Map
Land ownership
status is a critical parameter in this analysis, as ownership
determines the responsibility for land and forest management decisions.
Land ownership on Cortes Island rests with a variety of institutions
and groups, including:
- The Provincial
Government, as administered by the Ministry of Forests
- MacMillan
Bloedel Limited
- Many smaller
private landowners
- Other levels
of government or other Ministries (in charge of various protected
areas)
We used the
land ownership information contained in the forest cover map data
files as the base for land ownership mapping. We amended the forest
cover data file as follows to improve the ownership mapping to
required standards:
- MacMillan
Bloedel holdings were mapped from a 1974 map provided by the
CIFC entitled Managed Forest Land - MacMillan Bloedel,
which was drawn by the Regional District of Comox Strathcona
Planning Department.
- The forest
cover data mapping of other private land was updated in several
locations per CIFC instructions.
- The boundaries
of existing Class "A" Provincial Parks (Von Donop
Marine Park and Manson’s Landing Park) were digitized from
map and written information provided by Rik Simmons of the Ministry
of Environment Lands and Parks, Strathcona District.
- The boundaries
of the proposed Carrington Bay Park were digitized from a map
provided
by Alison Mewett of the Regional District of Comox Strathcona
Planning Department.
- The boundaries
of the Hague Lake / Gunflint Lake proposed park were digitized
per the CIFC.
Protected
Landscape Network
Map
Forest landscapes
contain a full array of ecosystem types and have a successional
pattern through time that is tied to unpredictable natural disturbance
regimes. Such natural landscapes are fully occupied by plants,
animals, water, nutrients, and energy. Extensive modification
of these landscapes results in degradation, loss of ecological
integrity, and, if human perturbations are persistent, in ecological
collapse. Scientists and planners now recognize the need to maintain,
protect, and/or, where necessary, restore a framework of ecosystems
throughout the landscape to ensure connectivity and ecosystem
functioning at all scales, from the small patch or stand to the
large landscape.
Some human
uses may also be expected to occur in selected portions of the
protected landscape network. For example, hiking trails, built
and used to ecologically responsible standards, may be designated
in various portions of the protected landscape network.
Elements of
a protected landscape network should not be confused with large
protected areas, parks, or wilderness reserves. Large protected
areas are required throughout the landscape to provide reservoirs
of fully functioning ecosystems and the biological blueprints
required to reestablish functioning in landscapes degraded by
human activities.
The economics
of the proposed protected landscape network do not need to be
negative for the local economy. On Cortes, tourism employment
and economic opportunities are possible within protected areas,
within portions of the protected landscape network, and throughout
areas of stable terrain. A high quality environment is known to
benefit a broad selection of small and home-based businesses.
Maintaining a healthy ecosystem requires landscape level planning
and balanced human uses based on ecologically responsible standards.
In coastal
landscapes, the commercial and sports fisheries are also critical
components of an ecosystem based economy. These fisheries depend
upon the protection and maintenance of fully functioning forests
that provide the creek habitat and water quality required by fish.
Landbase
Unsuitable for Development
Map
Elements from
the previous maps were combined to create a map of areas unsuitable
for development on Cortes Island. Because the design of the map
is to remove areas from the landbase that are not suitable, anything
that remains, displayed in white, may be suitable for ecologically
sustainable forest management. Before any cutting would take place,
each of these areas would need to be assessed at a stand level
to determine if any ecological functions that they serve may have
been overlooked in the landscape analysis.
|
