Boreal mixedwoods are made up of stands with varying proportions of hardwoods and
conifers. Considerable variation in species composition occurs, depending on site
conditions and past disturbances.
The boreal mixedwood cover type is aesthetically appealing and houses a rich and
diverse flora and fauna. While valued for timber production, other values such as
wildlife and recreation are equally important in the integrated management of this natural
resource. These values meet social needs and protect ecosystem diversity. Integrated
resource management that encompasses all values is critical for the sustainable
development of boreal mixedwoods.
The Black Sturgeon Forest is an important supplier of timber and pulpwood to the
forest industry of Thunder Bay. Forest conditions and the management problems they
pose are typical of mixedwood stands throughout many other parts of northern Ontario
second-growth stands with a high component of poplar and balsam fir, the latter species
making them susceptible to severe spruce budworm infestations. This forest has a long
history of research that goes back to the 1940s, much of it concerned with the spruce
budworm and related issues.
The Black Sturgeon Boreal Mixedwood Research Project was established in 1993 to
respond to the need for a strong ecological foundation for integrated resource
management in boreal mixedwood forests. Through long-term studies that focus upon
stand-level ecosystem processes we gain a much better understanding of these highly
variable ecosystems, including their structure and dynamics, their response to disturbance
and manipulation, and the nature of the inter-relationships among different ecosystem
elements. These elements encompass all those things that together influence the unique
development of the forest you see before you trees, lesser vegetation, wildlife, climate,
soils, insects, disease, fire, and man, among others.
The project comprises three main components that evaluate ecosystem impacts and
responses to: (i) different harvesting methods, (ii) prescribed burning, and (iii)
mechanical site preparation. Each block of the harvesting and prescribed burning
treatments shown on the map is 10 ha. Started in 1996, the blocks receive various
treatments (seeding, planting, etc.) aimed at regenerating the forest.
Within the project areas, researchers are studying a broad range of factors. These factors
include: vegetation changes; forest succession and development; climate; soil nutrients;
soil fauna; wildlife, including birds, mammals, and amphibians; insects, in particular the
spruce budworm; and diseases, especially in relation to logging damage. The aim is to
determine how forestry operations affect the intricate balance within boreal mixedwood
ecosystems. The fire ecology component will allow direct comparison of the impacts of
fire and harvesting upon these ecosystems. Mechanical site preparation can have many
of the same effects as logging. Regeneration success resulting from the use of
mechanical site preparation will be weighed against other impacts.
Three harvesting patterns are being investigated within this project: the clear up, the
partial cut and the patch cut. Through our harvest prescription we can vary the amount of
processing on site, and the amount of logging material removed from the site, by
specifying the equipment and how it is to be used. Mechanical feller-bunchers are
designed to sever a tree from the stump and hold that severed tree while reaching and
cutting another tree. It can repeat this procedure until several trees are cut and its jaws
are full. No delimbing or further tree processing takes place. This is referred to as a full-
tree logging system. These trees can be sorted and piled for efficient removal by grapple
skidder. This harvesting system is very well suited to clear-cut operations.
Other tree harvesters can cut, delimb, and top trees at the stump. Skidders then remove
only the tree-length from the site, leaving the tops and branches on site. The most
sophisticated harvesters can cut, delimb, and process the tree into logs and pulpwood at
the stump for forwarding to the roadside. This is called a cut-to-length system. By
making them relatively small and maneuverable, some of these harvesters can operate
successfully under partial cut conditions. The type of harvester used, the number of skid
trails, and the amount and placement of slash left, of removed, from the site will have an
effect on subsequent stand performance.
Cut and skid harvesting was employed in some of the partial cuts and in creating the
patch cuts. Manual tree felling with chain saws and subsequent processing of the tree at
the stump, prior to skidding to the roadside, is probably the most adaptable and least
capital intensive harvesting system in the boreal forest.
When it was surveyed in 1994, the second-growth forest of the Black Sturgeon in the
project study area was composed of 20-50 percent poplar, 30-60 percent balsam fir, 10
percent white spruce, 10-20 percent black spruce, and 10 percent white birch, with small
pockets of jackpine. Due to the ravages of the spruce budworm (the latest outbreak
began in the early 1980s), the composition of this forest is currently undergoing major
change through the elimination of the mature balsam fir component.
Before the arrival of the European settlers, two natural forces the spruce budworm
and wildfire were an integral part of the ecology of boreal mixedwoods and played a
major role in their periodic renewal and successional development. The spruce budworm
and fire are still important considerations in the management of these forests.
The spruce budworm, a small caterpillar 2-3 cm long that feeds on the buds and shoots
of balsam fir and spruce, periodically devastates large tracts of boreal mixedwood forest.
Spruce budworm outbreaks occur in approximately 40 year cycles between peaks.
Infestations may last for 10 years or more. At the end of an outbreak, about 80% of the
balsam fir and 50% of the white spruce will be dead. In the Black Sturgeon Forest most
of the host trees had died by the time of the 1994 survey, as a result of the current
infestation. The insect population is expected to collapse by the late 1990s.
While forest companies can attempt to keep ahead of the budworm by harvesting
mixedwood stands containing balsam fir and white spruce before the budworm does, the
number of dead trees that result from major outbreaks far exceeds the amount of wood
the mills can use. For many years, chemical insecticides were used to protect the forests,
but these are now being phased out in favour of natural biological control agents.
Fire is a natural phenomenon in the boreal forest, and plays a fundamental role in
regulating species diversity and forest health. Through fire protection we may be losing
the natural character, vigor, and faunal and floral diversity of boreal mixedwoods. Most
noticeably, the balsam fir content has increased as a result of fire protection, thereby
increasing the budworm-susceptibility of these forests.
The recent devastation of the balsam fir component of these boreal mixedwood stands by
the spruce budworm has created ideal conditions for wildfire. Uncontrolled wildfires are
clearly unacceptable. Prescribed fire, on the other hand, has the potential to play a
significant role in the management of these ecosystems to reduce the balsam fir
regeneration, control crop tree competition, improve wildlife habitat, and promote
The History of Forestry in the Black Sturgeon Forest
Logging was first introduced into the Black Sturgeon Forest around 1936. Between 1936
and 1945, Great Lakes Paper (est. 1926) logged the forest for white spruce sawlogs and
for pulpwood. All logging was done using axes and cross-cut saws. No chainsaws, tree
harvesters or wheeled skidders then! Horses were used to skid the wood out to skidways,
where it was piled. Later, the logs would be loaded onto bobsleighs for the haul to frozen
waterways. In later years, specially modified trucks would pull the trains of loaded
sleighs to the lake of riverside. And, with spring ice breakup, everyone participated in
the exciting and often dangerous river drive on the Black Sturgeon River system to Black
Bay. Once in the bay, the logs were boomed into large rafts that were then towed by
tugboat to Thunder Bay.
All loggers lived in camps near the area being logged. Camp 1 was established at the
base of Eskwanonwatin Lake, near the dam built at the same time, around 1936 or 1937.
Pastures were cleared for horses. Barns and a blacksmith shop were built. Bunkhouses,
a cookhouse, a camp clerk's office, and various outbuildings were constructed to house
and operate a small self-contained community.
In those days, logging was a seasonal occupation. The men would begin logging in late
August. About mid-December, tree felling would cease and hauling would begin if the
ground was frozen and there was sufficient snow for the sleighs. This would continue
until the season's wood was piled on or beside the frozen waterways ready for spring
breakup. If spring was late, balsam fir would sometimes be cut at this time and peeled by
hand. The season would end with the spring river drive. It was a rugged life for the men
who logged for a living.
Around 1940, Camp 7 was set up just north of this sign to house the loggers who worked
in this area. In the early 1960s the area was again logged to remove the merchantable
white pine. Loggers stayed at Camp 9, just north of the bridge at Nonwatin Lake.
Health concerns for the forest and the potential for losing valuable timber to insect attack
and fire developed on the heels of logging activity. An epidemic of spruce budworm in
the 1940s drew the attention of forest entomologists from the newly formed Forest Insect
Pathology Laboratory in Sault Ste. Marie. A summer field station was established on
Black Sturgeon Lake where Outward Bound now resides. From 1945 until the mid-
1970s federal researchers monitored insect activity and tested control measures for this
insect pest. A year after the federal field station opened, the Ontario Department of
Lands and Forests established a Chief Ranger Headquarters further north on Black
Sturgeon Lake to provide fire protection and forest management support to the area.
The collapse of the spruce budworm populations eventually led to a decline in the federal
research presence in the area, although certain long-term studies continued to be
monitored. Likewise, changing priorities in the late 1960s resulted in closing the Chief
Ranger base on Black Sturgeon Lake and turning over the facilities to Lakehead
This is a "second-growth forest" because it originated from the first harvest of virgin
timber in the 1940s. The present stand in composed of trees that were saplings and
suppressed seedlings living in the understory at the time of the first timber harvest, as
well as new seedlings that developed in stand openings after harvest. Some early
colonizers, such as poplar, were able to increase their presence through suckering from
the disturbed roots and stumps of harvested parent trees. The pines, spruces, and birches,
if not already present as seedlings and advance growth, established themselves from
seed. Establishment by seed requires a happy combination of available seed source,
desirable seedbed, and conditions suitable for germination, survival, and continued
growth. Tree species such as balsam fir are very shade tolerant, and can establish
themselves and survive for long periods under the main canopy in very low light
The composition of this stand is changing. Logging, insects, disease, and fire will
remove higher proportions of some species than others. In the scramble to recolonize
after disturbance, some species are favoured to reestablish on the site. Relative growth
rate and longevity determine which species dominate and at which times during the life
cycle of this dynamic forest.
Boreal mixedwood forests are the most diverse and productive sites in the boreal forest
zone. The abundance and variety of food and shelter provided by the boreal mixedwood
forest sustain a varied and plentiful spectrum of wildlife.
Approximately 150 bird species breed in boreal mixedwood forests. Of the over 60
species of songbird identified during a one month period from mid-June to mid-July,
ovenbirds, red-eyed vireos, Swainson's thrushes, bay-breasted warblers, and yellow-
bellied flycatchers are most common here. Each species fits a niche in this environment.
Some are seed eaters, some feast on the spruce budworm, others catch flies and
mosquitos, and still others prefer beetles, grubs, or worms. Woodpeckers, sapsuckers,
owls, grouse, crows, and even the stately bald eagle can be seen within these woods.
Bears find abundant food and shelter within these boundaries. Porcupines, chipmunks,
mink, voles, deer mice, rabbits, foxes, wolves, moose, and many other animals inhabit
this bountiful forest.
Amphibians such as the northern leopard frog and wood frog, American toad, and
redback salamander are and essential link in the forest ecosystem. They feed on insects
that feed on smaller organisms that break down dead material and speed its incorporation
into soil and nutrients to aid new growth.
The birds, animals, the small creatures and soil fauna all have a role to play in this boreal
mixedwood forest ecosystem. They depend on each other much as a chain is only as
strong as its weakest link. A weakening or removal of any of these links could have far-
reaching effects on the subsequent development and character of the future forest.
The Black Sturgeon Boreal Mixedwood Forest Brochure
(Funded by The Northern Ontario Development Agreement, Northern Forestry Program - Natural
Resources Canada; Ontario Ministry of Natural Resources)
For more information on the Black Sturgeon project, contact:
Ministry of Natural Resources
Northwest Science and Technology
RR#1 - 25th Side Road
Thunder Bay, ON
Tel. (807) 939-2501
Natural Resources Canada
Canadian Forestry Service
Great Lakes Forestry Centre
P.O. Box 490
Sault Ste. Marie, ON
Tel. (705) 949-9461
Fax. (705) 759-5700
You can find more Internet information on Black Sturgeon at: www.glfc.forestry.ca/english/network/bmixedwood.html
The Black Sturgeon site is part of a larger research effort known as FERNS (Forest Ecosystem Research Network of sites). You can get information on this research at: www.pfc.cfs.nrcan.gc.ca/practices/ferns.htm
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