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Chapter 5: Vegetation

Manitoba displays a large range of vegetation types that are arranged with a climatically determined north/south zonation. Grass-covered areas in the south give way to parkland and forested areas further north and eventually to shrub tundra in the extreme northeast.

5.1: Broadleaf Deciduous Forest in Turtle Mountain

Areas of broadleaf deciduous forest are limited in Manitoba, the best examples being in Turtle Mountain—shown here—and the Brandon Hills. “These are quite unlike the broadleaf deciduous forests in eastern Canada, being dominated by aspen (Populus tremuloides) and bur oak (Quercus macrocarpa)”.[i]

Figure 5.1 is a high-level, small-scale photo of the western part of Turtle Mountain that straddles the Canada/U.S.A. border. A thick layer of hummocky moraine that supports a deciduous tree cover blankets the surface. At the time the photo was taken, the trees bore green leaves that result in a dark-grey tone 1 with mottled texture. Numerous lakes occupy depressions in the moraine; some are large enough to be named on the 1:250,000 map of the area: Lake Metigoshe 2, Dromore Lake 3, Partridge Lake 4, Sharpe Lake 5, Nellie Lake 6, Gordon Lake 7, Cauldwell Lake 8, and Rebecca Lake 9. The lakes vary in tone from dark-grey—Lake Metigoshe, to almost white—Cauldwell Lake, resulting from the specular reflection effect.

On the Canadian side of the border little forest has been cleared for agriculture within Turtle Mountain and a large segment has been designated as Turtle Mountain Provincial Park, the northern boundary of which can be picked out on the basis of land use 10—forested in the park to the south and cleared for agriculture to the north. The international border 11 can also be picked out on the basis of the same land use variation—mainly forested in Canada with more agricultural clearing in the U.S.A.

In Canada sections of the DLS system are clearly seen 12 with gravel roads along some section lines 13. PR 450 follows section lines in the north but diverges westward 14 to avoid Sharpe Lake in the south.

5.2: Broadleaf Deciduous Forest in the Brandon Hills and Riverine Gallery Forest in the Assiniboine Valley

In this high-level, small-scale photo deciduous forest in the leaf-on stage appears as very dark grey tones. The Brandon Hills 1, part of the Darlingford end moraine, are almost completely forested apart from a steep-sided, light-toned, grass-covered ridge at the east end 2. Riverine gallery forest—in this area mainly aspen (Populus tremuloides) and bur oak (Quercus macrocarpa)—shows as dark tones along the east bank of the Assiniboine River 3 as well as along the course of the Little Souris River 4. The light grey tone east of the Assiniboine 5 indicates that the land is mainly grass covered. Spring sapping has caused an eastward retreat of the east bank of the Assiniboine 6. West of the river several indefinite northwest/southeast trending lines 7 probably represent high-level Lake Agassiz strandlines. Poorly drained marshy land can be seen between them 8.

Most of the rest of the area is devoted to agriculture with the characteristic checkerboard pattern of the DLS. Occasional patches of deciduous trees interrupt the cropped landscape 9. Gravel roads follow most section lines. Their upkeep is a major drain on the financial resources of rural municipalities, and with the rural depopulation so representative of the area, many are likely to be abandoned.[i] PR 340 10, locally called “the Sunshine Highway” because it heads south from Brandon, runs east of the Brandon Hills, and with five right-angled bends on its route, clearly demonstrates the influence of the land division system on road directions in this area. Other transport lines include the north/south CN railway line 11 which used to terminate at the Prince Edward Hotel in central Brandon[ii] and the east/west CP line near the southern edge of the photo 12. The angular dark-toned areas in the northeast corner 13 are sewage lagoons for the town of Shilo, just off the photo to the northeast. The light-toned line leading from the lagoons to the Assiniboine 14 is a buried sewage pipeline.

The area is sparsely populated. The Brandon Hills settlement 15, occupied before Brandon was established, and Rounthwaite 16 are now completely abandoned. The greatest concentration of population is at the Hutterite Colony at Glen Souris 17.

5.3: Vegetation of the Assiniboine Valley and Assiniboine Delta in the Area of Spruce Woods Provincial Park

On panchromatic (black and white) air photographs the green leaves of deciduous trees produce a dark-grey tone. In this area the Assiniboine River 1 has incised itself into the sands of the Assiniboine Delta. River cliffs 2 and point bars 3 exist at several locations. Several abandoned channels 4 are also visible, one of which, known locally as Big Island 5, is of recent origin.

Riverine gallery forest—very dark-grey toned—is located along both sides of the Assiniboine Valley (6 and 7) as well as along the valley floor 8 when it has not been removed for agriculture. In this area the forest includes cottonwood (Populus deltoides), Manitoba maple (Acer negundo), green ash (Fraxinus pennsylvanica), basswood (Tilia americana), and willow (Salix spp). Elms (Ulmus americana) are also found but “many are dying from Dutch elm disease which reached Winnipeg from North Dakota in 1975”[i] The sand dune areas north and south of the river have a mixed vegetation cover. The dark-toned areas 9 are areas of deciduous woodland, principally aspen (Populus tremuloides) with occasional patches of white spruce (Picea glauca). One area in the centre 10 is being cleared of trees. Light-toned areas 11 are grass covered.

Most of this area lies within Spruce Woods Provincial Park and has been left in its natural state. However, some land on the valley floor 12 as well as an area in the southwest 13—outside the park—has been cleared for agriculture. The area is devoid of settlements, and only a few minor roads 14 and paths 15 can be identified.

5.4: Mixed Deciduous/Coniferous Woodland on the Assiniboine Delta North of Glenboro

In figures 5.1, 5.2, and 5.3, all of which are photographs obtained during the summer, deciduous woodland was identified on the basis of its dark tone. Figure 5.4, a fall photograph of an area southeast of the Assiniboine River 1, north of Glenboro, illustrates the usefulness of fall photos in vegetation studies. At this time of year deciduous trees are changing colour; for example aspen (Populus tremuloides) leaves turn a delicate yellow and are imaged as a very light tone 2. Other deciduous trees are imaged as a darker grey 3 and coniferous trees—probably white spruce (Picea glauca)—are very dark-grey 4 and can also be identified from the triangular shadows they throw 5. Light-toned grasses 6 with occasional coniferous trees identified by their dark tone and triangular shadow 7 cover much of the land northwest of the Assiniboine River. Circular dark-toned areas with no relief in one field in the southwest 8 are probably patches of creeping juniper (Juniperus horizontalis).

Land along the Assiniboine has been cleared for agriculture, revealing prominent meander scrolls 9 with river cliffs 10—slumped in one case 11—on the outside of meander bends. Section lines of the DLS system are visible 12 with PTH 5 between Glenboro and Carberry 13 following the system before bending in the north 14 to miss a meander of the Assiniboine.

[[fig. 5.4]]

5.5: Riverine Gallery Forest in the Souris Valley Near the Elbow of Capture

This high-level, small-scale photo shows the Souris River 1 where it runs through a 90° turn to change from flowing southeast to northeast and then cuts through the Tiger Hills 2, eventually joining the Assiniboine near the small settlement of Treesbank (off the photo to the north). West of the elbow of capture 3 the Souris flows in a glacial spillway that continues eastwards with only a very minor stream channel 4 occupying its floor.

Riverine gallery forest on both sides of the Souris, above 5, 6 and below 7, 8 the elbow of capture, along both sides of the glacial spillway 9, 10, as well as along small tributary valleys 11 is identified solely on the basis of its dark tone. North of the line of the Souris River and the spillway, patches of dark-toned deciduous woodland cover part of the Tiger Hills end moraine 12, but south of the valleys almost all the land has been cleared for agriculture.

In the agricultural area to the south the sections of the DLS system are obvious 13; gravel roads follow most section lines and PTH 23 14 is a more definite light tone than the gravel roads. In the Souris Valley and the spillway, the topography clearly influences the direction followed by some roads 15 with a hairpin bend in one case 16, a rarity on the roads of southern Manitoba. The CN railway line runs east/west across the photo 17 passing through Dunrea 18 and Margaret 19, the latter now almost abandoned.

[[fig. 5.5]]

5.6: Riverine Gallery Forest in the Pembina Valley East of Snowflake

The misfit Pembina River 1 occupies the floor of a glacial spillway that carried water from glacial Lake Hind, to the west, into glacial Lake Agassiz. Here the spillway has an asymmetrical cross-profile because the channel slid off to the southwest cutting a steep bank 2 and leaving behind a gentle slope on the northeast 3. Several small lakes 4 exist on the south wall of the spillway in low-lying land between slumped blocks.

Almost all the southwest side is covered by riverine gallery forest 5, including in this area cottonwood (Populus deltoides), Manitoba maple (Acer negundo), green ash (Fraxinus pennsylvanica), willow (Salix spp), and basswood (Tilia americana). Elms (Ulmus americana) that used to exist here are dying because of Dutch elm disease. Similar forest exists on the northeast wall 6, but here on southwest-facing slopes the microclimate is drier leading to patches of grassland 7. Forest also exists along the course of the Pembina River 8.

As in previous figures the main criterion for identifying forest is its dark tone, but in this case the scale is large enough that, using a magnifying lens with the original photo, the rounded crowns of the deciduous trees can be identified; they produce a mottled texture 9.

The Pembina River with numerous cutoffs 10 meanders southeastward through the area. Some land has been cleared for agriculture along the valley floor 11 and on flatland south of the valley 12. Clusters of farm buildings 13 can be seen in both locations. Only one road 14 crosses the Pembina, but numerous forest trails 15 exist on both sides of this valley.

[[fig. 5.6]]

5.7: Riverine Gallery Forest in the Valley of the Little Saskatchewan River South of Rivers

The Little Saskatchewan River 1 flows southward across the area, and at the time the photo was taken, the channel was full of water, but several boulder barriers across the stream can be identified 2.

The large scale of the photograph makes it possible to identify individual deciduous trees 3 and the rounded shadows they throw 4. Deciduous forest—here mainly aspen (Populus tremuloides) and bur oak (Quercus macrocarpa)—occupies wetter land on either side of the river channel 5 as well as small “draws” leading down to the river 6. Low-lying bushes—dark-toned but without obvious tree crowns— cover an area in the southwest 7, and patches of light-toned grass also occur 8. The latter should not be confused with land that has been cropped and which shows the linear patterns associated with cropping 9. A track leading down to the river 10 probably originates at a farm building off the photo to the east. Small dark spots in the northeast may be cattle 11.

[[fig. 5.7]]

5.8: Riverine Gallery Forest on the East Side of Pelican Lake

This infrared photograph shows part of the east shore of Pelican Lake 1, a shallow lake on the floor of the Souris-Pembina spillway. Infrared photographs employ a false colour technique in which objects reflecting large amounts of infrared radiation—which the human eye cannot see—are imaged as red. Photo-synthesizing vegetation typically reflects large quantities of infrared so that live healthy vegetation is imaged as bright red.

Here, along the east wall of the spillway, riverine gallery forest, mainly aspen (Populus tremuloides) and bur oak (Quercus macrocarpa), shows up in bright-red tones with mottled texture 2. The scale of the photograph is large enough that rounded shadows thrown by individual trees can be identified 3. A clearing within the forest contains low-lying bushes that are imaged as pink 4. Rounded patches 5 suggest that these are creeping juniper (Juniperus horizontalis).

In the north, crops are growing in five fields 6. In the western-most of these it can be seen that the crop is growing well in some areas 7 but not so well in others 8. Three fields that have been left fallow 9 are imaged as dark green, but in the southernmost field weed growth results in a pink tinge 10.

The v-shaped projection into Pelican Lake 11 is one of several similar features located near the mouths of small streams. This point, known locally as Y point, has been used as a summer camp for over 100 years[i] and cottages have been built along the shore 12. A major problem for Pelican Lake as a recreational resource is that it is very shallow and has little through-flow of water. Contamination of the water leads to algae growth in the summer; the pink colouring on both sides of the point (13 and 14) are a result of this.

5.9: Natural Vegetation Surrounding the Red River Plain

This Landsat image shows radiation from the earth’s surface in three wavelength bands: 0.5 to 0.6 micrometres (green), 0.6 to 0.7 micrometres (red), and 0.8 to 1.1 micrometres (infrared). Printing was done so that objects reflecting large amounts of infrared radiation were imaged as red. At the time the image was obtained (September 17, 1973) this applied to trees, shrubs, and grasses growing in the area. Water bodies range from very dark blue to light milky blue, the latter being the case where there is a large suspended sediment load. In the northeast, the Winnipeg River 1 flows through a series of expansions, the largest being Lac du Bonnet 2, before entering Lake Winnipeg 3. The southern end of Lake Manitoba 4 is seen in the west, and in the Interlake region the Shoal Lakes (west 5, east 6, and north 7) as well as many smaller lakes can be seen.

Three main areas of natural vegetation can be identified. In the southeast, mainly on the Canadian Shield 8, is an area of provincial parks and forests. In the extreme east the vegetation is broadleaf forest with an area of mixed-woods bordering it. This area also has numerous areas of “poorly drained lowland bogs with their black spruce-sphagnum communities, and of granite rock outcrops with their thin, often only 15 cm thick, organic soils (folisols) dominated by jack pine to the north and white, red and jack pine to the southeast. Some of the acid sphagnum peat in the Agassiz Forest bogs near Beausejour and Hadashville [9 and 10 on the image] is harvested for horticultural purposes.”[i] The continuity of this forest/bog area is broken by clearing for agriculture only along the Whitemouth River 11, the Brokenhead River 12, and the upper reaches of the Seine River 13.

The second area is the Interlake region 14 between lakes Winnipeg and Manitoba. Here the natural vegetation is categorized as aspen parkland[ii] with aspen (Populous tremuloides) being the dominant tree. The thin poorly drained soils of the area are at best marginal for agriculture, so there has been little clearing except for a spur projecting along the west coast of Lake Winnipeg 15.

In the third area in the southwest on the Pembina Hills 16, the redness is less uniform because of agricultural clearing. In this area small patches of broadleaf forest occur on the higher ground with the rest being aspen parkland.[iii]

Delta marsh 17 at the south end of Lake Manitoba and Netley Marsh 18 at the south end of Lake Winnipeg show up as lattice works of vegetation surrounded by water. These marshes are subject to frequent water level changes and therefore have not been reclaimed for agriculture, in contrast to the marshes that used to exist on the Red River plain further south. At the end of the nineteenth century the plain, which extends from Portage la Prairie in the west 19 to the Canadian Shield in the east 20 and from Lake Winnipeg in the north to well south into the U.S.A. 21, was covered by marshes. They have almost all been drained for agricultural use, and as the active growth period for crops was past when this image was obtained, little of the plain is shown in red.

There are, however, a few exceptions. In the north, Oak Hammock Marsh 22 “has been maintained as an important wetland and staging area for migratory waterfowl by regulating water levels and practicing periodic draw down.”[iv] It is imaged as red, but there is little indication of standing water. Another red area northeast of Winnipeg 23 results from woodland in Birds Hill Provincial Park, and the red area south of the Assiniboine River in western Winnipeg 24 indicates the presence of treed parks. Also, several river courses can be located on the basis of linear red zones: in the west the Assiniboine 25, La Salle 26, and Boyne 27; in the south the Red 28 and the Rat 29; and in the east the Seine 13 and Brokenhead 12.

The emphasis here is on interpretation of natural vegetation, but three cultural features should be mentioned: Winnipeg is located at the junction of the Red and the Assiniboine rivers 30; the white areas 31 northeast of Winnipeg are gravel pits into the Birds Hill esker; and the Red River Floodway which bypasses the city to the east 32 is red because of grasses growing on its banks.

5.10: Distribution of Natural Vegetation in Central Manitoba

This Landsat colour composite was obtained on August 15, 1973 at which time the natural vegetation was reflecting large amounts of infrared radiation and therefore appears as red/orange in the image. Water bodies are imaged in various shades of blue: dark where there is little suspended sediment and pastel where there is a large suspended load.

In the northeast is Lake Winnipegosis 1 that drains from Long Island Bay 2 by the West Waterhen River 3 into Waterhen Lake 4 that in turn drains south via the Waterhen River 5 into the north end of Lake Manitoba 6. Dauphin Lake 7, a basin of inland drainage, is located further south. In the north are the south ends of Pelican Lake 8 and Swan Lake 9. Surrounding the large lakes in the northeast are numerous small lakes occupying structural depressions in the Interlake Region 10. In the south is the long, narrow Lake of the Prairies 11 created by a dam across the Assiniboine River at Shellmouth (off the south edge of the image).

Three highland areas—Riding Mountain 12, Duck Mountain 13, and the Porcupine Hills 14—are covered by thick moraine with numerous lake-occupied depressions. In Riding Mountain, Edwards Lake 15, Moon Lake 16, Shoal Lake 17, and Gunn Lake 18 can be identified. In Duck Mountain, Childs Lake 19, Laurie Lake 20, and Singush Lake 21 can be seen in the centre; Madge Lake 22 and Bearhead Lake 23, just west of the Manitoba/Saskatchewan border, can be seen in the west; and Wellman Lake 24 is in the north. In the Porcupine Hills, Whitefish Lake 25, South Steeprock Lake 26, North Steeprock Lake 27, Bell Lake 28, and the eastern part of Armit Lake 29 can be seen.

The red/orange tone of Riding Mountain is broken in the north by a slightly lighter toned area 30, the result of a forest fire. The same arrangement can be seen in central Duck Mountain 31—also the result of a fire. In these lighter toned areas, although the vegetation has regenerated since the fires, it is not as strong as in the surrounding regions. In the case of the Porcupine Hills there is a uniformly red/orange fringing zone 32 surrounding a less uniformly toned interior 33; the latter is a morainic lake-covered area whereas the steep fringing zone has few lakes.

Outside the three hilly areas most of the land west of Lake Winnipegosis is wooded, as is the Westlake region 34. The valleys between the hills (35 and 36) and the land southwest of Duck Mountain 37 have been cleared for agriculture, although occasional wooded areas occur, for example, along the upper Assiniboine Valley 38, in the valley of Big Boggy Creek 39, and on some Lake Agassiz strandlines 40.

A few clouds are seen on the image mainly in the southwest 41 and west 42. Over Duck Mountain small cumulus clouds cast shadows to the northwest 43, indicating that the image was obtained in the morning.

[[fig. 5.10]]

5.11: Vegetation in the Central Part of Duck Mountain

The photograph shows the lake-strewn central part of Duck Mountain. On the image lakes show in various grey tones, depending on their depth, suspended sediment load, and the sun/camera/water surface relationship (the specular reflection effect). East Blue Lake 1, West Blue Lake 2, Swallow Lake 3, Beautiful Lake 4, Whitemud Lake 5, Elk Lake 6, Island Lake 7, and Singush Lake 8 all appear as dark grey, whereas Cache Lake 9 is light grey, and a small, unnamed lake in the east 10 is almost white.

Almost the whole area is covered by natural vegetation, in this area mixed woods consisting of coniferous trees on higher land and birch (Betula papyrifera) and aspen (Populus tremuloides) in better-drained lowlands. The dominant trees are probably white spruce (Picea glauca) and black spruce (Picea mariana). Wooded areas are dark-toned 11 with light-toned areas of aquatic vegetation surrounding some of the lakes 12. It is noticeable, however, that the northwest is lighter toned 13, the result of a forest fire. This is the same scar that can be seen on the LANDSAT image in figure 5.10.

The area is almost devoid of human occupation, but some recreational development is seen at the north end of East Blue Lake 14 and south of Marge Lake 15. Two major transport routes intersect on the photo: the east/west PR 367 16 and north/south PR 366 17.

[[fig. 5.11]]

5.12: The Northern Edge of Riding Mountain National Park

The photo shows the sharp demarcation line between the essentially natural vegetation in Riding Mountain National Park 1 and the Gilbert Plains to the north 2, almost completely devoted to agriculture.

South of the park boundary 3 the natural vegetation consists of mixed woods: coniferous trees, including white spruce (Picea glauca) on higher land and black spruce (Picea mariana) with birch (Betula papyrifera) and aspen (Populus tremuloides) on well-drained lowlands. The woodland is represented in very dark-grey tones 4 with lighter-toned areas of aquatic vegetation around small lakes 5. Two large areas of light tone in the southwest 6 and southeast 7 are the result of a forest fire. This area can also be identified on satellite images (figure 5.10).

Drainage from this part of Riding Mountain is to the north via a series of steep-sided valleys, from west to east: East Wilson River 8, Renicker Creek 9, and Ranch Creek 10. These continue northeast across the gently sloping Gilbert Plains. The checkerboard pattern of the DLS is visible in this intensively cropped area. A few small patches of woodland remain 11 as well as fingers of riverine forest along the river courses 12.

[[fig. 5.12]]

5.13: Vegetation on the Riding Mountain Escarpment

On this photo of the Riding Mountain Escarpment, drainage is to the east in a series of steep-sided valleys of which Dead Ox Creek 1 in the centre is the largest. The creeks have eroded down through a thick veneer of moraine to reveal the underlying Cretaceous shales—white-toned—in many locations 2. This is particularly noticeable on the outside of creek bends 3, and at one location, Bald Hill in the north 4, a sharp-crested ridge of shale is exposed.

The natural vegetation in this area is mixed woodland with deciduous trees: aspen (Populus tremuloides), balsam poplar (Populus balsamifera), and birch (Betula papyrifera) dominating. These produce a light-grey tone 5, and in some places the rounded crowns of trees can be seen 6 producing a mottled texture. Darker toned coniferous trees, white spruce (Picea glauca) and black spruce (Picea mariana), dominate in a few places 7, and isolated conifers can be identified on the basis of their dark tone and triangular shadow shapes 8.

The only indications of human impact on the area are PTH 19 9 that crosses Riding Mountain from west to east and one of the park’s walking trails 10.

[[fig. 5.13]]

5.14: Natural Vegetation in North Central Riding Mountain National Park

The Vermilion River 1 drains north and is joined by a right bank tributary 2 which is in turn joined by tributaries from the east (3 and 4). The landscape is covered by mixed-woods with light-toned deciduous trees: aspen (Populus tremuloides), balsam (Populus balsamifera), and birch (Betula papyrifera) in the west 5. Rounded crowns produce a mottled texture 6. In the south 7 dark-toned coniferous trees—black spruce (Picea mariana) and white spruce (Picea glauca)—are more common, and in the northeast many isolated coniferous trees are identified from their dark tone and triangular shadows 8. Along the Vermilion River are light-toned areas of grassland and aquatic vegetation 9 and a series of dark-toned ponds 10 along the eastern tributary. These are the result of beaver dams—light-toned strings 11 across the river. Beavers (Castor canadensis) like all forms of wildlife are protected within the park, but controversy has erupted when beaver dams have broken, resulting in flooding of agricultural land beyond the park boundary.

The only evidence of human influence is a trail (The Strathclair Trail) 12 trending north/south across the region. This is a warden patrol trail. A small star-shaped area 13 west of the Vermilion defies easy explanation.

[[fig. 5.14]]

5.15: Natural Vegetation Near Moon Lake in the North Central Part of Riding Mountain National Park

Moon Lake 1 is located on the right. At the time the photo was taken, there must have been a strong wind disturbing the lake surface resulting in a variety of tones and textures. Surrounding the lake are areas of mixed deciduous/coniferous woodland. In the southwest light-toned deciduous trees dominate 2 with isolated coniferous trees probably white spruce (Picea glauca) identified by their dark tone and triangular shadow 3. Several patches of more closely spaced coniferous trees are located in the northwest 4. One linear patch 5 in a wetter zone north of an unnamed lake 6 could contain tamarack (Larix laricina) trees. In the extreme west a small dark-toned lake 7 has drowned some forest, killing trees in the process. East of Moon Lake coniferous trees dominate 8, almost forming a closed canopy.

PTH 10 9 between Minnedosa and Dauphin runs through the area with a forest access road leading to the west 10. A microwave tower with a long thin westward-falling shadow 11 is situated in a clearing along the road. A campground at the south end of Moon Lake 12 is one of many in the national park. It has access roads from east, west and south 13. A favourite walking/cross-country ski trail which circles the lake starts and ends at this point although it is too narrow to show on the photo.

[[fig. 5.15]]

5.16: Colour Infrared Photo of Natural Vegetation in the Central Part of Riding Mountain National Park

This low-level, large-scale colour infrared photo shows natural vegetation in the central part of Riding Mountain National Park, north of Clear Lake. In this summer image both deciduous trees and coniferous trees are reflecting large amounts of infrared radiation and are therefore imaged as red. In some areas deciduous trees with rounded crowns producing a mottled texture 1 predominate, whereas in others coniferous trees with both a triangular shape and shadow 2 are in the ascendancy. West of PTH 10 3 radial displacement is large enough that trees are seen partly sideways on so that light-toned trunks 4, probably of birch trees (Betula papyrifera), are visible.

Three small lakes 5 that are almost black because they reflect little infrared exist in this area. The northernmost is ringed by low-lying aquatic vegetation 6 with some algae growth 7 offshore. Trees that are imaged as greenish-yellow have been killed by water in several locations 8.

The only indications of human influence are PTH 10 with a car traveling along it 9 and a small side road leading to a jetty 10.

[[fig. 5.16]]

5.17: Mixed Vegetation Near Lake Audy, Riding Mountain National Park

The photograph shows the northern part of Lake Audy 1 with the Little Saskatchewan River 2 draining into it from the north and Jackfish Creek draining to it from the east 3. Another small, unnamed lake 4 can be seen in the south. It was once considerably larger and is now ringed by emergent aquatic vegetation 5.

Vegetation includes deciduous woodland, coniferous woodland, and grassland. Deciduous woodland, light-toned with a mottled texture, is widespread 6, whereas dark-toned coniferous woodland 7 is more localized. Very light-toned grassland covers a large area east of the lake 8 and a smaller area to the north 9. Much of the vegetation is natural, but some coniferous trees have clearly been planted 10. The main grassed area is used as a compound for a buffalo herd, one of the few left on the prairies. Tourists are allowed to drive along a peripheral trail 11 in order to view the animals. Large though they are, they are not big enough to show up on this small-scale photo. A faint cut line through the deciduous woodland is probably the location of part of the fence around the compound 12.

Several trails lead into and out of the area 13, one leading to the campground 14 on the lakeshore.

[[fig. 5.17]]

5.18: Mixed Vegetation in the Area of Gunn Lake, Riding Mountain National Park

In the top left-hand side of the photo is Gunn Lake 1. A valley to the south 2 connects the lake with Whitewater Lake, off the photo to the southeast, although there is a stream 3 along only a part of it. At one place this stream is dammed 4 producing a small lake 5 that has killed off trees, some of which can be seen floating in the lake. Light-toned deciduous woodland 6 covers much of the centre with some patches of dark-toned coniferous woodland in the east 7. Coniferous woodland also dominates some poorly drained low-lying areas 8 in the valley and around small lakes. The trees are probably tamarack (Larix laricina) which flourish in wet conditions. In addition to woodland, there is one area of very light-toned even-textured grassland 9.

The only indications of human influence are two hiking/biking/cross country trails, the easternmost of which 10 crosses mainly woodland and appears to be flooded in the north 11. The other trail 12 is well known locally because it crosses the grassland, a colourful walk/ride in the spring as the flowers bloom.

[[fig. 5.18]]

5.19: Colour Infrared Photo of Vegetation on the Assiniboine Delta Southeast of Shilo

Shown here is part of the Assiniboine Delta where the sands of the delta have been blown into dunes 1 and then stabilized by vegetation. The area, of little agricultural value, has been used as a military training ground for over 50 years. This large-scale colour infrared photo illustrates the usefulness of colour infrared images for identifying vegetation. At the time the photo was taken—late fall—all the deciduous trees had lost their leaves and were therefore not reflecting infrared radiation, but coniferous trees still had needles that reflect infrared and are imaged as red or orange.

Five vegetation types can be identified using the standard criteria for photo identification—tone—including in this case colour, texture, pattern, shape, size, and location. The most obvious vegetation zone is a thick red band trending northwest/southeast across the centre 2. Trees occur in rows indicating that they were planted, and their red colour and triangular shape and shadow indicate that they are coniferous. A field check revealed that they are Scots Pine (Pinus sylvestris L.) which are not native to this area. Near the southern edge of the photo are two small patches (3 and 4) of coniferous trees—red, with triangular shape and shadow. Given their location on the sand dunes, they are probably white spruce (Picea glauca). Isolated individual white spruce 5 can be seen scattered over the area south of the plantation. Also widespread over the whole area, but especially north of the plantation, are orange patches 6 often assuming a circular form 7. This vegetation throws no shadow, so it is not high off the ground. It is creeping juniper (Juniperis horizontalis) that, as its name suggests, spreads horizontally, especially over flat land. Much of the area is covered by vegetation imaged as pale green/almost white 8. Shadows indicate that we are dealing with trees, in this case aspen (Populus tremuloides) that have lost their leaves. Finally, there are extensive areas of pale green, smooth-textured grasslands 9.

The area is crossed by many tracks with a main one along the southern edge of the plantation 10 that leads from Shilo to the central part of the military reserve. Others are trails used by military vehicles. An indicator of how frequently they are used is given by whether they are covered by creeping juniper (as at 11). The only other indicator of human activity is a cluster of buildings north of the plantation 12 that is possibly a rifle range.

[[fig. 5.19]]

5.20: Vegetation Near Plum Lakes

The large shallow water area of Oak Lake and Plum Lakes is a relic of glacial Lake Hind; as the glacial lake dried out these remnants were left. Part of the Plum Lakes exists in the northwest 1 and northeast 2. Almost all the northern two-thirds of the photo was recently covered by water, and in addition to the Plum Lakes, several other small relic lakes remain 3 some bounded by low dikes 4. Emergent aquatic vegetation is visible in several of the shallow lakes 5. The slightly higher land has been reclaimed for agriculture—in this case hay growing. At the time the photo was taken the hay harvest was complete, and hay piles can be seen scattered throughout the area 6. Numerous trails cross this area 7.

The southern third is quite different, being covered by sand dunes which result from lake deposited sands being blown into dunes. Some well-defined ridges 8 can be identified. There are a few bare sand patches 9 but almost all the dunes are stabilized by vegetation—mainly deciduous trees and grass. The deciduous trees had lost their leaves by the time the photo was taken; consequently their shadow shape 10, their medium-grey tone, and mottled texture can identify the trees. Grass, on the other hand, is light grey with a smooth texture 11. On the dune ridges, microclimate variations result in different vegetation covers: on wetter northeast-facing slopes, trees dominate, whereas drier southwest-facing slopes are grass-covered 12. Two dugouts 13, probably supply grazing cattle in the sand hills. Apart from some trails there is little evidence of human activity, other than farming.

[[fig.5.20]]

5.21: Beaver Dams in the Central Part of Riding Mountain National Park

The photo shows an area of mixed vegetation in the central part of Riding Mountain National Park. Deciduous trees with light tone and mottled texture 1 cover most of the area; also present are occasional patches of dark-toned coniferous trees 2 as well as scattered individual coniferous trees 3. At least one patch of coniferous trees occupies a depression 4 and is probably tamarack (Larix laricina). Some very light-toned grassland areas 5 are distributed throughout the area.

Several small streams 6 flow across the area. In some places they have been blocked by beaver dams 7 to produce lakes—very dark-toned—upstream 8. Usually the lakes are narrow occupying creek valleys 9, but in one instance water has spread over a wide area 10 killing trees. A lake that has since drained occupied another dark-toned area 11.

In this central part of the national park there is little evidence of human activity except a poorly defined trail 12 that has been flooded in two locations 13.

[[fig. 5.21]]

5.22: Part of Delta Marsh West of Delta Beach on the South Shore of Lake Manitoba

Delta Marsh extends for over 25 miles (40 km) along the south shore of Lake Manitoba 1. The marsh, which experiences large water level fluctuations, has never been reclaimed for agriculture, in contrast to land further south. This photo of the western end of the marsh shows a series of small streams 2 draining to the lake and several lakes 3. The distribution of open water and aquatic plant vegetation make this internationally famous delta marshland an ideal habitat for duck breeding. Ditch reed, bulrushes, and cattails are common aquatic plants. The beach is gentle with sand bars 4—often with a boulder barrier 5 at the back—driven into place by ice during the winter.

The University of Manitoba operates a research station on the delta, but the only indicator of human activity is a path along a levee 6 with offshoots to west 7 and east 8, the latter running along the south edge of the only woodland in the area 9.

[[fig. 5.22]]

5.23: Fen and Black Spruce Islands South of East Braintree

Teardrop-shaped islands 1 are surrounded by almost horizontal fen 2 covered by low-lying vegetation. The islands are covered by black spruce (Picea mariana), dark-toned, 3 and tamarack (Larix laricina), light-toned 4. The surface form of the islands is determined by surface and groundwater flow.[i] The terrain is very difficult to cross; hence the absence of any obvious human impact.

5.24: Spring Fens West of Dancing Point, West Shore of Lake Winnipeg

The location is close to the junction of Ordovician and Silurian bedrock. Rocks of both periods include dolomite with argillaceous bands, and springs develop at the contacts. In the photo light-toned drainage way can be seen running from springs in the north 1 and centre 2. These are “spring fens”. They usually occur directly over springs in places where springs are widespread. The peat in spring fens varies in depth from shallow to deep but is thinner than peat in plateaus.[i] Wooded islands, probably covered by black spruce (Picea mariana), can be seen in the south 3, and the outline of a recent burn is in the lower left 4.

5.25: Ribbed Fen East of Warren Landing, North End of Lake Winnipeg

Ribbed fen with slightly elevated ridges of vegetation 1 at right angles to the direction of water movement occupies much of the centre of the photo. Ground water flowing to the west coalesces into drainage channels 2 that become Oscar Creek 3 that in turn drains into the upper reaches of the Nelson River (off the photo).

[[fig. 5.25]]

5.26: Floating Fen in Shirley Lake West of North Moose Lake

The photograph shows the north end of Shirley Lake 1. In the southeast are near-circular checkored mats of floating fen peat 2. Further south are small rounded floating peat mats 3. The floating rings on the extreme south 4 may be lily pads. A dike runs across the north 5, but its purpose is not obvious.[i]

5.27: String Fens and Peat Plateaus West of Setting Lake

This area lies within the Lake Agassiz Basin where bedrock is covered by till and glaciolacustrine deposits on which peat has developed ranging from 1 metre to 5 metres in thickness. String fens, with strings transverse to the direction of surface and ground water movement, can be seen at several locations 1. These surround peat plateaus 2, some of which are high enough and dry enough for dark-toned black spruce (Picea mariana) to grow 3. Some plateaus are lighter-toned because forest fires have removed trees 4. The very light-toned areas on the peat plateaus 5 are collapse scars resulting from melting of ground ice. Permafrost exists in the plateaus but not in the strings on the low-lying areas between them. Two of the peat plateaus 6 are good examples of the common teardrop shape with streamlined tails indicating the direction (to the south) of sheet run-off and ground water flow.[i]

5.28: String Fens and Peat Plateaus East of Kettle Rapids

This is a good example “of string, net, and anastomosing fens as well as pancake-shaped, wooded peat plateaus with collapse scars. The area is situated in the northern part of the discontinuous (permafrost) zone where the mean annual temperature is -5°C and widespread permafrost is 25 metres thick. Permafrost is absent beneath both the flarks and strings at this location. The two dominant tones are related to the native vegetation: the dark tones are dominantly black spruce [Picea marina] and acid-tolerant shrubs, and the light tones are mainly tamarack [Larix laricina] and sedge with some sphagnum. Most of the peat plateaus have central depressions due to thawing of the permafrost and consequent settling of the ground. The sedge meadows in these collapse scars produce light tones. Peat thickness is predominantly 2 to 6 m. Stratified clayey silt and silty sand of glaciomarine origin underlie peat and overlie varved glaciolacustrine clay, which in turn rests on silty ablation till. Ground water running through these highly calcareous mineral sediments feeds nutrients to the fens.[i]

Fen ridges that are oriented parallel to the topographic contours are best observed along a line (1 to 2 to 3). Here the individual strings are mostly serpentine and sub-parallel, but at a few places they appear either closely interwoven or merged. They are spread apart at 4, and at 5 they are bunched together. This alternation of open and closed patterns suggests slight differences in gradient. On flatter areas the strings tend to form netlike patterns, whereas on gentle to moderate slopes they produce string patterns of variable spacing. Similar pattern variations are noticeable further west 6. Light-toned collapsed peat plateaus can be seen at several locations 7.

5.29: Peat Plateaus and Sloping Fens Near the Mouth of the Hayes River

In this area the coastal plain is being rapidly uplifted. Peat covers a discontinuous veneer of recent over- bank alluvial deposits over marine silt and clay or wave-modified till. The Hayes River 1, transporting a large sediment load, is braided with in-channel islands: Rainbow Island 2, Seal Island 3, and Fishing Island 4. The Nelson River can be seen in the upper left corner 5. Wanatawakaw Portage runs from near Rainbow Island to the Nelson River.

Oval peat plateaus are well-developed 6. The regular outlines of these plateaus suggest that they are actively expanding over the surrounding fens, many of them eventually coalescing (as at 7). Collapse scars can be detected on the centre of some of the plateaus 8. The streaked pattern 9 of the gently sloping fen is created by sheet runoff in the spring and by ground water flow. The light tones also reflect vegetation responses to water quality. Dark tones indicate fairly nutrient-rich fens, with tamarack (Larix laricina) and shrubs in the sedge. Light areas are located down- slope from peat plateaus 10 where these interrupt the regional flow and the water is coming off the peat plateau. Here the water is poor in nutrients and more acid. The poorer nutrient and oxygen status, as well as the low PH values, produces a poorer fen with fewer trees and shrubs.[i]

The north bank of the Hayes is retreating rapidly under the combination of thermal and fluvial erosion, and a pile of debris 11 can be seen at the base of a bank failure.

5.30: Palsas in Wet Fenland South of Churchill

In this area a surficial layer of marine silt overlies silty till.[i] It lies within the area of discontinuous permafrost; i.e., there are areas where water below ground is continually frozen. A series of creeks including Alston Creek 1 and Wakworth Creek 2 drain northward ultimately into the Churchill River just off the photo to the west. Palsas—ice-filled peat mounds—are light-toned and circular to oval 3. The surrounding fen is lower, wetter, and darker 4. The fen is also darker along drainage ways 5 where the permafrost is thawed and the active layer—the layer in which ice melts during the summer—is thicker. In the area, marked 6 ridges and ponds display a reticulate pattern, giving rise to the term "net fen." There are vestiges of raised strandlines 7, now about 100 feet (30.5 m) above sea level. Above the general level of the strandlines are numerous lakes, some of which are darker-toned 8, whereas others are very light 9 due to specular reflection.

The thin white line in the west 10 is the Hudson Bay Railway leading north to Churchill. The whistle point Bylot 11 is located at the bend in the line. Construction began at The Pas in 1910 and was completed on March 29, 1929. The total distance from The Pas to Churchill is 510 miles (816 km), much of it over spongy muskeg and discontinuous permafrost. The building of the line was a remarkable engineering feat, but maintenance costs over discontinuous permafrost have been high and in recent years the existence of the line has been constantly threatened. It is now owned and run by an American company.

5.31: Non-Oriented and Oriented Lakes South of Churchill

This area is within the northern part of the discontinuous permafrost zone near Cromarty on the Hudson Bay Railway line just off the photo to the west.

In this area peat that is typically about 2 metres thick overlies glaciomarine silt or silty till. The peat began to develop about 6500 years ago as the post-glacial Tyrrell Sea withdrew from the Hudson Bay Lowland. With the onset of a colder climate, permafrost invaded the peat. “The development of tundra ponds begins with the thawing of ice wedges, followed by seepage of water into the central part of the peat polygons, causing thawing and then subsidence. Continual wetting and refreezing of the peat increases its thermal conductivity and rate of thawing until shallow, flat-bottomed ponds are created. These ponds enlarge, coalesce and deepen by the melting of ground ice and subsidence until the glaciomarine silt or silty till is reached, which forms the flat floors. With continuation of this process the coalescing ponds expand in time to form small lakes. These lakes may enlarge even more from lake ice push, wave action and undercutting of the peat in summer, and from thermal erosion by warmed water around the peaty lake shores.”[i] Numerous roughly circular ponds 1 can be seen. These lakes are flat-bottomed and generally less than 3 metres deep. Also seen are many larger lakes, the largest of which are Lovell Lake 2 and Morantz Lake 3. These lakes are flat-bottomed, probably less than 3 metres deep. Several drained lakes—light-toned—can be seen 4. The prevailing northwest winds push water, waves, currents, and sediments to the southeast forming prograding shelves in several locations 5. Also resulting from these processes are straight southeast shorelines on several lakes 6. Dark tones along Kelsey Creek 7 indicate melting of permafrost along the riverbanks.

In the northeast is an elevated area—about 200 feet (61 m) a.s.l.—with spit-like ridges 8 which probably represents an old Tyrrell Sea shoreline. A spur from the Hudson Bay Railway line 9 runs to this area in a series of straight stretches avoiding lakes. Very light-tone areas 10 at the eastern end of the spur are probably sand and gravel pits exploiting the raw materials in the spit.

5.32: Delete 5.32

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