baumzaehlen - Primeval Forests & Their Trees

©2017copyright christoph hase

Prince Albert National Park, Saskatchewan, Canada

 

Parts of the park area (3874 km2) have been logged before the creation of the park, but there are unlogged wilderness areas in the northern part. The park is located between altitudes 488–732 m. Lying south of the Canadian Shield, it is covered by thick glacial till sediments1; bare rock can scarcely be seen anywhere. Annual precipitation is approx. 450 mm with a summer maximum and average annual temperature approx. 0°C 1.

 

Before 1890, the fire cycle in the northern part was as short as 15 years. Then it became longer and since 1945 there have been practically no fires; the change may derive from fire suppression or from climate change. Fires were usually stand-replacing. The largest known fire burned approx. 2000 km2 within the park in 1890. Since 1765, the entire park has burned at least once. 7 % of the northern part of the park has been fire free since 1845, and 45 % since 1895.2

 

Tree species diversity is low and the species are easy to identify. In gently sloping North American boreal forest landscapes, long fire-free periods allow so much organic matter to accumulate that succession is often towards low boggy Opens internal link in current windowPicea mariana (black spruce) forest or even true bogs and fens3. Opens internal link in current windowPicea glauca (white spruce) and Opens internal link in current windowAbies balsamea (balsam fir) are more shade-tolerant than P. mariana3, but the latter tolerates better the difficult conditions of boggy forest4. In addition to P. mariana, old forests contain P. glauca, Opens internal link in current windowPopulus tremuloides (quaking aspen), Opens internal link in current windowPopulus balsamifera (balsam poplar) and Opens internal link in current windowPinus banksiana (jack pine). There is dense A. balsamea regeneration in places but mature A. balsamea is a very rare sight. In the absence of fires, the proportion of A. balsamea will probably increase; it is the most shade-tolerant and regenerates most successfully on undisturbed humus but it is fire-sensitive5. Opens internal link in current windowLarix laricina (tamarack larch) grows on bogs in addition to P. mariana. The tallest tree species is P. glauca, which can attain 35 metres. Of the broadleaf trees, P. tremuloides is the tallest with maximum height of about 30 metres.

 

There are no marked hiking trails in the northern wilderness of the park. Off-trail hiking is not easy: in more lush forests there is often dense A. balsamea regeneration, in old P. mariana forests there are half-fallen trees tumbled everywhere, and much of the area is boggy. Camping outside the designated places is allowed further than two kilometres from any public highway or designated campground with the exception of some popular big lakes.

 

References:

 

1       Acton, D. F., Padbury, G. A. & Stushnoff, C. T. (1998): The Ecoregions of Saskatchewan. Canadian Plains Research Center.

2       Weir, J. M. H., Johnson, E. A. & Miyanishi, K. (2000): Opens external link in new windowFire frequency and the spatial age mosaic of the mixed-wood boreal forest in western Canada. Ecological Applications 10(4), 1162-1177.

3       Heinselman, M. L. (1981): Fire and Succession in the Conifer Forests of Northern North America. In West, D. C., Shugart, H. H. & Botkin, D. B. (eds.): Forest Succession. Concepts and Application. Springer.

4       Henry, J. D. (2002): Canada’s Boreal Forest. Smithsonian.

5       Thorpe, J. P. (1992): Patterns of diversity in the boreal forest. In Kelty, M. J. (ed.): The Ecology and Silviculture of Mixed-Species Forests. Kluwer.

 

Official site:

 

http://www.pc.gc.ca/pn-np/sk/princealbert/index.aspx

 

Video clip:

 

http://www.youtube.com/watch?v=FbMMnTicPsY

 

Picea mariana (black spruce) dominated forest. Also Populus tremuloides (quaking aspen, with furrowed bark) and dense Abies balsamea (balsam fir) regeneration, background.
Picea mariana (black spruce) forest with one Populus tremuloides (quaking aspen) snag, left centre.
Unnamed small lake. Picea mariana (black spruce, narrow crowns). Picea glauca (white spruce, broader crowns, left). Larix laricina (tamarack larch, light green crowns, centre). Populus tremuloides (quaking aspen, broadleaf trees, left).
Unnamed small lake. Mostly Picea mariana (black spruce) and Picea glauca (white spruce).
Unnamed creek. Picea mariana (black spruce, dark green crowns) and Larix laricina (tamarack larch, light green crowns).
Background: Picea glauca (white spruce) forest with two Betula papyrifera (paper birch) trees.
Floodplain of small creek with beaver dams. Picea mariana (black spruce) dominated forest. Also Larix laricina (tamarack larch), foreground right and at forest edge.
Alnus incana ssp. rugosa (speckled alder) along small creek. Background: mainly Picea glauca (white spruce), also narrow crowns of Picea mariana (black spruce).
Fen with Larix laricina (tamarack larch) along small creek. Also Picea mariana (black spruce) sapling, centre, and Picea glauca (white spruce), left background.
Boggy Picea mariana (black spruce) forest.
Picea mariana (black spruce) dominated forest. Also two Populus balsamifera (balsam poplar, furrowed bark) trees, centre, and sprouts, foreground; two Populus tremuloides (quaking aspen, white trunks) trees, background right; P. mariana regeneration, right.
Picea (spruce) canopy. Background left: P. mariana (black spruce); foreground, from centre to right: P. glauca (white spruce), P. mariana and P. glauca. Also Populus balsamifera (balsam poplar), background centre.
Pinus banksiana (jack pine) stand with some Picea mariana (black spruce, with dense foliage) and P. mariana regeneration.
Salix bebbiana (beaked willow).