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The Ottawa Valley: Lanark County as a microcosm

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Library in Plant Ecology


Lanark County is a microcosm of the OttawaValley .

Consider geology. Lanark County has Precambrian rock in the west, as you find in the upper Ottawa Valley (including Algonquin Provincial Park) as well as limestone in the east, as you find in the lower Ottawa Valley (including the city of Ottawa).  There are also extensive areas of marble. About ten thousand years ago, the western side of Lanark county was flooded by an enormous glacial lake, while the eastern side was flooded by the> Champlain Sea. Hence there are extensive clay plains, of both fresh water and marine origins, which extend from Lanark County all the way to Montreal . 

 When the first Europeans arrived, the area was mainly deciduous forest, but there were also fire barrens and pine ridges, as well as lakes and beaver ponds and extensive swamps.  The history is also typical: indigenous peoples were replaced by Europeans, predominantly Scottish and Irish settlers, who logged the forests and cleared for farms.  On deeper soils there are now prosperous communities, while on shallow and rocky soils, farming collapsed and the forests are recovering.

In spite of two centuries of human settlement, there are still important natural areas left.  These include alvars, rock barrens, and wetlands.  There are also distinctive southern species including five-lined skinks, black rat snakes and southern flying squirrels. Shagbark hickories have crept as far north as some rocky south-facing hillsides, while a stand of hackberry trees clings to the limestone cliffs along the rapids in Carleton Place.

So whether you live in LanarkCounty, or elsewhere in the Ottawa Valley, the book Earth, Water, Fire: An Ecological Profile of Lanark Coounty is a solid introduction to the natural heritage and human history of the area. You can purchase the book from stores including Mill Street Books in the historic town of Almonte, The Book Gallery on 19 Lake Avenue West in Carleton Place, or from The Bookworm in downtown Perth.

To download a brochure click here.

To view a 45 minute presentation on this topic, click here


The Christie Lake fire barrens are introduced on page 49 in Earth, Water, Fire.  To read an on line supplement, click here.


The Carleton Place hackberry forest is introduced on page 59 in Earth, Water, Fire.  To read an on line supplement, click here.


For a reading list of scientific papers on the natural environment of the Ottawa valley, click here.


To read a report on pre-settlement forests, click here.


For a short guide to restoring Lanark County forests, click here.