The Ancient Cliff Face Forest

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The northern half of the Saugeen Peninsula supports the oldest living trees in Canada east of the Rocky mountains, some as old as 1300 years.

At the 2010 Sources of Knowledge Forum, Peter Kelly, a researcher with the Cliff Ecology Research Group at the University of Guelph presented a summary of what the group had learned about this ancient forest of eastern white cedar which clings to the sheer rock face on the eastern side of the Saugeen Peninsula.

It is quite extraordinary that the existence of this primeval forest was not officially known until 1988 when the University of Guelph conducted a number of research studies along the whole length of the Niagara Escarpment. In order to learn more about the forest, in particular, whether it shared some of the characteristics of other ancient forests around the world, another study was conducted at eleven sites including Bears Rump and Halfway Log Dump. The result was that every site found old growth forest and it showed the same characteristics as old growth forest in other, very different habitats in other parts of the world. These were a freedom from widespread human disturbance, a large number of old trees in the forest and a wide distribution of age among the trees. Thus, at Bears Rump and Halfway Log Dump more than 25 per cent of the trees were more than 250 years old.

The study found evidence that the eastern white cedar can live for over a thousand years. One dead specimen was 1,032 years old when it died. In the area of the Grotto, several trees were up to 560 years old but, unlike the ancient trees on the west coast of North America, which grow to a great size, the trees in this old forest are small. That is because, as the study confirmed, the trees grow very slowly. One specimen was found to have added an average of 0.25 grams of new wood each year, making it the slowest growing tree in Canada.  

According to Kelly, the cedars possess “sectored radial architecture whereby specific parts of the stem are connected to specific root clusters within the rock.” When part of the root dies, perhaps due to drought conditions in that part of the rock, it does not affect the whole tree but only the part of the stem to which the root is joined. Water is not distributed evenly throughout rock and its distribution is uneven. Accordingly, some of the tree’s roots may be in drought while others are able to access water. The root dies first and this leads to the death of the stem to which it is connected. A tree was found on Bears Rump Island that had lost part of its original cambial surface (that part of the tree between the bark and the stem which produces new growth) 600 years before the rest of the tree died.

An effort to preserve these ancient trees, called the Niagara Escarpment Ancient Tree Atlas Project, was started in 1998. The intention was to identify where they are so that they could be protected. This project led to the discovery of 124 living cedars along the Escarpment that were more than 500 years old. Ten were over 1000 years old and two of these were over 1300 years old. All were inside the Lions Head Provincial Nature Reserve.

Peter Kelly and Douglas Larson of the University of Guelph have published an illustrated book about the ancient forest on the peninsula called The Last Stand. One of the observations they make is the interesting distribution of eastern white cedar versus that of other native species on the west side of the peninsula. They found that cedar is the most dominant tree on the cliff face but ten metres back from the cliff edge they cease to be dominant and give way to the typical Great Lakes forest such as maple. Those cedars at the transition point show suppressed growth compared with those on the cliff edge.

The study of tree rings is called Dendochronology. The variation in the pattern of tree rings tells a lot about climatic conditions at the time the ring was forming. The results of studying the ancient trees along the escarpment shows that tree growth rates were higher in the 20th century than for any other period in history of this forest. According to Kelly the inevitable conclusion is that we are experiencing an unprecedented period of climate change and that the increased growth rates may spell the end, in the long run, of this ancient forest given that its survival is linked to the ability of the trees to grow slowly.

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