What about ANTIGUE FORESTS? This article is from BEN (Botanical Electronic News) # 144. Adolf Ceska <aceska@victoria.tc.ca> WHAT ARE THE ANTIQUE FORESTS ? (RE: BOTANY BC FIELD TRIP) From: Trevor Goward, Nature Canada - Summer 1994. As a rule, lichen colonization in a maturing forest occurs in two pulses. The first consists of various species of widespread distribution, and is essentially complete by the time the forest reached the century mark. The second, more diffuse pulse doesn't really begin to register until 50 to 100 years later. It is comprised of species living at or near the ecological limits of their range; many will remain rare even once they do become established. These phenomena are by no means peculiar to the conifer forests of western North America. Similar patterns have already been amply documented in Britain by lichenologist Francis Rose (1976). In mid-'70s, Rose conducted inventories of the lichens of 102 oak and beech woodlands in different parts of the British Isles. When later he compared his species lists against existing land use records, he found a definite positive correlation between lichen diversity and forest age. This led him to conclude that some lichens may be regarded as "historical indicators of lack of environmental change, within certain critical limits, over long periods of time." British forests undisturbed for many hundreds of years typically support between 120 and 150 lichen species per square kilometre. The richest forest for lichens by far is the New Forest which ironically, is anything but new, having apparently escaped woodcutter's axe since at least the Middle Ages. It was found to contain an astonishing 259 species of lichens. By contrast, British woodlans dating from less than 200 years ago tend to support fewer than 50 lichens per square kilometre. In the British Isles, as in British Columbia, a 150-year-old forest will not acquire its full complement of epiphytic lichens for at least another century or two. The fact obliges us to think again about what we mean when we speak of "old growth." Should an old-growth woodland 1000 years old be lumped, for the purposes of conservation, with one that is "only" 200 years old? Both forests may appear identical to the untrained eye. But they clearly are not identical - whether as living archives of British Columbia's past, or as repositories of biological tradi- tion. "Antique forests," as I define them, are simply the oldest of the old: forests that have been around long enough to accumu- late, among other things, a rich assemblage of old-growth epiphytes. Such forests seem invariably to be more than 300 to 350 years old, and many, in many cases, have been in existence much longer than the most ancient trees within them. The last point is important. A 150-year-old tree in a 500-year-old forest may well support more old-growth indicators than a 250-year-old tree in a forest dating from a fire of equivalent vintage. Goward, T. 1994. Living antiquities. Nature Canada, Summer 1994: 14-21. Goward, T. 1994. Notes on oldgrowth-dependent epiphytic macro- lichens in inland British Columbia, Canada. Acta Botanica Fennica 150: 31-38. Rose, F. 1976. Lichenological indicators of age and environmen- tal continuity in woodlands. Pp. 279-307 in: Brown, D.H. et al. [eds.] Lichenology: progress and problems. Academic Press, London.
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