Text for an article that appeared in (Newsletter for Five Bridges Wilderness Heritage Trust November 2009 )

Old Growth Oak and Red Spruce in the Five Bridge Lakes Wilderness Area

By Nick Hill & David Patriquin (Sept. 30, 2009)

Beth McGee and others of Five Bridge Lakes Wilderness Heritage Trust have long been convinced that the FBLWA holds untold treasures. Amongst them, they suspected, are old growth forest stands known to Ralph Wheadon when he was working in the area. (Ralph, now retired, knows the Chebucto Peninsula intimately from a lifetime of work as fire warden, as well as holding other responsibilities for DNR, in the area.) During July and August, we checked out two areas cited by Ralph as worthwhile to examine, one an oak stand on a hill [drumlin] east of Oak Hill Lake and, the other, red spruce on higher elevation land [drumlin] southeast of Lower Trout Lake. We were not disappointed by what we found!

The oak stand is quite unlike any other we have seen in Nova Scotia. It is multi-aged, old growth oak forest with snags (standing dead trees) and fallen dead trees in a range of diameters. The overstory is made up mostly of red oak, some yellow birch and occasional white birch; red maple is common but tends to be overgrown by oak. There are distinct subcanopies of moose maple at about 7 - 9 m (20- 30') height and witch hazel at 3 - 5 m (10- 15') and a continuous low bush groundcover, typically less than 60 cm (2') height. The groundcover is made up of blueberry, huckleberry, New York fern, bracken fern, lambkill, sasparilla, mayflower, Labrador tea (in pockets) and seedlings of red oak, red maple, moose maple, yellow birch, fir and occasional black spruce. We didn't see any pine. Balsam fir is common on the forest floor but, except in a few larger gaps, does not grow more than about 3 m (10') in height and then, apparently, dies.

The stand is about 50 ha in extent. A few tree corings indicate that the larger trees are well over 100 years of age. Some adjacent areas support younger oak stands with some but not all of the features cited above (notably they lack moose maple and there are few snags and fallen dead trees); evidently they were subject to regular burning and/or harvesting until relatively recently. The old growth stand appears to have escaped burning by being relatively isolated and surrounded by wetland. It is, however, subject to recurrent partial disruption ("gap formation") by wind driven and biotic processes. Tree top damage by wind continuously causes decay in the tallest oaks and these produce single tree light gaps and valuable habitat for a suite of snag dependent wildlife (e.g. cavity nesters, woodpeckers, owls, possibly flying squirrel). This process ensures a steady supply of dead wood and continuous regeneration of seedlings of the intermediate shade tolerant red oaks and yellow birch. This old growth forest is thus composed not of trees of several centuries old but of younger trees yet the forest has the same characteristics expected for typical old growth (downed logs, standing snags, uneven-aged tree distribution, small blowdown gaps). Because of the high turnover of trees through wind and decay, there is great value for wildlife in this uneven aged oak forest that has such a complex of dead wood in snag and downed log and snags.

Southeast of Lower Trout Lake, we found the large (old) red spruce Ralph had described. They exist largely as widely spaced individual trees in mixed forest or more densely in smallish groves over a total area of perhaps 50+ hectare. The trees tower above other species (fir, red maple, white birch, yellow birch, black spruce, pine). The forest floor is bouldery and close to 100% moss and lichen covered with low vegetation (e.g., sarsaparilla, snowberry) where the canopy is mostly closed, and higher vegetation (typically 1 m, dominated by huckleberry, bracken fern, cinnamon fern) in more open areas.

Many of the red spruce trees are in the range 0.50 to 0.84 m (20 to 33 inches) diameter at breast height. Such trees are large for Nova Scotia; Ralph Johnson in Forests of Nova Scotia (1986) commented: "Red spruce is a medium size tree at maturity, reaching 16 to 30 inches dbh and 70 to 90 feet in Nova Scotia at from 150 to 280 years of ageŠThe largest red spruce reported in Nova Scotia was 31.8 inches dbh." Interestingly, our ground observations indicate the tallest trees can actually be identified on Google satellite maps from the shadows they cast on the surrounding trees. (Before we went into the area, we had wondered whether those shadows were cast by pines but, by far, the majority of the tallest trees are red spruce.)

The Lower Trout trees will need to be dated but from the appearance of the forest floor which has very few large downed rotting trees, we are guessing that these massive spruce trees were part of a regrowth of a secondary forest that replaced the primary forest after it was harvested 150 or more years ago. Individual red spruce trees can live for centuries and their progeny establish under the shading canopy and replace the large trees when they blow down. Today there are ample small red spruce for replacement of the large trees and over time, we expect that a true old growth forest with many snags, leaners and fallen dead trees in various stages of decomposition would develop, of course only in the absence of harvesting or fire.

A large blowdown was observed in an area where there are also many stumps and cut logs, suggesting that recent thinning may have contributed to the blowdown. Occasional large red spruce also occur outside of the Crown land in dense, fir forest which was likely clear-cut in the not-too-distant past.

Many Nova Scotian forests have lost the natural correspondence of tree and site; the over-abundance of fir, poplars, wire birch and red maple in many forests clearly reflects clear-cutting and short rotation forestry. The beauty of the Lower Trout spruce woods and the old growth oak forest east of Oak Hill Lake lies in their connection with the original forests. In the absence of repeated fires and/or harvesting, red spruce would be the natural dominant on much of the moist, but well drained land of the Chebucto peninsula and oak on the drier hills. Thus, these two woodland types are links to the original forest in this area. They also show us the kinds of forest that could prevail over larger areas in the future if they are protected.

The fact that our small effort (a couple of days at each site) was so rewarded suggests that other old woodlands and special habitats or species are waiting to be discovered or rediscovered in the wilds of the Five Bridges Lake Wilderness Area. Perhaps readers know about some; if so, we encourage you to forward the information to Beth McGee, chair of Five Bridges Wilderness Heritage Trust.

Go to versicolor.ca/forest to view more photos of these sites.