Wildlife and their habitats are seriously disturbed by this practice
Back in the 1980s, while working as a provincial biologist, I was called by the organizer of an Atlantic teachers tour to ask if I could highlight a wildlife issue on one of their itinerary stops. The tour is an annual, forest industry-sponsored series of field trips for educators.
An issue came to mind. I had been asked by the Lands and Forest wildlife division to locate a forest with an abundance of white-tailed deer and moose, to assist in a density study being undertaken by a student at Acadia University. One site I found had a high concentration of both species, and I knew why.
Later that summer a bus full of teachers sat on stumps overlooking the countryside while I described the scene. Large blocks of public forest land had been cleared, the trees hauled to the pulp mill. A single forest block remained, surrounded by clear cuts. Many of the moose and deer in that last block were there because they had been displaced by the earlier harvests. The last block was scheduled to be cut the coming winter.
Back home that evening, my phone rang. A teacher on the tour was married to the head of the Lands and Forests research division and there was a problem. Summoned to head office the next day, the problem became apparent—I was the problem; not what was happening with the wildlife and the woodland.
It must be acknowledged that responsible forest management certainly is taking place—selective cutting, leaving some wildlife corridors, food and shelter.
Clearcuts are what have increasingly become a contentious issue in the minds of the public. So, from a purely ecological perspective, do large clearcuts negatively impact our wildlife?
Quite simply, yes they do. Wild animals, insects and plants are killed by large clear cuts. After the trees are gone, groundcover plants wither in the sun and parched soils. Most die. Soil animals, bacteria and fungi, vital to tree growth and health, overheat, shrivel and die.
More mobile mammals, reptiles and amphibians become refugees. They flee their former habitats, dodging predators like red-tailed hawks and crows as they search for new shelter and food in other forests. If they find new habitats, they discover others of their kind (red squirrels, for example) have already established territories there. There are no vacant lots in nature. Newcomers are treated as invaders. Territorial battles begin. Imagine somebody arriving to commandeer your home. Displaced individuals are most frequently driven off by residents. The banished, starving and lacking shelter, quietly die or succumb to predators.
Birds like ovenbirds nest on the ground in the middle of large forested areas. Finding the woodland gone, they may opt to nest in smaller woodlands bordered by clear cuts. Raccoons, crows, skunks, blue jays and other predators that hunt forest edges find and devour the eggs or young. It’s called the “edge effect.”
In spring and early summer, many birds nest in trees. Healthy forests include tall, older trees. Some bird species spend most of their feeding time in upper tree canopies. Others habitually feed in a middle canopy zone; still others in the lower. Finding their familiar forest cut and gone, they search for new habitats. Territorial battles erupt that they usually lose. Stress and a lack of food and shelter will eventually lead to death.
Migratory birds are protected under the federal Migratory Bird Act. However, people continue to ruthlessly mow down forests and nests throughout the breeding season.
A surprising number of wildlife species use holes in trees for shelter and rearing their young. Four species of ducks, snakes, mice, several owls, nuthatches, chickadees, tree swallows, flying squirrels, bats, kestrels, wild bees, seven woodpecker species and many other animals and birds depend on such tree cavities. Current forest management regimes leave a few, largely useless, clumps of trees in clear cuts. Suddenly exposed to wind, these frequently blow down after the harvest. Forests are currently being clearcut every 30-55 years, long before trees have grown old and developed holes for wildlife use.
Size matters! No wonder there are growing lists of forest species at risk in the region, from lichens to warblers to Nova Scotia’s mainland moose.
Many salamanders, toads and frog species mate in woodland pools, where fish are absent so eggs and tadpoles have a better chance of survival. A forest canopy moderates temperatures. Clearcutting dries up these ponds prematurely. Raccoons and others gather to feed as tadpoles become vulnerable. Puddles in machinery ruts become new breeding sites for amphibians and fatal traps when they, too, evaporate.
Large clearcuts create drastic ground level climate changes that few forest-dwelling wildlife species can tolerate. Shady, moist, comparatively cool environments under forests are suddenly open to direct sunlight, higher air temperatures and the drying effects of winds.
Rainfall is absorbed by leaves, needles, tree roots and damp soils. After clearcutting, heavy rains hit dry, hard ground that has often been compacted by heavy machinery. Runoff rushes over bare ground. Organics and nutrients leach from the upper soil layers and wash away. Instead of slow forest absorption then gradual release of water, clear cuts flush like toilets into brooks, streams and rivers, creating increased erosion. Stream banks, torn asunder by floods, topple trees that shaded the waterway. Soil carbon begins to migrate into the atmosphere.
Silt clogs spawning beds in stream channels, causing fish eggs to suffocate and die. After heavy rains repeatedly rip their way downstream, stream channels are left wide and shallow. Summer water levels become very low. Increased amounts of sunlight overheat the water, increasing evaporation and causing cold water species like salmon and trout to suffocate for lack of oxygen in the water. (For more information on how streams and rivers fall apart with poor land use, see Saltscapes Volume 1, No. 3, 2000, entitled “Cry Me a River”.)
And then there’s winter, when wildlife needs shelter. A forest technician called me several years ago after he located a young black bear that was hibernating in a depression—out in the open elements of a clearcut.
Overwintering white-tailed deer congregate in valleys and south-facing slopes less prone to prevailing winds. They need reasonably dense softwood cover for shelter, and adjacent areas with hardwoods and softwoods for food. Years ago, cutting winter hardwoods in a mixed wood stand for firewood at the farmhouse was a help to deer, as branches on the ground became browse. Now we’re seeing whole-tree harvesting, tops and all, in known deer and moose wintering areas.
We might argue wildlife species that share these forests with humans deserve more consideration.