Tree huggers think clear-cutting is a sin, but woodlot foresters say it’s sometimes the right thing to do.
“There’s basically two stand types in southern Manitoba,” Carol Graham, a MAFRI woodlot forester based in Souris, said at a recent presentation at the Forester’s Memorial Hall in Baldur.
“The one that’s most prevalent is an even-aged stand, typically of a single species, predominantly aspen and poplar, or jack-pine and black spruce as you move into northern Manitoba.”
Clear-cutting even-aged stands – such as aspen and poplar bluffs – mimics nature, specifically Prairie fires which used to periodically sweep through these small pockets of forest. (The other type of stand is made up of multiple species of different ages, and can include hardwoods such as oak, ash, and maple mixed with softwoods. Clear-cutting is not the best harvest strategy for these stands.)
Mimicking a fire event usually involves clearing out mature trees in blocks of at least two acres. The leftover slash piles and strewn branches may look ugly for a year or two, but once the canopy is broken and the sun warms the soil, reserves in the root systems send up suckers that quickly develop into new trees and the cycle begins anew.
“Throughout their lifetime, they maintain a uniform height, maturity, and stem structure,” said Graham, adding such stands generally reach peak productivity at about 60 years, and then decline as disease, insects and shrubs move in.
“The reason is that these are species that don’t like competition and want the whole space to themselves,” she said. “They don’t like sharing nutrients or moisture.”
In southern Manitoba, most aspen and poplar stands are overmature, and “going to pot,” she said. This can be seen in virtually impenetrable under-storey growth that drives out deer; prevalence of rot caused by fungal infections such as false tinder konk; and insect infestations.
It’s a natural progression – overmature bush is just waiting for fire to push its reset button.
Such stands have little harvestable timber, and generally only yield firewood. Clear-cutting is best done in winter when energy reserves are in the roots, and the soil is frozen to minimize ruts from heavy machinery.
In uneven-aged stands, especially those with hardwood species, responsible harvesters employ a different strategy focused on opening up gaps in the canopy. Removing dead, diseased, deformed or dying trees gives better trees that have more room to grow. In a 10-year span, growth rings show properly managed oak trees can grow by an inch and a quarter in diameter at the stump, compared to half an inch for those trying to crowd each other out.
To encourage landowners to make better use of their woodlot resources, the provincial government offers forest BMP (Beneficial Management Practices) incentive grants.
In the last three years, landowners with a total of about 110 acres have taken advantage of the program (for more, see www.gov.mb.ca/agriculture/woodlot).
“We’re trying to encourage landowners to go out and manage their woodlots,” said Shawn Dias, a woodlot forester from Somerset.
As most are overmature, the first stage involves removing dead, diseased and dying trees for firewood. Strategic cutting to reduce competition follows in the second stage, while felling of top-quality saw logs is done in the third.
Woodlot owners or loggers who have gone through a one-day basic course in felling techniques and saw safety and sharpening, as well as a two-day session in low-impact logging, are eligible for grants of $390 per acre for a seven-acre woodlot, for a maximum of $2,730. Courses are usually held in fall, and cover bucking and skidding with tractors, ATVs and horses.
“The incentive dollars are aimed at covering the operating costs of the logger, because really we’re asking them to come in and take out all the junk,” said Dias, adding the program also offers a template for a timber sales agreement.
If the landowner does the work, he or she gets to keep the firewood and the money.
“On average, I’d say there is about 30 to 60 cords of wood coming out of these projects,” said Dias.
Woodlot foresters first visit the site and conduct a woodlot
management plan with a full inventory of what’s there, and later return for a post-harvest inspection. Infill planting may also be done where necessary.
Contrary to popular belief, low-impact logging is generally an acceptable use of land covered by conservation agreements, said Al Bourrier, a Manitoba Habitat Heritage Corporation representative based in Killarney.
Agreements can be altered by “mutual consent,” he said because it’s recognized woodlot management can improve wildlife habitat.
“You might be thinking to yourself that you can’t do a woodlot management plan if you’ve signed a conservation agreement because it says that you can’t clear, but we can work with landowners and issue a permit so that they can go ahead,” said Bourrier. daniel. [email protected]
“Thereasonisthatthesearespecies thatdon’tlikecompetitionandwantthe wholespacetothemselves.Theydon’t likesharingnutrientsormoisture.”
– Carol Graham