Proper pruning, better sawlogs

BY ANDREW GRINDLAY

Winter is the best time of year to prune trees in the farm woodlot. The colder the weather, the less likely airborne pathogens such as insects or fungi will be flying around ready to enter pruning wounds. As well, in cold weather, the bark tends to be harder and less likely to tear when a branch is lopped off. Since callus (new tissue) growth occurs primarily during May, June and July, wounds made prior to May close rapidly; those made after July close little until the following May.

All trees being grown for lumber or veneer benefit from pruning - some more than others. A western forest researcher found that artificially pruned Douglas firs began to produce clear lumber rather than the knotty common construction grades in one-tenth the time required for trees to prune naturally. In Ontario, farmers find that they can get at least twice as much for a clear log than for one that has branches.

Black walnut, balsam fir, white pine and eastern hemlock are poor natural pruners. Since balsam and hemlock are used primarily in construction or for pulp and do not fetch a better price if they have been pruned, there is not much point to pruning them. But the value of black walnut and white pine can be increased significantly by pruning.

Beech, ash, maple, cherry, oak, tamarack and red pine tend to lose their branches by themselves, provided, of course, that the branches are shaded by surrounding trees.

Pruning has to be done properly or it will do more harm than good. Most important is to make the pruning cut just outside the branch collar, being very careful not to damage it. The branch collar is the raised part where the branch joins the tree.

A tree wound does not heal. The tree grows a callus over the wound, trapping inside any pathogens that might attack the tree. If the collar is damaged by a sawcut or by being flattened by pruning shears, it takes much longer for the wound to close and opens the time window in which pathogens can enter. The pathogens create rot, which attracts insects, which spread the pathogens further inside the tree.

Almost as important is to avoid leaving a stub when a branch is cut off. If a stub is left, the branch collar starts to grow the callus outward, away from the tree, eventually covering the stub unless it rots away first. Enclosed branch stubs create long spike knots inside the tree, which lower the value of the log.

Both dead and live branches should be pruned. In a woodlot the lower live branches get little light and therefore do not contribute much to the growth of the tree. They use all the energy they produce in their leaves just to maintain themselves, and can be pruned off with no damage to the tree.

Dead branches should be taken off because in some trees, such as white pine and black walnut, they cling to the tree for many years after they die. The branch collar starts the callus growing outward, just as with a stub, leaving plenty of opportunity for pathogens to enter via the rotting branch.

No more than one-third of the crown should be removed from the tree in one year. The tree gets its energy from the leaves and needs a large leaf area to create enough energy by photosynthesis to grow. And branches more than 2H inches in diameter should not be pruned; doing so leaves a wound that takes too long to close over.

To promote single leader growth and to create clear stems, pruning can start one year after the trees are planted. When the trees are small, hand pruners or pruning saws can be used. When the trees are tall, say over 30 feet, a pole pruner can be used.

To avoid tearing the bark below a live branch, first make a shallow cut on the underside of the branch about an inch out from the tree. A second cut should be made about 12 inches away from the tree, removing the branch entirely. The final cut should take away the stub, right next to the collar, but not damaging it.

There is no need to paint the wounds with anything. Painting does not help to close the wound or keep out pathogens.
Retired UWO business professor Andrew Grindlay is an avid amateur arborist

© copyright 1998 Agricultural Publishing Company Limited.


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AGRI-BUSINESS

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Nuts & bolts

Oil of emu Here's some brighter news for the Ontario emu industry, which struggles to establish new markets. It appears the American medical community is on the point of recognizing emu oil's health benefits, according to Terre de Chez Nous. At $11 per kg for emu fat and an average 15 kg of fat per bird, the oil adds extra value to the bird, and is already sold in health food stores for $14.95 per 30 ml bottle. The Quebec farm weekly also reports that Daniel Dean, a doctor from Michigan, has found emu oil hastens healing of eczema, burns and scrapes. Dr. Ernesto Hernandes of Texas A & M University has found the oil, which resembles vegetable oil, quickly penetrates the skin in treating muscular and joint ailments. Deere season It's not often that agri-business receives recognition in the wider world of business, but Grimsby and Regina-based John Deere Ltd. did last month. The company was one of six Canadian companies including Amex Canada and Honeywell to win a 1998 Canada Award for Excellence. The award, from the Etobicoke-based National Quality Institute, encourages the adoption of total quality in the private and public sectors. The institute cited John Deere Ltd.'s Total Quality Management program, begun in 1989 for the company's 235 employees. The aim was to focus on the customer, while monitoring outside suppliers. Monsanto AHP Talks have broken off on the agri-biz merger of the century: the proposed US$34-billion union of Monsanto and AHP, an American consumer goods giant. On the ag side, the single company would have had a lock on leading soybean herbicides Pursuit and Roundup. According to Terre de Chez Nous, there were rumours of personality conflicts at the top derailing negotiations. Officially, both companies would only say the decision was in the best interests of shareholders.

Rural RAM The data's rolling in from your yield monitor - now what? Machinery maker Deere & Co., and U.S. farm co-ops Farmland and Growmark are putting their heads and combined US$20 billion in sales clout together to find out. A three-way task force will examine developing a database allowing farmers to store, retrieve and analyze production data with complete security and privacy. E-beefs Now there's an electronic alternative to banging on the constituency office door. Federal Agriculture Minister Lyle Vanclief has launched a rural chat group on the Internet. As part of his Rural Dialogue cross-country workshops, farmers can e-mail their "concerns, opinions and priorities" about rural Canada to the government. "The government of Canada is committed to consulting the grassroots to identify ways to strengthen rural Canada," says Vanclief. To subscribe to the discussion group, e-mail the government at assadlo@em.agr.ca, putting "subscribe dialogue" for the e-mail subject heading. Take your picker It's a niche market, but someone's got to make special harvesters for farmers such as sweet and seed corn growers who need to harvest the whole ear. Two of the big names in the business, Byron Equipment of New York State and Pixall of Wisconsin, have merged to form a US$40-million company. As well as corn pickers, they make snap bean, lima bean and pea harvesters. Manufacturing will be consolidated in Wisconsin.

© copyright 1998 Agricultural Publishing Company Limited.


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UNEARTHED

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Notes from All Over

Rounding up rodents and journalists

Rodent control was the topic recently on an Internet discussion frequented by scientists wishing to remain on the cutting edge of the swine industry. One nutritionist dutifully weighed in with the method used on "about 20 per cent of the commercial farms" in his country.

"Where manpower costs are low and many people are under- or unemployed on a farm, one effective way to dramatically reduce a rat population is to levy a short-time bounty on the rodents. A one-week flurry of stone, stick and slingshot wielding hunters can yield quite a number of dead rats.

"The pigs are unaffected since the targets are usually in canals or storerooms, and stealth is required to apprehend [the rats]. A positive spinoff is the boost in morale provided by the community hunting campaign and the sure-to-be-enjoyed round of beer and Cokes purchased from the bounty and shared at the end of the hunt."

An informal, unscientific survey conducted on Toronto's transit system unearthed a lament among financial industry workers over the loss of the Financial Post's Canadian perspective on business news. The Post was folded into Conrad Black's new National Post newspaper Oct. 27, and one mutual fund manager noted that Black's daily now provides "the international perspective that I can get daily from the Wall Street Journal, but with less depth."

Farmers, no doubt, are itching for more accuracy - let alone depth - in the paper's coverage of Canadian agriculture. An Oct. 30 item claimed Quebec farmers took their flocks to Parliament Hill earlier that week in protest over government's refusal to provide compensation for sheep that had to be destroyed because of "infestation with scabies mites."

A second gem appeared Nov. 3, when a front-page story on antibiotic resistance informed readers that farmers spray antibiotics on crops.

Looking to earn some money from that bog in the back 40? Cranberries might be an idea, given recent findings by Rutgers University in New Jersey.

Terre de Chez Nous reports that researchers there have discovered that a 10-ounce glass of cranberry juice a day can reduce risk of urinary infection, which afflicts an estimated one-quarter of women.

Researchers found that a chemical compound in cranberries prevents the bacteria which causes the infection, Escherichia coli, from attaching to the walls of the bladder or kidneys.

If keeping the kids down on the farm is proving troublesome, the least you can do is point them to a career in animal science. They're likely to find work, says Dr. Rob McLaughlin, dean of the Ontario Agricultural College, University of Guelph.

McLaughlin told participants in the Farm Business Management Council's Agricultural Risk Management Conference last month that last year's animal science grads "had two or three jobs to choose from. "Last week," continued McLaughlin, "I had a major employer asking how second-year students could be hired. Jobs are not the issue. What is scary for me is that enrollment is down in ag science."

© copyright 1998 Agricultural Publishing Company Limited.


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