Just over a month ago, a powerful, fast-moving storm brought down more than 6,000 trees in the Chicago area. With the damage cleared away and the stump finally ground out, it may be time to replace a lost tree in your yard.
But before you automatically plant the same beloved species, give it a hard think. There may be a better tree or a better spot. So even though fall is a good time to plant trees, take time to make a good choice. “It’s going to be part of the family and someone you’re going to live with for a long time,” says Edith Makra, community trees advocate at The Morton Arboretum in Lisle.
Here are some of her tips for choosing and planting a replacement tree.
* Allow enough space. It is easy to forget that a skinny little sapling can grow up to be 50 or 60 feet high and wide, and we may become so accustomed to its presence we don’t notice it getting large enough to loom. But a tree too close to the house can not only block light to windows and obstruct the front walk but undermine the foundation and threaten the roof in storms. So plant a tree with enough room for the size it will reach at maturity, years hence.
* Be open-minded. Emotions run strong, but it may be unrealistic to expect another tree like the one you loved before. That one may have started growing 200 years ago, before Chicago, when the soil was not compacted or paved and its roots had room to roam; a new one like it might never get going. And of course, with Dutch elm disease and emerald ash borer, it would be folly to plant another American elm or ash. So step back, think about what your site is like now and what you want from a tree — shade, screening, fall color — and start fresh.
* Look up. Are there power lines overhead? “Nobody likes the power company to come through and hack trees,” Makra says, but if we plant them under power lines they must be trimmed for safety and to reduce the danger of outages. If you must have a screen there, plant a short variety that will never grow big enough to need trimming.
* Form matters. Trees are strongest if they have a straight central stem or leader. And branches are most vulnerable to stormy winds if they join the trunk at an acute angle. So the elegant vase shape of an elm “comes at a bit of a price,” Makra says, making it crack easily, while an oak with a central trunk and right-angled branches is very strong. Every young tree needs shaping to make sure it has good form later on, Makra says, and it’s worth it to hire a pro. Regular pruning — every three to five years — pays off in health and safety.
* Faster is weaker. Fast growers such as silver maple, cottonwood, Siberian elm and willow tend to have weak, easily cracked wood. Many species with a perfectly reasonable growth rate are much more durable.
* Don’t buy problems. Avoid aggressive trees such as Norway maple and ailanthus that create weeding hassles.
* Bigger is not better. It may seem to make sense to plant a larger tree so you get a big tree faster. But Makra says it doesn’t seem to pay off in the long run. The larger a tree specimen, the more of its root system must be cut off to move it. If it survives, its growth will halt until it has regrown those lost roots. A younger tree, which keeps more of its roots, has a much better chance to live and will recover and start actively growing far more quickly; at the end of 5 or 10 years it likely will be at least as large as the older tree. And it will be a whole lot cheaper.
* Do replant. It’s not just beautiful; a tree makes the world better. And if you have enough clear space for them, large trees are best. They have more leaf surface area to cast shade, block winds, take surplus carbon from the atmosphere, generate oxygen, filter particulate air pollution and absorb storm water. Maximum energy savings come from a major shade tree planted on the west side of the house.
What’s a good shade tree? Depending on your site, Makra says, species to look at include Freeman maples such as ‘Marmo’ and ‘Autumn Blaze’; Kentucky coffee tree; hackberry; tulip poplar; swamp white oak; bur oak and chinkapin oak.
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How to mulch
New or old, any tree benefits from a layer of mulch over its roots. It holds in moisture; insulates against summer heat and bitter cold; adds nutrients and helps the soil structure as it breaks down; protects the soil from pounding foot traffic; eliminates competition from grass; keeps lethal lawn mowers and string trimmers away from the bark; discourages planting that could damage tree roots; and looks spiffy.
Mulching a tree takes just a few minutes, but you have to do it right. Bad mulching can do a tree more harm than good.
1. Choose organic mulch. Anything made from plants will be fine for the tree, but leaf mulch or finely shredded hardwood will break down faster and need to be replenished more often than bigger chunks of wood or bark.
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2. Don’t pile it up. You are protecting the roots, not the trunk. Heaping mulch against the bark can kill the tree by trapping moisture that leads to rot or harbor damaging rodents, insects or diseases. Instead, keep the mulch a few inches from the bark. Make sure the flare from the roots to the trunk is exposed.
3. Even it out. Spread mulch 3 or 4 inches deep in a flat circle around the trunk; a thicker layer is not better. Three 2-cubic-foot bags are a good start for all but the largest trees, but the wider the area of roots you protect the better. Don’t bother removing the grass first. It will die under the mulch.
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Learn more
Here are some sources for help in choosing a new tree:
* The Morton Arboretum, off Illinois Highway 53 at Interstate Highway 88, Lisle; 630-719-2424 or www.mortonarb.org/main.taf?p=3,2
* Chicago Botanic Garden, 1000 Lake Cook Rd., Glencoe, 847-835-0972 or www.chicago botanic.org/plantinfo
* University of Illinois Extension Tree Selector, www.urbanext.uiuc.edu/treeselector (this item as published has been corrected in this text)
* International Society of Arboriculture, www.treesaregood.com
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ebotts@tribune.com
