UNIVERSITY PARK, Pa. -- When it comes to buying trees, a Penn State horticulturist suggests consumers treat a tree purchase with the same care they would use when buying a new car--after all, chances are the tree will be around longer than the car.
"While an ornamental tree is nowhere near the price of a new car, you can save time, money and frustration by making sure your new tree is top quality," says J. Robert Nuss, professor of ornamental horticulture in the College of Agricultural Sciences.
Nuss suggests inspecting the tree's general appearance first. The trunk should be reasonably straight and the crown of the tree should be symmetrical.
"When you closely examine the crown, no branches should extend from the trunk at angles less than 45 degrees," Nuss explains. "Narrow branch angles can cause structural problems as the tree grows."
Close observation of the tree's trunk can reveal problem areas that are easily recognizable, even to the greenest of gardeners. He suggests shoppers look for:
Damage. Check for signs of cuts, scrapes or recent pruning. "A wound that is more than a quarter of the trunk's circumference is too large and can affect future health."
Flaws. Look for areas that are discolored, sunken or swollen, all of which indicate problems beneath the bark.
Borer damage. "Check for small circular holes in the bark," Nuss says.
Cracks. Frost damage can result in shallow cracks in the bark.
Nuss adds that the general size of the tree can be an accurate indication of quality. By measuring the trunk diameter at six inches above ground level and the size of the root ball, shoppers can estimate how tall the tree should be.
Nuss offers some general guidelines to estimate tree growth and health:
- A trunk diameter of 1 1/2 inches translates to a tree between nine and 13 feet tall. The root ball should be at least 20 inches in diameter.
- A trunk diameter of two inches translates to a tree between 13 and 15 feet tall. The root ball should be at least 24 inches in diameter.
- A 3-inch trunk diameter should be found on a tree between 14 and 16 feet tall. The root ball should be at least 32 inches in diameter.
The size of the root ball should be roughly proportional to the crown, or area of branch spread, of the tree. "If the root ball is too small, it may not have enough roots to establish the tree," he says.
"Also, feel the surface of the root ball on trees that have been balled and burlapped," Nuss advises. "The root ball should be firm and solid. Check for pruned roots and girdling roots, which are roots that wrap around the lower trunk. Girdling roots are often found about half an inch below the soil line.
"Once you buy the tree, it's important to care for it," Nuss says. "Plant it as soon as you get home. If that's not possible, make sure to keep the root ball out of the sun and keep the burlap moist."
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EDITORS: For more information, contact Robert Nuss at 814-863-2196 or John Wall John_Wall@agcs.cas.psu.edu 814-863-2719 814-865-1068 fax