How Does That Work?

OPPD Arboretum puts tree trimmings to work

The beauty of the OPPD Arboretum reflects the care and maintenance it receives on a regular basis.

The mulch that results from tree trimming is key. A contractor runs the trimmings through a wood chipper to make the mulch, said Mike Norris, OPPD forester.

Each year, about 480 cubic yards, or 40 truckloads, of mulch are applied to the 1,000 trees and shrubs at the arboretum located at 108^th and Blondo streets.

“We mulch trees and shrubs year round as needed,” said Norris. “But the majority of trail and large mulch bed work is done through the off-season (November through February).”

Norris added that most of the wood chips come during late fall and winter when trees don’t have leaves. This produces a better quality mulch, he said.

Mulch provides several benefits for plantings at the arboretum. These benefits also translate to your home’s landscaping. Among them, mulch:

• Maintains soil moisture
• Protects the trunk and some surface roots from mowers and string trimmers
• Helps control weeds and grass
• Insulates the soil’s surface, keeping it warmer in the winter and cooler in the summer
• Improves soil structure, aeration and drainage
• Increases soil fertility as the organic matter decomposes

Norris offers the following advice for homeowners on how, when and why they should utilize mulch:

• Along with wood chips, you can use other organic mulches, such as pine needles, shredded bark, compost mixes and leaves.
• Apply a two- to four-inch layer of mulch out to the drip line. Don’t pile mulch against the trunk.
• Pull mulch back several inches from the trunk. This will expose the base of the trunk and the root crown. Mulch placed against the trunk can lead to insect, disease and rodent problems.