It may be the middle of winter now, but spring is just around the corner. That means tree planting season. The value of mulching around tree plantings, particularly with wood chips and woody mulch, is well documented, but there is more to wood chip science than meets the eye.

Wood-based mulches at the local retail store come in all shapes and sizes, including bark and wood chip mulches in different colors and sizes.

The most available and often least expensive wood mulch may come in bulk from trees and stumps that were chipped in your own pasture or yard, or in the neighbor’s fields and farms. These bulk mulches often contain bark, wood, and needles or leaves.

The mulches will vary in size, shape and composition, creating a more diverse environment for insects and microorganisms. According to Washington State University Extension, such mulches decompose slowly, supplying nutrients to the system and absorbing water that is slowly released into the soil. That makes these types of woody mulches superior in helping new tree and shrub plantings establish.

Woody mulches provide significant weed control around new tree plantings. Plus, they provide soil cover that prevents erosion and holds moisture in the soil surrounding roots of young trees. The mulches even out soil temperatures, so the soil warms up slower in the spring — allowing the tree roots to warm slowly as well — even when there are extreme cold weather events.

In addition, woody mulches slow the cooling of soil temperatures in the fall, allowing the tree more time to prepare for winter.

Sometimes woody mulches get a bad rap because of widely spread myths about their negative effects. To set the record straight, coarse-textured wood mulches in particular offer no fire hazard. Wood mulches do not attract pests such as termites, and some wood mulches of cedar — for instance — may help repel some insects.

They won’t tie up nitrogen and starve nutrients from trees and shrubs, WSU sources say. While woody mulches can prevent weed seeds from germinating around the tree plantings, they generally have no allelopathic impacts on trees and shrubs.

If you are planning to install woody mulches around new tree plantings, be sure to start early in the season before weeds begin to germinate. Clip or remove any aggressive weeds in the mulching area to help the mulch layer stay ahead of the weeds.

Apply the mulch layer at a depth necessary to prevent weeds and promote soil health. However, make sure the mulch is not too deep and mounded up around the tree trunk. Once the mulch is installed, it is a good idea to pull the material away from the trunk of the tree and taper it down to prevent excessive moisture and a low-oxygen environment around the tree trunk.

Over time, the woody mulches will decompose, so new layers of mulch will need to be reapplied to maintain usefulness. As more and more tools become readily available to devour invasive red cedar and brush from pastures, the availability of bulk woody mulches increases.

It is wise to utilize these mulches around the farm and ranch when you need them to improve the successfulness of new tree and shrub plantings.