Category: Soil

Soil Compaction is a common contributing factor to tree stress and tree decline in our urban landscapes. It can be a problem that cumulatively develops over long periods of time, with effects that are often misdiagnosed.

Soil compaction occurs when the compression of the ground soil particles force the spaces between the particles too close together. This creates a soil environment that has little to no pore spaces available for needed water and air to reside in.

Soil compaction can physically damage or physically crush the roots of trees as well, as seen in high traffic pedestrian areas, and construction zones where heavy equipment is used around the base of trees.  “Shallow-rooted” trees for example, Spruce and Pine trees are sometimes more affected.  As with most trees, the absorption roots and root systems are within the top 12” of the soil.  When the ground is wet, soil compaction can become  a more rapidly increasing problem if traffic or pedestrian areas are heavily used, at that time.

There are, however,  a  few steps that  can be taken to help your trees and any further damage to the rootzones, due to “Soil Compaction”.

Firstly, Improving the soil “structure” by introducing compost or organic material can be helpful.  This will improve drainage, aeration, and contribute added nutrients for the tree.

Secondly, using a top dressing over the root zone of the tree with Mulch.  This will  also protect the root zone, by creating a buffer zone .  Mulch should be applied from near the trunk outward to the tip of the furthest branches of the canopy. This circumference under the tree is known as the “dripline”.   This area encompasses the  general area where the absorbing roots reside.  Although, some tree species can have rootzones   that are 2-3 times the spread of the canopy.  Your Edmonton Arborist can discuss with you about the benefits of using an organic mulch, such as bark or wood chips.  These mulches will aid in adding nutrients to your tree’s roots as it breaks down.  Mulch should not be applied more than 2-4 inches deep over the root zone.  If it is deeper, it can be detrimental to the roots by causing a suffocation affect.  Also, water, nutrients and air, can not effectively penetrate the area.

Lastly, “Soil Compaction’s” affects are often misdiagnosed,   showing symptoms of secondary  causes.   This is because it is not readily visible, or apparent to the untrained eye.  Trees can rapidly decline past the point of no return, if compaction continues or worsens.

It is important to have a Certified Arborist  in Edmonton assess and provide a site visit to determine the best management practices with regard to your soil, trees and landscape.