Soil Compaction

In most urban and suburban areas suffer from soil compaction, typically due to construction or high traffic which is why soil management is so important. For example in forests, the top 6 inches of soil is 50% oxygen. However; the average urban soil is only 10% oxygen. This lack of oxygen and pore space doesn’t allow enough water, oxygen, or nutrients to reach the tree’s roots. This can create problems for root growth and the health of the tree overall just take a look at the photo below.

Symptoms & Signs of Compaction:

  • Overall decline in the tree’s health
  • Canopy dieback (deadwood)
  • Yellowing leaves
  • Early leaf drop
  • Early color change
  • Poor growth
  • Presence of Secondary invaders(insects & diseases) especially Borers
  • Areas under the canopy where grass doesn’t grow

Soil Compaction

Soil Compaction Leads To:

urban trees 1Lack Of Nutrients: Trees are living organisms and require nutrients to grow and survive. When soil is compacted there isn’t enough room for nutrients to reach the roots. This level of compaction will cause your tree to start showing nutrient deficiency signs such as yellowing leaves, early leaf drop, and poor growth.

Lack Of Water: When soil is compacted there isn’t enough room for water to easily penetrate the ground. This means that even if there has been lots of rain, the moisture may not have been reaching the roots. This level of compaction will cause your tree to start showing drought symptoms such as, wilting & curling leaves, yellowing leaves, decline in vigor, and leaf scorch (brown outside edges or browning between veins).

Healthy Soil (Non-Compacted, Nutrient Rich Soil):

  • Promotes plant and root growth
  • Controls the formation of toxic materials
  • Promotes growth and activity of micro-organisms
  • Controls the development of plant diseases

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How To Fix Soil Compaction:

Soil Compaction
Vertical Mulching

Aeration: To combat compaction we use high-velocity air tools and techniques to properly aerate the tree’s critical root zone (CRZ) loosening/de-compacting the soil. This creates macro and micropore space (space underground), making room for root growth and space for old roots to breathe.
DON’T confuse this type of aeration with the “aeration” machines sold at local hardware stores or completed by landscaping companies. These types of aeration only fractures the top inch or two of soil. This is beneficial for grass growth but it is not deep enough to benefit your tree’s roots. Our aeration will get down 4-6 inches de-compacting the soil surrounding the tree’s roots.

Vertical Mulching: If your tree is suffering from nutrient deficiencies as well as compaction, our arborists may recommend Vertical Mulching as a form of soil management. This process is similar to Aeration but goes one step further. Vertical mulching uses the same high-velocity air tool, as Aeration/de-compaction does, but the technician creates holes every 2 to 3 inches out to the dripline of the tree. These holes are then filled with organic matter which permeates improves the overall composition.

Root Collar Excavation: When your soil has been compacted for long amounts of time, roots can start to grow higher than they should and wrap around each other. This is called girdling roots. When trees are showing signs of possible girdling roots, our arborists will most likely recommend a root collar excavation. In this process, we will use high-velocity air tools to blow away the soil and expose the roots. This then allows the Arborist to diagnose the tree’s root issues and describe what management is needed.

How To Prevent Soil Compaction:

Soil CompactionMulching:  One of the best ways to prevent soil compaction is to properly mulch. Mulching will help insulate the soil providing a buffer from extreme temperatures, prevent soil compaction, accumulate & keep more nutrients in the soil, and retains water keeping the roots moist during hot weather. It will also discourage people from walking over the tree’s roots.

Don’t Drive Or Walk Under The Tree: One of the main reasons soil becomes compacted in the first place is because people frequently walk or drive over the critical root zone. A trees critical root zone (CTR) is a circle that corresponds with the dripline of the tree (how far out the tree’s branches go).  Keeping this area undisturbed is one of the best ways to prevent soil compaction.

Water: When soil experiences a drought it can become crumbly and compact. Keeping the soil hydrated will keep this from happening. However, don’t rely on sprinklers to do this job. Over time sprinklers can beat down on the soil slowly causing compaction it as well plus they only hydrate to top few inches of soil. To be effective use a soaker hose or a hose on a slow trickle over a couple hours to water the soil deeply.

Bio-Stimulants: Proper nutrients in the soil, help prevent soil compaction and stimulate healthy root growth. Bio-stimulants are one of the best ways to ensure proper nutrients. This organic mixture contains a natural blend of sugars, bacteria, humic acid, sea kelp extract, and good fungi. The mix is great for soil management because it naturally fertilizes the tree without throwing off the balance of the soil. By introducing this blend to the soil it will re-establish good soil composition and act as a multi-vitamin for your tree.

Learn More About Soil & Root Health