There are many amazing benefits to living in a city, but the city life can be hard on your trees. Urban soils are very compacted – they have to deal with high volumes of foot traffic, vehicle traffic and what seems like near-constant construction. This creates a difficult situation for your trees’ roots.
Roots need oxygen, water and nutrients in order to sustain a healthy tree. Unfortunately, compacted soil makes accessing those things very difficult. Compacted soil has very few pockets of oxygen, which also makes it difficult to sustain a healthy environment of microorganisms and nutrients. It also makes it more difficult to retain water. More water will runoff than be absorbed in compacted soil.
So, how do we help ease the compaction on your soil? We have a few tricks up our sleeves that make a big difference.
Soil Renovation & Vertical Mulching
Using a pneumatic Air Spade tool, we open columns in the soil all around the root zone of the tree. The air spade tool breaks apart the soil without causing damage to existing root systems, utilities or other in-ground infrastructure.
The columns are then back-filled with our custom compost. Our hand blended compost is formulated with humates, volcanic minerals, pH adjusters and organic material. This compost stimulates biology, improves disease resistance, maintains open pore spaces and creates an ideal environment for healthy root development.
We can now also include Biochar as part of our soil renovation service. Biochar is an amazing tool for fixing depleted and compacted urban soils – it acts as a sponge drawing in nutrients and holding onto water for your tree roots to access. Also, because it decomposes at such a slow rate (hundreds to thousands of years), the soil will not re-compact around the Biochar, keeping those wonderful pockets of oxygen, water and nutrients available to your tree.
Soil Aeration Tubes
Another great way to mitigate compacted soil is to install soil aeration tubes. The installation process is similar to the soil renovation process. Columns are created around the root zone with the air spade tool. However, instead of back filling with compost, a wider column is created and an aeration tube is installed into the column. The lid of the column rests at grade so it is not a tripping hazard. The tube is perforated to allow for oxygen and water to get through.
The main function of the aeration tubes is to promote easier air and gas exchange to the root system of the tree, which encourages healthier root development.
The tubes also conserve water by allowing direct watering to the roots, eliminating runoff caused by conventional irrigation or sprinklers. These tubes also collect natural rain and any runoff from storms directing it directly into the tubes down to the root zone.
Aeration tubes are a great option for trees planted in areas with little soft scape, like patios with interlock.
Once you’ve renovated your soil and/or installed your aeration tubes, make sure to get a treatment of ArborGain™ and Mycorrhizae for your soil. ArborGain™ is full of active bacteria and micronutrients to help your soil come alive and to sustain the soil organisms that you tree roots need to thrive.
Keep your trees healthy and beautiful by starting from the ground-up! Talk to your arborist today to see if your soils could benefit from some de-compaction!
Be Good to Your Trees!
Kristie Nairn, MA, MMst
Cohen & Master Tree and Shrub Services Ltd.