Written by Bob Villa and published on https://www.bobvila.com/.
Root collar excavation is the process of removing the dirt from around the trunk of a tree to inspect the base. This is done to investigate the extent of decay that is present or to view the structure of the roots to see if there may be a girdling root issue. Girdling roots are tree roots that have been misdirected and grow around or across the tree trunk causing tree health issues.
Often, if homeowners are seeing issues with the leaves or branches of the tree, it is a sign to inspect the roots. If the tree was planted too deep, the roots cannot get the oxygen they need and therefore grow around the trunk of the tree, ultimately suffocating it. This is what is referred to as girdling roots. Although the tree will still grow, it will not be as strong. Root Crown Excavation is used to thoroughly examine roots and determine the best plan of action to get your tree healthy and thriving once again!
Why the Root Collar is Important
“All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost.”
― J.R.R. Tolkien, The Fellowship of the Ring
As many have noticed, we have been doing some work to the trees along the entry drive. Amazingly, up to 85% of a tree’s root system dwells in the top 18 inches of soil. This makes trees particularly vulnerable to soil compaction. As we mow the lawn, heavy equipment passes over these roots repeatedly over the course of the spring/summer/fall. When you think of all the years these trees have been standing, that is a lot of pressure on their roots. To alleviate that pressure, we decided to mulch around the base of the trees (ideally, you would mulch all the way out to the drip line, but due to the size of our trees that would leave us with one big strip of mulch along the driveway). Mulching keeps equipment away from the roots as well as eliminating the need to use a weed wacker to get stray grasses near the tree’s trunk tidied up. Even the best intentioned groundskeepers (this one included!) have accidentally done damage to a tree’s bark with a weed wacker. Repeated weed wacker damage to a tree’s bark can result in something called girdling. Girdling is when the tree can no longer move water and nutrients up and down the bark because of this damage.
If soil compaction and girdling weren’t enough, we also had some concerns about the roots around the base of the tree. So, we decided it was time for a root collar excavation. A root collar excavation is a procedure in which a tool called an air knife is used to blast the soil out from around the base of a tree to give us an idea of what the tree’s uppermost roots are doing. In some cases, a tree can be planted too deep, and when that bark is buried it is susceptible to rot (and, thus, will girdle the tree). In this case it’s the roots that can be girdling the tree by tightly growing around and around the base of the tree. We want our roots to spread out from the tree far and wide.
Mulching also eliminates the grass from around the base of the tree. We all know grass likes lots of water. Now that the grass is gone, more water can be accessed by the tree’s roots.
Thank you to all who brought in newspaper. A layer of newspaper under the mulch helps smother the grass without mechanically ripping it out. Not physically ripping the grass out saves on labor and also helps the trees. All that digging and chopping can do damage to those sensitive roots.
Once we completed the mulching (and took a break!), we treated the trees to an application of compost tea. Compost tea is a wonderful concoction of high quality compost which is aerated (water is added to the compost and air is pumped through the mixture for 12 – 24 hours). This compost tea is alive with soil microorganisms. Once in the soil, these microorganisms help the trees (and any other plant it was applied to) retain water and take up nutrients from the soil.
Finally, we will research some groundcovers to fill in these mulch beds. Unlike grass, groundcovers can actually work in harmony with the trees – they support the same kinds of microorganisms in the soil that help with water retention and nutrient uptake. The soil under our feet is a remarkable living thing. By encouraging soil health and eliminating chemical fertilizers/pesticides, we can reap the rewards of a system in balance and enjoy these trees for many years to come.
Original post here https://www.bobvila.com/slideshow/7-signs-your-tree-is-dying-and-how-to-save-it-53337#carpenter-ants-feeding-on-dying-tree.
