06/01/2026
Let me tell you a story about the little tree that 'wood'... 👀
Trees have 2 kinds of roots 'structural roots' and fibrous roots, both of which start developing from first sprout. These roots are designed to both absorb nutrients from the soil and anchor the tree into the landscape.
If a tree is planted in a hard-walled pot, the roots extend outwards and eventually hit the pot wall and circle / girdle around the pot, head straight down the inside wall of the pot or 'J' turn inside the pot as they can't extend out as they would in nature.
Research has suggested that tree roots may have a memory whereby they can continue with this growth pattern throughout the tree's life. The problem with this is when the tree is planted, and not planted correctly to rectify the issues, it can result in a root system that rather than replicating nature and extending the roots outwards to anchor the tree into the landscape, the root system continues to circle and girdle. The tree's root system is compromised and can result in reduced stability increasing the risk of whole tree failure. The health of the tree can also be impacted as the root system can strangle the trunk restricting the access of nutrients to the tree resulting in the premature decline or death of the tree.
Here at Tree Sales, our trees are grown in air-pruning pots. These pots are designed to replicate natures processes with root growth. When the roots reach the edge of the pot the roots are exposed to air and light and naturally prune, developing a more fibrous root structure. When planted, these trees have a more fibrous root system able to access water and nutrients from the landscape necessary for the growth of the tree and set the structural root plate in the landscape, adapting to the weather conditions and reducing the risk of whole tree failure.
So when you are picking a tree from a nursery, look for roots on the surface of the root ball, the absence of roots could indicate that the tree has been transplanted too deeply exposing it to the risk of collar rot. Also look at the trunk caliper (it should appear thicker towards the base where the structural/buttress roots will establish from) and taper up so that the trunk 'thins' as you look up the trunk. Pull the root ball out of the pot and look at the roots, are they heavily circled or girdled around the outer region of the root ball?
Where possible avoid roots which appear distorted and tangled as they indicate that the roots in the pot are circling and girdling which will shorten the life of your tree by restricting the flow of nutrients to the upper canopy as it grows.
