Tree Talk

TREE STABILITY: Dynamic Assessment & PULL TESTING

Dynamic Assessment: Tree dynamic assessment utilises a combination of sensors attached to the trunk and stem base. This approach allows Curley Consultants to evaluate both the trunk’s strength and the root anchorage. When the wind blows, trees begin to sway, and this movement is transmitted into the ground through the trunk and roots. Sensors are attached to the tree to measure the motion under natural wind conditions, and they record wind data at or near the site.

By analysing the tree’s motion, we can observe its actual response to environmental conditions, which helps us identify excessive movement. This information is crucial for pinpointing trees that may be weak or retaining those that possess sufficient strength for the prevailing conditions.

Static Assessment (Tree Pull Test)

The tree-pulling test offers precise and non-invasive information about the trunk’s breaking stability and the potential for uprooting.

In a traditional pulling test, a measured load, simulating wind, is applied to a tree using a winch and a steel cable. The tree’s response to this defined load is monitored with a high-resolution device attached to both the trunk and the roots, such as elastometers and inclinometers, and the data is collected and analysed. By analysing the tree’s reaction to the applied load, excessive movement and weak or unstable trees can be identified.

When checking your trees, there are several important factors to consider.

At this time of year, leaves are starting to emerge. Compare your tree to others of the same species in the area — are they developing at the same rate? If not, this may indicate that your tree is stressed.

Once the leaves have developed, examine the crown of the tree. Does it appear “full,” or are there noticeable gaps? A sparse crown can be a sign of issues.

Next, inspect the tree’s trunk for any holes or cavities, such as those made by woodpeckers. Look for signs of fungus on the tree as well. Check for any cracks in the soil around the base of the tree. Additionally, observe if the tree is leaning, instead of standing completely vertical.

If you are unsure or want a specialist to check your trees, contact Steve at Curley Consultants.