Tree Stability

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Root Stability

The holy grail of tree assessment is to be able to say

“Yes that tree is safe”.

Few tree surveyors are ever prepared to go that far and of course, we can never fully predict the weather, but with the right assessment methods and weather models, it is possible to get very close and retain trees with reasonable confidence that even we would have condemned up until a few years ago.

The science of tree safety has come a long way from drilling, hammering and even kicking trees and although that will still do for some it is not sufficient for others

We believe that the management of a tree, particularly in these environmentally sensitive times needs to be made from a position of knowledge and this knowledge when it comes to trees relies on the combination of experience and accurate information.    

Dynamic Assessment – Dynaroot

Dynamic assessment of trees uses a combination of sensors attached to the base of the tree, enabling us to test the root anchorage. When wind blows trees start to move, and this load is transmitted into the ground via the stem and root. We use sensors to record the motion of tree in natural winds in addition to equipment that records the winds on or close to the site.

When the result of the sensors are compared, it enables the relationship between the prevailing wind and the response of the tree to be calculated and provide a safety factor for uprooting.

The motion of the tree shows the real response of a tree to the natural conditions and enables the identification of excessive movement and helps identify weak trees.

Static Assessment (Tree Pull Test)

The tree-pulling test provides information about the tree’s resistance to uprooting precisely and non-invasively.

In a pulling test, a measured load (substitute for the wind) is exerted on a tree using a winch and a steel cable. The reaction of the tree under this defined load is measured with high-resolution devices attached to roots (inclinometer’s) and the data obtained are compared with those of previously tested trees.

The response of the tree to the applied load enables the identification of excessive movement and helps identify weak or unstable trees.

Whole Tree Stability
Dynamic Assessment – DynaTree

Dynamic assessment of trees uses a combination of sensors attached to the base of the tree and the stem, enabling us to test both the strength of the stem and the root anchorage. When wind blows trees start to move, and this load is transmitted into the ground via the stem and root. We use sensors to record the motion of tree in natural winds in addition to equipment that records the winds on or close to the site.

The motion of the tree shows the real response of a tree to the natural conditions and enables the identification of excessive movement and helps identify weak trees and trees which have sufficient strength for the prevailing conditions.

Static Assessment (Tree Pull Test)

The tree-pulling test provides information about the breaking stability of the trunk and uprooting precisely and non-invasively.

In a Traditional pulling test, a measured load (substitute for the wind) is exerted on a tree using a winch and a steel cable.

The reaction of the tree under this defined load is measured with high-resolution devices attached to the stem and the roots (elastometer’s and inclinometer’s), and the data obtained are compared with those of previously tested trees.

The response of the tree to the applied load enables identification of excessive movement and helps identify weak or unstable trees.

Computer Modelling of Biomechanics      

This can be used on its own or combined with several of the above-mentioned testing methods.

Key dimensional information is used to compute tree stability factors, enabling the determination of the basic stability and likely impact of changes in the tree’s form and its response to site changes.

This can also be used to determine strength loss due to structural defects in the cross-sections of stems and branches in comparison to canopy size and expected wind loads.

Also, the method enables the evaluation of load reduction by crown remodelling/pruning to assess whether higher safety in damaged trees can be achieved whilst providing sufficient foliage cover to sustain growth.

WHAT OUR CLIENTS SAY

“Ian – thank you very much for you very good and thorough report”

PAROCHIAL CHURCH COUNCIL

We did a Health and Safety survey

“Having now read Ian’s thorough report I would like you to submit the application for removal of the tree”

MR H

Private client – We did a health and safety survey

“Thanks very much Ian – this is very comprehensive”

OPEN GARDEN

We provided a advanced tree assessment

“We have found this system to be very useful in assessing the health and therefore the management of some of our elderly trees”

KATHERINE MUSGROVE

Garden Manager – RHS Harlow Carr,  Harrogate ( We provided advanced tree assessments)

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