Level 1 Tree Inspection Course at Holt Hall
Field Studies Centre with David C. Dowson for Forest Schools Level 3.
Intro - 7 a day killed on roads, same as
number killed by trees in a whole year.
DD is from TreeLife Limited based in
Leicester, and TreeLegal Ltd and a member of the AA Arboricultural Association.
- Visually identify tree defects from the
ground using binoculars and using a mallet and or probe where appropriate.
- Record defects and rate hazards
- determine a course of action, typically
one of -
... get advice
... plan to get specific work done -
contractor or self if easy (low hanging branches).
Duty of owners and inspectors explained,
particularly with regard to "reasonable care".
Claus Mattheck's "Axiom of uniform
stress" - no weak point, no breakage.
Growth and competition: trees are 4.5 times
stronger than they need to be. Mechanically self-optimised structure which adds
material to repair damage. This makes visible bulges, which we can recognise if
we know what a "normal" tree looks like.
Sequoia sempervirens is often a good
example of normal.
We learnt to do a VTA visual tree
assessment systematic diagnosis.
Photos of 12 common defects were discussed
-Fruiting bodies of Inonotus hispidus on
-Compression fork with embedded bark
weakening a limb. A healthy tensile fork often has a ridge.
-Significant bulges can indicate hidden
problems, or just healthy healing. Normal may be tapered or cylindrical.
-Ivy can obscure problems and add to the
load due to wind and snow.
-Dead bark may indicate dead wood below or
-Slimes and fluxes are exuded for
-Deadwood can easily be seen when a tree should
be in leaf.
-Die back in the crown seen by discoloured
or missing leaves, early drop in Autumn or late buds in Spring.
-Cavities may be a weakness if greater than
a third the wood gone - will cause bulges nearby.
-Wilting and discoloured leaves.
-Cracks and splits
-Root damage by diggers