Archive for April, 2019

A is for Arboriculture and other A’s

Friday, April 5th, 2019

As short series of blog posts, we thought it might be interesting to our readers to go through our glossary and discuss the various technical terms which appear in our reports and discussions. Whilst common place to us in our industry they can be like a foreign language to our customers, so let’s start with the A’s


Abscission is the first to appear in our glossary and what a term to start with! Not unique to arboriculture, abscission is the term used to describe the shedding or disposal of a part of the whole, such as the dropping of leaves, berries or seeds. It is also the term used by zoologists to describe the intentional shedding of skin (reptiles), claws, tails etc.
Whilst Abscission can be a normal and natural consequence of the plant’s reproduction or seasonal cycle, it can also be a symptom of stress or defence. Early fruit drops can be a symptom of water stress and premature leaf abscission can be caused by a natural defence to infestation by gall aphids.
Abscission can be either normal or abnormal and abnormal abscission is a good indicator of poor plant health and should be a trigger to take a closer look.


Abiotic, pertaining to non-living agents; e.g. environmental factors, the inverse to biotic factors, examples of abiotic agents we are interested in are light intensity, temperature, soil pH, soil moisture, pollution to name a few. Many abiotic factors can influence the health and growth of a tree or group of trees. By identifying and observing abiotic factors impacting a specimen, we can more accurately predict the health and lifespan expected.


AAdaptive Growthdaptive growth and adaptive roots go hand in hand, adaptive growth is the rate of wood formation in the cambium (the area of wood directly underneath the bark, the most outer ring – see below) in a perfect location this will grow evenly around the tree, under stress or ‘abiotic’ influences such as wind, gravity, physical obstructions, this can grow non uniformly and cause stress to the tree.


Adaptive roots are beautifully illustrated here –Adaptive roots
The adaptive growth of existing roots; or the production of new roots in response to damage, decay or altered mechanical loading





Adventitious shoots are shoots that develop other than from the usual places such as apical, axillary or dormant buds. Sometimes used to the advantage of propagating gardeners to grow new plants from cuttings, examples are where you may see new growth forming on a leaf, or at both ends of a cut stem.


Anchorage is a well described term. The anchoring effect of the tree roots into the soil holding the tree firmly and securely. Poor anchorage can be caused by disease, lack of water, obstructions all of which can cause the tree to grow poorly or become unstable.


Architecture, like a balanced building each family of trees will have a distinct and predictable architecture, a balance to the structure of the tree and the reason for the clear and distinguishing outline of the mature specimen.


Axil, as mention in the adventitious shoots paragraph, the axil is where a bud may form between a leaf and it’s parent shoot. Not to be confused with a car axle


And that as they say is ‘A’ wrap, come back to see the B’s soon.

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