The Definition of Stress

For my main occupation I am an arborist.

It’s my job to arrange for the inspection of trees in order to manage them appropriately.

Trees are remarkable, self optimising structures.

A direct product of their genetics and environmental stimulus.

And when left to their own devices, can live for tens, hundreds and thousands of years without issue, supporting literally thousands of other life forms on one individual tree.

When we plant or encompass trees in urban settings, conflicts occur.

An urban environment is a stressful setting for a tree.

In arboriculture, the definition of stress is:

"A reversible condition where energy and other survival factors become limiting, and a system, or one of its parts or processes, begins to operate near the limits for which it was designed."

Alex Shigo

As an example, factors such as poor quality soil, drought or excessive pruning may lead to stress.

Strain is seen as:

"A non reversible condition resulting from excess stress, where the system or one of its parts or processes exceeds the limits for which it was designed."

Alex Shigo

Trees have finite energy that fuels their annual processes such as growth and reproduction.

They bank energy for emergencies like defence following an attack from a disease, or wounding from events like pruning or storm damage.

And their stored energy enables them to withstand certain events which are particularly energy demanding, like bud burst - the emergence of new leaves or flowers in the Spring.

Life as an urban tree is a challenge, and it is tribute to nature, and the evolution of trees, that any survive at all.

When managing trees, it is vital to consider the stress already placed upon that tree, to ensure any recommendations you make for management don’t push the system too far.

The same can be said for all living things, animals and plants, people, and our planet.

We all have finite energy to maintain our parts and processes, generated by essential elements, optimal conditions and rest.

And we can all succumb to excess stress, leading to strain - that non reversible condition.

For all living things there is a point of no return.

"Don't ask too much of yourself, or others."