Fungi

Fungi are an interesting sideline to arboriculture. They are important to arborists as they often affect the stability of trees, by degrading the wood. They can however be beneficial to trees in the form of mycorrhizal fungi. Fungi also recycle woodland debris, creating the future soil and providing minerals and nutrients for the existing plants.

Some species cause catstrophic failure of trees- Ustulina for instance on beech, whilst others are known as twig pruners- such as Stereums on oaks.

Some species live on deadwood, recycling woodland debris. These are known as saprotrophes.

Mycorrhizal

Mycorrhizal fungi are important to plants as they attach themselves to roots of trees and then give the tree water and nutrients in return for sugars and starch from the tree. This symbiosis is important because the tree will not need to waste energy putting out feeder roots as mycorrhzal symbiosis can be ten times more efficient than feeder roots. The fungi also protect the roots from drought, heavy metals and parasites. If the tree has mycorrhizal symbiosis it will be healthy and protected.

Decay

Decay fungi use various different methods to extract food from trees. Ganodermas tend to break down the lignin in wood, Laetiporus degrades the cellulose, whereas Ustulina attacks cell walls, causing a soft rot. It is important to understand the different characteristics of fungi in relation to trees. A tree should not be condemned just because a fungi is present- one should conduct a thorough survey. Look at the crown for healthy extension growth, look at the wounds for strong callusing, assess the biomechanics and use techniques avaliable to determine extent of hollowing. The tomograph is very good, but i believe one should check its accuracy using a core sample. Many people ridicule this, but the nylon hammer is a great tool for initial inspection. I am not sure that I can accurately map decay with the hammer, but one can instantly tell if further investigation is necessary.

Assessment

If decay is found to be present one will need to make a hazard potential assessment. What is the target value? Can this be reduced or removed. Can hawthorn scrub be planted at the base or the tree fenced off? If not, could one conduct a suitable reduction? I believe one should always try to keep the tree when possible. It may harbour rare fungi or endangered species. An assessment should be based on many factors- appearance of crown, extent of decay, fungal species, vigour- not just the presence of fruit bodies.

Identification

The first part of identification is to determine whether the fungi is annual or perrennial.

The flesh of a fungi is a very useful identification feature. Cut a small wedge in the fruit body and compare to books. Spore colours are also useful. Place a piece of paper- many fungi produce white spores so choose the colour carefully- and leave overnight to produce a spore print.

Please note: many of these fungi are rare and should not be collected...

Fungi

Mycorrhizal

Decay

Assessment

Identification

Fungi Gallery