Conclusions

Following my research I have drawn some conclusions and proposals for additional research.

Tree assessment – The future of VTA?

Perhaps the future of VTA is technology reliant. A recent paper published by Meunpong, Buathong & Kaewgrajany (2019) compares VTA’s completed on google street view and in person in the field. The research demonstrated that table top surveys hold merit with existing practices. Key risks to utilities were identified along with tree species and trunk size.  However crown defects and size were not as clearly identified as the table shows below.

• 

 The research concludes, tree size estimation could become more accurate with practice and suggests that the development of advanced image capture software could improve accuracy even further.

I would propose that a development of software algorithms could take away the need to measure trees at all, perhaps all VTA will be desk based or an app could be developed to scan/video/photograph the external elements of the tree and then a risk report would be produced….this truly would result in a quantitative VTA !

Resistance Drilling:

As a user of the IML resistograph I would suggest that improvements to the training and guidance with the system could be provided. It has taken me a few years of use, practice and interpretation to feel confident of result interpretation. The system is delivered and an explanation of how to use it is provided but from a mechanical perspective only. A detailed handbook of examples of readings and the corresponding cross sectional photographs of drilled wood, would be of benefit to the inexperienced user. A database of such information on a website would be a wonderful resource that would support the standardisation of result interpretation. I personally drilled lots of different types of wood that had been felled in the yard. I photographed the results and have built up a collection that I can refer to if I am unsure, for example Horse chestnut decay I have discovered, can be difficult to interpret sometimes.

Trees as semi autonomous function units ?

To develop Lonsdales theory, research could be undertaken by copying the severing this tree suffered and observe defence and retrenchment strategies. Perhaps wounding in certain parts of the tree is less detrimental than others and maybe some tree species with higher levels of durable heartwood can take more wounding than younger trees with non-durable heartwood?

PDA proscriptions as part of VTA recommendations..

The question remains…..why are we not prescribing PDA application to health Horsechestnuts as part of tree management programmes? …maybe because we are programmed to focus on immediate risk… cost benefit analysis research may support this argument.

Decay progression…thoughts

Decay stage and dynamics need to be better considered as part of risk assessments to reduce the number of unnecessary fells that deprive society of aging and interesting tree stock. Ideally a non-wounding decay detection device that could scan a large section of the horizontal decay patterns of stems would provide the information needed to reduce the probabilities of incorrect prognosis made by tree inspectors.

 If in time, a scanning system is produced it will still require a skilled operative to interpret results and provide prognoses with reference to risk. I would like to think that with more knowledge, comes the understanding and acceptance that a fruiting body does not always equal a risk that is unacceptable to the general populous. I hope that the next generation are taught to carefully risk assess and as part of VTA prognosis a cost benefit analysis of the tree is completed. Perhaps this way, we will have more interesting aged and veteran trees in situ to enjoy, observe and learn from.

WORD COUNT 4040

M TROMANS 9548