Managing trees in the urban environment
The Northern Branch was delighted to host its spring seminar – ‘Managing trees in the urban environment’ – in the spectacular surroundings of Croxteth Country Park, Liverpool.
I introduced the seminar with a presentation emphasising the benefits that urban trees provide, to set the scene for the day.
First up was Howard Gray of GreenBlue Urban (GBU) who delivered an excellent presentation entitled ‘Unlocking the Green Potential of Trees in Urban Space’. He went through the GBU processes of tree planting and successful tree establishment in urban areas. He demonstrated how proper tree pit design could contribute enormously to sustainable urban drainage (SUDS) using case examples. Howard described some really interesting case histories from Blackheath in Greenwich to St Peter’s Square in Manchester, amongst many others, and described in detail a scheme at Leyland Street in Prescot, which is only a few miles from Croxteth Hall.
Howard’s passion and enthusiasm for his work and for trees are boundless and infectious.
Howard was followed by Keith Sacre of Barcham Trees and the Association’s current Chair. Keith started with biosecurity and used the London i-Tree Eco study to demonstrate the cost to London if plane wilt disease, Asian longhorn beetle and emerald ash borer were to be introduced. Keith spelled out in detail the implications for all our plants, not just trees, if Xylella fastidiosa were to arrive in Britain. He emphasised the need for us all to be on guard and alert to the threats, and he praised the Association for taking the industry lead on biosecurity. He had special praise for Defra and in particular Professor Nicola Spence and her team for what they have achieved.
Keith described how a section on biosecurity in the draft of BS8545 would have required that all imported trees would have to be kept on the nursery for a full 12 months’ quarantine, before they could be released into the landscape and certified as pest and disease free. However, this had to be omitted because of an objection from Europe that considered it to be a barrier to free trade. Happily, Barcham Trees has adopted it as it’s Biosecurity Policy.
After a splendid lunch, we were treated to an excellent presentation on ‘Tree Planting and Soil Amendments’ from Dr Glynn Percival of the Bartlett Tree Research Laboratory at Reading University.
Glynn went through the problems of pot-bound rooting systems and how to deal with them in order to obtain successful establishment, using results of research undertaken at the Bartlett Lab. He described the benefits of soil decompaction using compressed air to enhance vitality. Glynn described the results of research on the use of ‘pure’ mulch, i.e. woodchip mulch from a single species of tree.
It seems as if pure mulch of wild cherry (Prunus avium) and hawthorn (Crataegus monogyna) produced the best results. The mechanism is not fully understood but mulching does result in significant increases in fine root production. It is possible that some of the chemical compounds these mulches release into the root zones act as systemic inducers of resistance (SIRs) which can enhance a tree’s natural resistance to pests and diseases.
Glynn then turned his attention to the use of biochar as a soil amendment. Finally, Glynn described how Bartlett brought a signature tree in Texas, the ‘Lone Star Pecan’, back from the brink of death. The techniques were simple and were those he described during his presentation, i.e. soil decompaction, mulching and soil amendments, none of which are expensive.
As Chair for the day and on behalf of the Northern Branch, I thank all three speakers for giving us an excellent day’s CPD. The programme was excellent and attracted delegates from as far north as Glasgow and Newcastle upon Tyne. In my opinion, the venue was second to none, but I would say that, wouldn’t I?