Kew's head of arboretum Tony Kirkham, Trees in Towns II author Mark Johnston and well-known consultants David Lonsdale and Jeremy Barrell will headline the seminars.

Colin Bashford, praised at a recent 40th anniversary do at Surrey's Merrist Wood, tree contractor Andrew Cowan and Glyn Percival of Bartlett Tree Experts will also speak.

The seminars, to be held early next year, follow a successful series of talks at Barcham Trees in Ely, Cambridgeshire, earlier this.

"Seminars are free and speakers give their time as a way of disseminating information," said Barcham sales director Keith Sacre.

"The events are a conduit of information. We do a lot of work with tree officers and it's good to give something back."

Sacre added: "We were delighted by the response to our 2008 seminars, all of which were heavily oversubscribed.

"So we have decided to increase our programme for 2009. They days present an opportunity for tree officers and other arboricultural professionals to network."

Attendance is limited to 40 people and will be allocated on a first-come-first-served basis. Contact keith@barchamtrees.co.uk.