The disease is threatening Britain’s 80 million ash trees after first being spotted in February 2012. In 2009, the HTA warned Defra that chalara was an issue on the continent and was likely to be imported into the UK soon.
HTA business development director Tim Briercliffe said the importation was not "sensible". He added: "The Forestry Commission was aware of the problem in 2009 but carried on specifying. The Forestry Commission has not been sensible in what they have been doing, to be honest. I don’t know if there is a disconnect between their research arm and their procurement side but there’s definitely been a breakdown in communications.
"We told them in 2009 about the risk but they continued to plant ash trees. It doesn’t matter if it was direct or via a third party, the result is they imported them into the country and planted them on their sites. They could say some of the disease is caused by wind-blown spores from abroad but even if you accept that it would only be in East Anglia and Kent and not the rest of the country and they have infected sites in Scotland which can only have been brought in from other countries and planted there."
A Forestry Commission representative said: "In the five years since 2007, the Forestry Commission in England, Scotland and Wales has been supplied with 1.642 million ash plants by our own nurseries and commercial suppliers. Of this total, 70,400 (4.2 per cent) had been imported by a commercial supplier. All the imported plants were supplied in the 2010-11 planting year.
"We use our contractual arrangements with suppliers to avoid receiving diseased material, and to return any plants which do not meet contract specifications. Before 2012 we had not been aware that there was a problem with Chalara infection in the UK ash trade or in imported plants.
"EU procurement rules were followed when we tendered our plant supply for restocking purposes in 2009 and, while we were advised that we could specify that the stock should be from certain UK seed provenances and be disease-free, we were also advised that we could not limit our tender invitation to UK suppliers.
"A framework contract for the supply of ash plants for restocking to the Forestry Commission was instigated by our Plant & Seed Supply Branch. This was subsequently awarded to certain UK growers, one of whom, we now know, obtained part of our requirement from another UK nursery, which sourced the material from a nursery outside the UK.
"The Forestry Commission follows internal guidance on handling plants for successful planting. Provided in the guidance is a suite of checklists for supervisors to use to check and record any problems with plants on delivery to a planting site. Checks are also made and reported after planting and at the time that a plantation is considered to be established."
More than 5 million ash plants have been imported to the UK for forest and landscape planting since 2003, according to Defra.
The disease has now spread to 309 sites since first being found in the UK in February - 17 nurseries, 132 recently planted sites and 160 established woodlands. There are 22 sites managed by the Forestry Commission in Britain that have, or have had, Chalara fraxinea infection. There are 1,028,000 hectares of land in Forestry Commission management.