Orders for almost 100,000 trees have been cancelled by Northern Ireland buyers because of a post-Brexit ban on the plants being moved from Britain, the Guardian can reveal. Leaders in the business say it is a major setback for tree-planting programmes in Belfast and elsewhere in the region. The Woodland Trust in Northern Ireland has just cancelled an order for 22,000 trees, which were destined for schools and communities as part of a Northern Ireland greening project. “It’s a disaster. They’re just stopping any exports from mainland UK over to Northern Ireland. We can’t get any trees over from any of the nurseries that we would usually deal with over there,” said Gregor Fulton, an estate and outreach manager at the trust. Scotland-based Alba Trees, one of the biggest suppliers in Britain, selling around 250,000 trees a year to Northern Ireland, says it has also been hit. “At a stroke, Brexit has taken away a huge chunk of our business,” said Craig Turner, the chief executive. “We turned down an order of 70,000 oaks a couple of weeks ago because we can’t ship them.” And Belfast city council, which has an ambitious tree-planting programme involving 1m plants, confirmed it had a delivery of “300 large specimen trees” from a supplier in England “delayed due to new rules around the movement of plants” from Britain. The horticulture division that Brexit has created between Britain and Northern Ireland is expected to be raised at meeting between local business leaders and the European commission vice-president, Maroš Šefčovič, on Thursday. The issue is one of many problems caused by Brexit, including a ban on the export of live shellfish to the EU. “We thought it would be teething problems that would be resolved quickly. It just seems ludicrous really,” said Fulton. “The irony is that I can now get a tree easier from Latvia than I can from Britain, which totally undermines all the work on biosecurity,” he added, referring to the risk of importing pests and diseases. The problem arises from three new rules applying to Northern Ireland, which is observing EU customs and regulatory rules on plants and animals as part of the Northern Ireland protocol. A ban on British soil being moved into Northern Ireland emerged two weeks ago, with garden centres protesting about a block on supplies from British nurseries. Fulton said he had been told washing all the soil off roots could be the solution. “That’s just not practical. We got an order in last year of 56,000 trees in one go. You can’t wash 56,000 trees’ roots. It would be too big a cost and the nurseries are just not going to do that,” he said. If bare-rooted trees were available in sufficient quantities, buyers would then face Brexit paperwork involving health certification and customs for the plants. A further barrier stems from the EU’s list of species prohibited or restricted for import from third countries, which now includes the UK. The list is designed to protect Europe from diseases and pests, but includes native trees including oaks, alder and birch, important for mixed woodlands. Mike Harvey, director at Maelor Forest Nurseries in Wales, which sells about 32m trees a year, said it too had had to stop selling to Northern Ireland, with a recent order for 1,000 oaks about to be cancelled. What enrages Harvey is not so much the ban on movement of trees to Northern Ireland, but the continued importation of trees from Ireland for forestation projects. He said Brexit gave the UK an opportunity to close the border to EU trees and give the country a fighting chance of stopping the “drift of disease from south-east Europe to the north-west”. The diseases, which some put down to climate change, include ash dieback and the Xylella disease, which could enter the UK via olive trees and can affect several species of broad-leaved tree. “It’s typical that the EU puts these restrictions in place and applies them rigorously in Northern Ireland but we leave the borders open to trees coming in from the EU including Ireland and the Netherlands,” Harvey said. “If we want to control disease and give ourselves a chance, it’s actually a good thing to stop transportation of these trees between our islands.” The obstructions have emerged just as Northern Ireland’s environment minister, Gordon Lyons, launches a campaign to remind farmers they have only weeks left to apply for funding to plant native woodlands to help deliver on a pledge to plant 18m trees by 2030. A spokesperson for the Department for Environment, Food and Rural Affairs said it had “intensified work with the EU … to address the outstanding issues raised about the operation of the Northern Ireland protocol, such as those concerning the movements of plants, trees, soil and growing media”. It said the UK-EU joint committee to be held no later than 24 February would “provide the necessary political steer and approval to this work”. • This article was amended on 19 February 2021. Xylella disease could potentially enter the UK, but has not yet done so as an earlier version stated.