As the Yorkshire Dales and Lake District are extended, the CLA is calling for farmers to be given the flexibility to stay profitable.
CLA North director Dorothy Fairburn advised farmers to work with the park authorities, but added there were risks.
“The new designation will mean planning rules are more stringent,” she said. “Designation should be a catalyst for innovation, not a barrier for development.”
The CLA is concerned about the grey area farmers who applied for planning permission before the extension on 1 August now find themselves in. CLA Lancashire chair John Welbank, a rural regeneration consultant, said the local authority had already changed the way it made decisions.
“During the last couple of months the local authority has been nervous about new permissions,” he said. “We’ve got a couple on appeal at the moment that would normally have been approved.”
Council planners had been hindered by late release of guidance on interim policy, issued just two weeks before the extension. “In theory it’s clear,” he said. “Applications submitted before 1 August are subject to local authority policy.”
Now the boundaries have changed, farmers in the extension areas have lost certain permitted development rights. Mr Welbank explained: “They can’t just stick up a building. They can’t turn barns into residential properties.
"A converted barn can be worth £750,000, which you can reinvest in the farm. Now that barn is worthless.
“Small tasks like fixing a slate roof become complicated and expensive. The park authority can specify what kind of slate and even where it’s from.
“New builds, conversions, extensions and diversification will all become harder. There’s still support for diversification, but it’s subject to lots of conditions.”
Mr Welbank’s farm and caravan park, Ireby Green Farm in Cowan Bridge, borders the new boundary.
“I’m glad we’re outside,” he said, adding that he believes the extension will not bring farmers the extra investment or tourism promised: “There’s no threat to the area, so why do it?” he said.
Yorkshire Dales National Park Authority chief executive David Butterworth said: “Extending the boundaries should provide a boost to rural tourism in the area, supporting rural businesses and potentially adding millions more to the £4bn already generated by visitors to the national parks each year.
“We’ll be listening to and learning from the local communities, farmers, landowners, interest groups and businesses to enable us to develop productive, long-term relationships with all these parties.
"I genuinely believe that by working together we can make the most of the wonderful opportunities for the landscape, local communities and the economy.”