Forestry premiums for farmers are being reduced or withheld as a result of the Department of Agriculture's revised mapping methods, the IFA has claimed.
The association's forestry chair Vincent Nally said the Department must honour afforestation contracts if planting rates are to recover.
The level of farmers' forestry planting has decreased from 6,009 hectares in 2013 to 3,242 hectares in 2017.
"The re-digitisation of forest area as part of control checks continue to result in farmers' payments being reduced despite the IFORIS system - the online computerised mapping and payment system - being in operation for over 12 years," said Mr Nally.
All afforestation applications are made online by the registered forester on behalf of farmers, but mapping issues result in farmers' forest areas being reduced at Form 3 stage or later on in the premium term.
"This is undermining confidence in the afforestation programme and has caused farmers to distrust the scheme as in some instances their premium payment has been reduced on more than one occasion," said Mr. Nally.
He added that there are other issues with the scheme that are negatively affecting the perception of forestry and are directly related to the significant decline in farmer planting under the current programme.
"There are farmers that have had their forest area re-categorised or totally excluded from premium payment, even though their application was approved by the Department at establishment stage. This has resulted in their premium payment being reduced with significant financial implications for them," the IFA representative said.