As the government also warned Canberrans against the illegal collection of firewood, they reported 400 young trees on public land had been vandalised or stolen this financial year.

The figure was already greater than the numbers in each of the past three years and a sharp rise from the 230 similar incidents in 2013-14.

An ACT government spokeswoman said the increase in young trees damaged was proportional to an increase in tree planting, with more than 10,600 trees planted in 2013-14, up 44 per cent from the year before, and 10,200 so far this financial year.

The top suburbs where young trees were found vandalised or to have been removed this financial year were Forde, Macgregor, Dunlop, Franklin and Harrison, which the spokeswoman said was reflective of where trees had been recently planted.

Records were not kept of damage to established trees but one recent incident involved the felling of pine and eucalyptus trees at Fadden Pines and Pine Island.

"There are major concerns with this kind of vandalism as an unskilled person damaging a tree could injure themselves or cause damage to the tree which has the potential to injure others at a later time," she said.

Rural leaseholders can fell trees on their own land if they are non-natives or if they have been planted by them. The cutting of native trees requires government approval, she said.

"Residents in suburban and rural properties in the ACT may collect fallen timber for personal use as firewood if it is from their own property."

There are 24 authorised firewood merchants in the ACT, with a rural leaseholder requiring Environment Protection Agency authorisation before they are able to sell to one of these merchants.

Grazier Brett McDonald, from Williamsdale, said he used some of his timber for his wood heater.

"We clean up old dead wood, we don't touch the real old trees, because I'm a bit of an old greenie too, as a farmer, but the nice firewood we clean up," he said.

"We also do it for our own fire protection."

Mr McDonald said he may this winter use some of the wood left from the government's felling of native yellow boxes as part of the construction of a pipeline through his property.

Laws require merchants to supply only seasoned firewood, containing not more than 20 per cent moisture, and to tell customers of the timber's name and where it was originally taken from.

The maximum penalty for cutting native trees or removing native timber from public land is $7500 for an individual and $37,500 for a business.