Traditionally most hill farmers have been opposed to large-scale planting of trees arguing that it threatened fragile, rural communities by removing those families involved in sheep farming.

Nothing stays the same forever, and the chill winds of economic reality have seen hill sheep numbers halved in many areas of Scotland.

Those who own land in our hills and uplands aren't stupid. They have done their sums and some have opted to remove sheep from their land in favour of more lucrative deer stalking and grouse shooting. With Brexit looming, and the real possibility of lamb prices collapsing combined with a seismic shift in the way hill sheep farming is supported, many are now seriously considering planting their marginal hill land with trees.

The UK is the fourth largest net importer of timber/timber products. The weaker pound as a result of the Brexit vote has boosted timber prices. Demand for logs is strong and biomass markets have lifted the value of small round-wood.

On top of improving prices, there is also considerable cross-party political support in Holyrood for forestry expansion that has led to attractive grants being made available. For example, support from the Scottish Forestry Grant Scheme, approximately £4,320 per hectare, is likely to run to a surplus - it costs approximately £3,000 to £3,500 to establish a crop of trees.

The arguments for planting marginal land with trees in favour of grazing it with sheep were well-documented in an independent study commissioned by Confor, the body representing the forestry industry, in 2013 and updated in 2014. It made a specific economic comparison between an established productive conifer forest at Eskdalemuir extending to 20,000 hectares and agriculture on an equivalent area of land.

The study indicated that once in a sustainable productive cycle, forestry generates around three times the economic output of hill sheep farming before subsidy payments. Farming required a public subsidy of £22,600 per FTE (full time employee) to survive, while forestry received a modest contribution of one sixth that of farming.

Once established forestry is also much less dependent on annual subsidy payments to maintain viability. Forestry generates a significant trading surplus before subsidy, while hill farming trades at a loss.

Forestry also resulted in almost double the level of spending in the local economy as agriculture.

The results detailed related only to Eskdalemuir and were not directly comparable with farming or forestry in other hill areas of Scotland due to wide variations in productivity, costs, returns, subsidy eligibility and subsidy rates. Nevertheless, many landowners have come to the same conclusions as the report and are looking very seriously at forestry as an option in the light of Brexit uncertainties.

Patrick Porteous, a partner in forestry and woodland specialist John Clegg & Co reckons it is important to establish woodland with sufficient scale to make it economically viable and said: "In the past, many shelterbelts have been planted around farms, which has helped with diversification and in providing shelter for livestock. But once those shelterbelts mature they are not necessarily economically viable for harvesting, given such problems like extraction across fields. So it is important to get the design right and infrastructure in place for access."

Mr Porteous says he rarely sees large parcels of land for planting coming to the market, simply because they are sold very quietly off-market between a farmer and a forestry company. He knows of two major forestry companies that are accumulating land for planting through this method for clients.

"It could be that farmers are getting good value. After all, it is a transaction between a willing buyer and a willing seller. However, most properties are sold on the open market for good reason. It guarantees that the seller is achieving the best possible price in the open market at that time. Whereas, through negotiation (off market) you are never really certain what that best price is if you are only negotiating with one or two buyers."

Mr Porteous said there is a significant amount of capital looking to be invested by private investors, who rightly see a future in the production of timber.

He went on to suggest that farmers could consider applying for planting approval and then market their land. "It would allow the seller to realise full market value in the land, reduce the risk for the buyer and ultimately our government would achieve the planting target of 15,000 hectares per year going forward. It would certainly stimulate more business in the rural economy which is in danger of stagnating."