Coillte plans to harvest 40 acres of coniferous trees on Inchagoill Island, an important archaeological site on Lough Corrib, and replace them with oak, ash and sycamore, as well as Scots pine.
The island is one of the biggest on the lake, and commands a strategic position about midway between Oughterard and Cong. It is thought to have been first settled by nomadic hunter-gatherers about 7,000 years ago, who would have found a good living in the bountiful waters of the lake and along its shores.
Monks founded a monastery on the island in the early Christian era, while a later colonisation is reflected in the island's name, Inis an Ghaill, the Island of the Foreigner.
The archaeological remains visible on the island include a graveyard, two churches linked by an ancient road, two cross-inscribed pillars and a holy well about 250 yards from the main complex.
Its most famous monument is an inscribed pillar headstone which marks the grave of Lugnaed, son of Mernuch, believed to be St Patrick's sister. This slab is thought to be the oldest inscribed Christian stone in Europe, outside the Roman catacombs.
It is likely, from studies on other lake island monasteries such as Inis Cealtra on Lough Derg, that a wider range of remains such as field systems, house sites, kilns, weirs and possibly other church sites lie buried in the trees.
On the other hand, any such remains may have been considerably degraded when the island was planted with its existing crop of Douglas fir, sitka and Norway spruce following Hurricane Debbie in 1961.
Coillte describes the plan to replace the conifers mainly with broadleaf trees as "an environmental rather than a commercial project". It says the work will be carried out "in an environmentally sensitive way" which will not interfere with the monastic remains.
The State forestry company has consulted widely with other State bodies such as the OPW, and local interests such as An Taisce and the Lough Corrib Anglers' Federation, and claims broad support for the project.
An Taisce and the anglers are now largely satisfied by Coillte's assurances, although An Taisce would ultimately prefer ownership of the island to be transferred to the National Parks and Wildlife Service.
The anglers' federation represents about 2,000 members in 16 clubs. Its secretary, Mr Brendan Madden, says they will be keeping "a very close eye" on the felling.
According to Coillte, the trees will be ferried rather than floated to Cong, in order to minimise disruption to lake users.
"Felling or extraction will not take place near monuments or archaeological sites, so access to these areas will remain open," the company said in a statement.
Coillte's regional manager in Galway, Mr Vivian Ryan, said that even though the replacement of the conifers with broad leaves will be costly and time-consuming, "the opportunity that it presents to enhance the island is welcome".
"Inchagoill has tremendous potential as a public amenity and it is Coillte's firm intention to retain ownership of the island and to ensure that it is available to future generations of local people, tourists, archaeologists and anglers," he said.
The trees will be harvested using two machines, a forager and a processor, and then shipped to the mainland on barges. The work is due to start by the end of the month and about 7,000 tonnes of timber is expected to be harvested over the following three months.
The work is being carried out at this time of year in order to minimise disruption to angling interests by avoiding the mayfly season. The company hopes to complete the work relatively quickly.
"We have such a limited window that we need to do it in as compact a time-frame as possible," Mr Ryan said.
Some concern has been expressed locally that using machines rather than chain-saws to harvest the trees may increase the risk of damage to the island. The opposite is the case, according to Mr Ryan, as the machines hold the trees upright rather than let them fall uncontrolled on the ground.
Replanting the island with broadleaf trees will enhance its character, while the inclusion of Scots pine will continue a link with a Scots pine wood planted in the last century.
"It will look like we have the builders in for about two years. But after that it will regenerate itself very quickly," Mr Ryan said.