Scotland’s nature advisers have welcomed the move as a "significant contribution" in the fight to curb climate change.
Point and Sandwick Trust’s Beinn Ghrideag wind farm, built on common grazings land near Stornoway, is the largest community-owned scheme in the UK.
Its three turbines produce 9MW of green energy, enough to power 4,500 homes.
Over its 25-year operational lifespan it will also generate millions of pounds in community benefit for the local area.
The trust set up the Western Isles Croft Woodland Project in 2016, in partnership with the Woodland Trust.
Funded to the tune of around £70,000 a year, the scheme will see 100,000 trees planted over four years for a cost of £280,000.
Upwards of 100 schemes of varying size have already been planted across the islands, which historically have been virtually treeless, and there are several more in the pipeline.
More than 50 villages on Lewis, Harris, Barra, South Uist, Benbecula and North Uist have benefited.
Meanwhile, Westminster has set aside £10 million to see around 130,000 trees planted across towns and cities in England.
During a visit to the Lewis wind farm, David Maclennan, Argyll and the Outer Hebrides area manager for Scottish Natural Heritage, said: “It was inspiring to hear about the level of interest to date throughout the Outer Hebrides and the number of projects that have been supported, from the Butt to Barra.
"Small areas of woodland on good ground are exactly what we need to see in the Outer Hebrides – they will, over time, have a positive landscape impact, and by using largely native trees there will be benefits for biodiversity.
“With over 100,000 trees expected to be planted by 2020, that’s a significant contribution – and there is clearly potential to do a lot more.
“As well as the landscape and biodiversity benefits, these new trees will also help to absorb carbon from the atmosphere and contribute to our collective efforts to respond to the climate challenge. We’re now looking forward to further engagement with the Croft Woodland Project, and considering what role we can play in supporting the project going forwards.”
The award-winning wind farm is the brainchild of former local MP Calum MacDonald, who believes such schemes play an important in efforts to protect the environment.
He said: “This shows that community wind farms are in the vanguard of the fight against climate change. Not only has Beinn Ghrideag funded the planting of 100,000 trees and more through the Croft Woodland Western Isles Project but we also followed best practice in terms of peat restoration during the construction phase of the wind farm in order to minimise the peat disturbance and the amount of carbon it released.
“This method was so successful, in fact, that research by Lews Castle College at Beinn Ghrideag showed it had a carbon payback time of just 47 days – a drastic reduction on the previous estimate for wind farms of 2.3 years.”
Beinn Ghrideag has been operational since 2015 and currently produces £900,000 a year in net income for the local community.
Once capital costs have been repaid, it is expected to generate £2 million a year for support of projects in the Western Isles.