Also known as Atlantic or temperate rainforest, the habitat is home to many globally scarce plants - including some unique to Scotland.
The woodlands grow in the ‘hyper-oceanic’ zone on Scotland’s west coast, with most of the remaining forests found in Argyll.
They are just as significant and even less common than their better-known tropical counterparts.
The announcement comes as world leaders from 100 countries sign up to the Glasgow Declaration at COP26, pledging to end deforestation by 2030 and protect the planet's “lungs”.
Scotland is home to its own Atlantic rainforest boasting a variety of rare species and habitats,” said Scottish environment minister Mairi McAllan.
“We want to protect and expand this precious environment and we have committed to do so in the life of this Parliament.
“I welcome the Glasgow Declaration’s strategic vision, which recognises that forests and woodlands have a crucial role in reversing the effects of climate change and nature loss.
“As an active global citizen, Scotland is playing its role with world-leading ambitions in reaching net zero by 2045, five years before the rest of the UK.
“Our forests and woodlands are an important net carbon sink, absorbing around 6.2 million tonnes of CO2 [carbon dioxide] every year – equivalent to almost 10 per cent of Scotland’s gross greenhouse gas emissions.”
Scotland’s rainforests thrive on cool summers, mild winters, wet conditions and clean air – ideal conditions for some of the world’s rarest mosses, liverworts, lichens, fungi and ferns.
Argyll is home to more than half of all the remaining habitat, which totals around 30,000 hectares.
Restoration work will be centred around this area.
The Scottish Government is working with the Alliance for Scotland’s Rainforests, comprising a diverse group of organisations and public sector bodies, to determine how best to fulfil these commitments.
Other actions to be supported in a bid to boost Scotland’s natural economy include expanding the nature restoration fund, supporting creation of a new national park and local nature networks, protecting and restoring Atlantic rainforest and ancient woodlands, and investing more in peatland restoration and expansion of woodlands.
Four out of very five trees planted across the UK are in Scotland, which has upped its national planting target from 12,000 hectares a year to 18,000 a year – around 36 million new trees – by 2025.
It’s thought the 2021 target, for 13,500 hectares, is within reach.
A shortfall in 2020 was partly blamed on the Covid-19 pandemic.
The Glasgow Declaration on Forests and Land Use is the COP26 climate summit's first major deal.
UK Prime Minister Boris Johnson said: “Time is running out to protect our tropical forests from irreversible loss.
“Communities, livelihoods and endangered species rely on these vast ecosystems.
“History will not judge us kindly if some of the world’s most precious resources are degraded on our watch, given their crucial role in helping us limit the rise in global temperature.”