SCOTLAND’S rainforests may be less widespread than their tropical namesakes but are just as threatened due to foreign invaders.

But now a multi-million pound scheme has been launched to save the country’s under threat temperate rain forests from invasive species such as rhododendron.

Conservationists have started a widespread plan to kill the rhododendron bushes from the unique ancient Celtic rainforests along the west coast as they become increasingly choked with the plant which is causing the climate to change on the forest floor.

The west coast has some of Europe’s best examples of epiphyte communities, which is the collective term for lichens, mosses and other plants which grow on trees to avoid competition for sunlight on the forest floor.

Rainforests are found along the west coast where the moisture-laden Gulf Stream from the Atlantic Ocean comes into contact with the land and condenses into rain.

The woodlands are classed as cool-temperate rainforest, which is also found on the coasts of North America, Norway, Japan and New Zealand.

It is the sheer quantity of rain, coupled with a mean annual temperature that is neither too hot nor too cold, that enables temperate rainforests to thrive in Scotland and in other isolated pockets around the world.

But the rainforests have become fragmented with around 50 per cent having been destroyed already and the habitats have become even more endangered than their more famous tropical counterparts.

Now Scottish Natural Heritage has launched an action plan with other conservation charities which will see the invasive species have their roots killed so they die slowly.

If the forest floors are cleared too quickly, the temperature and moisture levels can change and kill the rare and sometimes unique epiphyte communities that live there.

Plans have been drawn up that will see conservationists attempt to clear vast areas of the remaining strongholds in Argyll in a bid to keep the unique habitats thriving for centuries to come.

Davie Black of conservation group Plantlife Scotland said: “Rhododendron bushes were introduced in the 19th century and while they look great for one month of the year they are killing the rainforests.

“Our Celtic forests are home to some of the rarest species on the planet and it is vitally important that we preserve them and do it properly so they will thrive.

“If we clear them too quickly then the light and temperature changes which can be disastrous for some species. As well as being beautiful, the woodlands are extremely important in ecological terms too.

“Scotland provides probably the best examples of these epiphyte communities in Europe, owing to the long ecological continuity of forest remnants, and low levels of air pollution.”

Scotland’s rainforests are relics of once great swathes of forest strung out along the Atlantic coastline dating to the last ice age, about 10,000 years ago.

The woodlands are also invaluable for protecting against flooding as they act like sponges and soak up the heavy rain, but clear felling in the 18th and 19th centuries left them fragmented along the coast.

Many European temperate rainforests have already become degraded as a result of pollution or poor management but Scotland represents some of the best examples of the habitat anywhere in the world.

Lichens are vital to the ecology of Scotland as they are able to fix atmospheric nitrogen which very few other species can do.

They are also primary producers of biomass and play an important role in soil formation and also provide a habitat to a whole array of creatures.

Many of the plants, such as the ferns with translucent fronds one cell thick that can only survive in constant humidity, are extremely rare.

Because the Atlantic air is clean it nurtures extraordinary lichens with names to match their bizarre looks – smokey Joe, octopus suckers, black-eyed Susan, blackberries in custard.