A look at Scottish forestry and the issues currently facing it shows that the Scots are dealing with much the same problems as our own forest managers. The spread of invasive species is a familiar matter in Latvia too. Invasive alien species are one of the main direct causes of biodiversity loss worldwide. The Scots are putting considerable effort into controlling and containing invasive species on Scotland's national forests and land as well.

The invasive plant species being controlled in Scotland are Pontic rhododendron (Rhododendron ponticum), gaultheria (Gaultheria shallon) and American skunk-cabbage (Lysichiton americanus).

Support is also given to work by organisations and local authorities to control unwanted animal species and their spread — for example North American signal crayfish, American mink (which do serious damage to local duck populations) and grey squirrels (Sciurus carolinensis), which threaten the survival of the United Kingdom's native red squirrel (Sciurus vulgaris).

Pontic rhododendron (Rhododendron ponticum)

Probably the best-known alien invasive plant in Scotland is Pontic rhododendron (Rhododendron ponticum, referred to below simply as rhododendron), which reduces biodiversity and soil quality. As is well known, in Latvia the rhododendron is a delight to garden owners and a fairly popular ornamental, whereas the Scots are fighting this “foreign friend” by every means available.

Rhododendron is very hard to get rid of and harmful to many other species. Research shows that rhododendron reduces the number of earthworms in the soil, for instance. It physically crowds out the native flora and also hampers the natural regeneration of woodland.

Scotland's foresters have been working to halt the spread of this plant for more than 25 years, and it still “smothers” a large part of Scotland's west coast and threatens the unique habitats of the temperate wet woodlands known as Scotland's rainforest.

Foresters' fight against rhododendron

Technology

The organisation uses drones to help map the areas where rhododendron control work should be concentrated. This gives Scotland's wet woodlands (referred to below as Scotland's rainforest) a chance to “draw breath”.

Restoring Scotland's rainforest

In the course of rainforest restoration work, Forestry and Land Scotland specialists identify areas where rhododendron is affecting habitat quality. The situation is then brought under control through the careful use of certified herbicides approved for this purpose. New, more effective stem-injection methods have cut the time needed to treat an area by roughly 50%. Because the treatment is highly successful (90-100%), the need for repeat treatment is greatly reduced.

Digging out young plants

Active work is under way to improve the surveying of remote areas and to identify so-called rhododendron pioneer bushes before they establish themselves and become harder to tackle.

Promoting a “landscape-scale” approach

“Landscape-scale” coordination is carried out to a very high standard. In the Glen Creran area, for example, rhododendron has been eradicated thanks to a four-year community project led by the Argyll and the Isles Coast and Countryside Trust. Work of this kind naturally demands considerable effort, along with the goodwill and support of local residents.

Earlier this year Forestry and Land Scotland received £1.3 million in Scottish Government funding to step up efforts to save Scotland's rainforest. The funding will not only intensify work to eradicate invasive rhododendron and to control deer populations, but will also help the organisation develop a long-term strategy to protect this unique habitat — Scotland's rainforest, a third of which is managed by Forestry and Land Scotland.

*Gaultheria (Gaultheria shallon)

Gaultheria is an evergreen member of the heather family brought over from North America, cultivated in the 19th century and planted to provide habitat for game animals such as roe deer.

In recent years it has become highly invasive, particularly in Argyll and the west of Scotland, in places where rhododendron once grew. Unfortunately, once gaultheria has been cleared it regrows very rapidly.

**American skunk-cabbage

American skunk-cabbage is planted as an ornamental aquatic and is most often found at pond edges, along stream banks, in bogs and in wet woodland.

Tall, with large, leathery leaves and bright yellow “flowers” resembling those of native plants (the so-called lords-and-ladies), it has gradually spread from gardens into the wild and become a serious problem throughout the United Kingdom.

As with rhododendron, gaultheria and American skunk-cabbage are controlled using certified herbicides approved for such use, which pose no threat to other plant species or to animals.

***Grey squirrels

Foresters help control the grey squirrel population by installing artificial den boxes for pine martens in the woods, in order to increase marten numbers in particularly problematic areas. Pine martens hunt grey squirrels, but manage to coexist successfully with the more agile native red squirrels.

On the subject of controlling alien and invasive species, senior Forestry and Land Scotland specialists stress that biodiversity in Scotland is threatened by many alien species, and that these are also highly undesirable in Scotland's unique and most valuable rainforest.

Invasive plant and animal species are very difficult to eradicate. Achieving lasting success requires a coordinated approach, working together with like-minded and responsible land managers, and often at what is termed the landscape scale.

Forest and land owners in Scotland can take part in voluntary schemes that support the control of invasive plants and animals.

****Fife council landowners and private garden owners are being urged to help control the grey squirrel population by using traps. This can also halt the northward spread of squirrelpox (a disease carried by grey squirrels that kills red squirrels). The appeal was made in early May 2024, when a red squirrel that had died of squirrelpox was found in the north of Dunfermline.

Gardeners can help protect Scotland's natural environment by choosing sensibly what to plant and by checking what is already growing in the garden. Although alien plants have enriched the United Kingdom's gardens, a small proportion of them have become highly invasive, threatening native habitats and native species. The Royal Horticultural Society regularly publishes a list of invasive alien plants along with advice on how to control or remove them properly.

* Gaultheria shallon, or gaultheria, is an evergreen shrub of the heather family (Ericaceae), native to western North America. In English it is known as salal, shallon or (mainly in Britain) gaultheria. It branches very densely and in the wild often forms almost impenetrable thickets. The shrub's leaves are variable, evergreen, leathery and thick, with an egg-shaped form. The upper surface of the leaf is glossy and dark green, while the underside is rough and paler. The leaves are 5-10 cm long.

** American skunk-cabbage (Lysichiton americanus Hultén) is a North American species with large leathery leaves and pale yellow flowers. It is a plant up to 1.5 m tall that favours bogs, wet woodland and the banks of rivers, lakes and ponds. American skunk-cabbage produces one or two (sometimes as many as four) ornamental flower spikes up to 45 cm long. This attractive-looking plant was introduced to Europe about 100 years ago as an ornamental. Skunk-cabbage grows and spreads rapidly, and within just a few years its large leaves form a dense cover that completely blocks sunlight from reaching the ground beneath them. Today it has spread into the wild in nine European countries, the nearest to Latvia being Denmark, Germany and Finland.

*** The grey squirrel (Sciurus carolinensis) is a rodent of the squirrel family (Sciuridae), in the tree squirrel tribe (Sciurini). It is native to North America, where it can be found on the eastern seaboard of the USA, in the central part of the west coast and in southern Canada. The grey squirrel has also been introduced to Europe — to Britain and Ireland. Because the grey squirrel is larger than the red squirrel (Sciurus vulgaris), it has driven the smaller native squirrel out of the woods. There are districts in which red squirrels have given way to greys entirely. Scientists are concerned that the same replacement could happen in Italy. The grey squirrel is also found in small numbers in southern Africa. In the scientific name Sciurus carolinensis, the genus name Sciurus comes from two Greek words: “skia” meaning “shadow” and “oura” meaning “tail”, together conveying the idea that the squirrel is an animal that sits in the shadow of its own tail. The species name carolinensis refers to the Carolinas in the USA, where the grey squirrel was first studied scientifically and where it remains widespread.

**** Fife (Fife) is the third largest local authority area in Scotland by population. It has around 370,000 inhabitants, more than a third of whom live in its three largest towns, Danfermline, Kirkcaldy and Glenrothes. On the north-east coast of Fife lies the historic town of St Andrews, home to the University of St Andrews, the oldest university in Scotland and one of the oldest in the world. Fife has been an important royal and political centre of Scotland since the reign of King Malcolm III in the 11th century.