The Scottish peatlands have become an unlikely provocateur of one of environmentalism’s main questions of late: is tree-planting always a good thing?

Scotland’s Flow Country, a 400,000-hectare expanse of peatlands, mountains and straths (wide river valleys) that straddles the country’s northernmost two counties Caithness and Sutherland, is now a prized landscape and proposed World Heritage site, both for its beauty and the benefits it provides (more on those later).

Ground-nesting birds such as curlews (Numenius arquata), greenshanks (Tringa nebularia) and dunlins (Calidris alpine), and mammals like red deer (Cervus elaphus) and otters (Lutra lutra), live in its soft lands and dark waters, colored by the decaying debris known as peat. The lumpy, waterlogged ground is peppered with sedges and lined with vivid-green sphagnum moss.