12 - Afforested and forestry-drained peatland restoration

Summary

Introduction

Restoration of afforested peatlands was initially driven by recognition of the high biodiversity value and increasing scarcity of peatlands in their natural state. Now we recognise that peatlands also play an important role in climate regulation, raising the question: should we be restoring afforested peatlands on a large scale as a climate change mitigation measure? This needs careful consideration because it involves sacrificing the initial investment in afforestation and taking land out of economic production. And what if we realise when it's too late that the peatland forests were benefiting us in previously unrecognised ways? We need to consider all the goods and services that afforested peatlands provide and weigh these up against those they will supply if we restore them. This chapter provides the background to the restoration of afforested peatlands, looks at the scientific evidence on how afforestation and restoration affect ecosystem services, summarises lessons learned from practical projects and attempts to answer the question: should we be doing more of this in future?

The chapter focuses on temperate and boreal peatlands. Tropical peatlands are dealt with in Chapter 14 of this book. This chapter deals with the restoration of naturally forested peatlands that have had the growth of their natural tree cover boosted by forest drainage (forestry-drained peatlands) and naturally treeless peatlands that have been afforested by planting (afforested peatlands). Much of it also applies to peatlands that have become forested naturally as a result of drainage or peat cutting (sometimes also termed ‘afforested’).

There are two main contexts reflecting differing degrees of natural tree cover on mires and different peatland forestry practices. In the northern coniferous forest or boreal zone, some mire types have a natural cover of slow-growing trees. During the twentieth century, in Finland, Sweden, Norway, the Baltic countries, Russia, and to a lesser extent in Canada and the United States, forest drainage was undertaken on these wooded peatlands to stimulate growth of the existing tree cover and thus form productive forest stands. Drainage for forestry has been the most extensive use of boreal peatlands, affecting more than 15 million hectares, 90% of which is in Scandinavia or Russia (Paavilainen and Päivänen 1995).