wise use of mires and peatlands - Peatland Ecology Research Group

VALUES AND FUCTIONS OF MIRES AND PEATLANDS67Forestry type Industry term Forest management Wood resource /activities yieldNature None wood resource notconservationusedTransitory Exploitation Tree harvesting without continuous woodcollection adequate care taken of yield reducedforestryregenerationConserving Sustainable forest Tree harvesting with continuous woodmanagement management proper natural or yield maintainedforestryartificial regenerationProgressive Progressive Site amelioration continuous wood yieldmanagement management (drainage, fertilisation), increasedforestry forestry (afforestation),thinnings, ditch cleaningetc., final harvest, andregenerationTable 3/12 Intensity levels of mire utilisation for forestry 131 .In Fennoscandia nutrient-rich mire sites areusually dominated by Norway spruce (Piceaabies), although the proportion ofhardwoods, mainly pubescent birch (Betulapubescens), may be considerable. In nutrientpoormire sites Scots pine (Pinus sylvestris)predominates and in ombrotrophic sites it isthe only tree species. In the boreal zone ofNorth America black spruce (Picea mariana)is the predominant tree species on mires andoccurs alone or mixed with tamarack (Larixlaricina) or eastern white cedar (Thujaoccidentalis). In western parts of Canada,lodgepole pine (Pinus contorta) is also ofeconomic importance on mires 132 .Forest management on pristine mires:Forest management on pristine mires belongsto the categories of ‘transitory collectionforestry’ or at its best ‘conservingmanagement forestry’ (Table 3/12). Tomaintain a continuous yield the cuttingsshould be “light”, to prevent the site frombecoming wetter due to a rise in thegroundwater level. Pristine forested miresmay be one of the few cases wheremanagement to promote uneven-aged standstructure might be recommended (so-calledsingle-tree selection for continuous cover).Very little commercial tree harvesting is carriedout on pristine forested mires in Fennoscandiawhich are dominated by Norway spruce(Picea abies) or Scots pine (Pinus sylvestris),because single-tree harvesting is noteconomic 133 . A private landowner may,however, harvest trees from his wetlandproperty to be used for fuel or constructionon his own farm.In North America harvesting andregeneration of black spruce (Picea mariana)is significant, especially in Ontario andQuébec, Canada. It forms a major source offibre for the pulp and paper industry. A largeproportion of black spruce comes fromforested mires, in which it is important tominimise damage to the soil because of thelack of forest drainage. The preservation ofadvanced growth 134 , mainly black sprucelayerings 135 , is an essential feature ofregeneration of forested mires. On siteswithout sufficient advanced growth goodresults have been achieved with both seedtreegroups 136 and clearcut strips 137 .It is typical of the peatland forestry in Ontario