Coppice (Niederwald): In the Middle Ages, such forests were used to obtain oak bark for tanning and firewood (see Fig. 4.1.12 D). The whole forest was used in 30-year cycles and regenerated from the coppiced trees (coppicing). Thus species that could regenerate were selected for (e.g. hazel, oak, hornbeam). Today, in many developing countries, afforestation (e.g. with Eucalyptus species) is used as coppiced forest.
Mittelwald: A form of management in the Middle Ages (Fig. 4.1.12 C) in combination with agriculture. Few tree individuals (mainly oak) were grown to supply timber for construction and more tree individuals being used as coppice for firewood in a 30-year cycle. Valuable oak for veneers comes today often from these forests (still widely distributed in France). Earlier in these forests births and marriages were celebrated by planting 510 year old trees grown from seed. Thus an open canopy of unequally aged canopy trees was maintained and a sustainable supply of timber for use in construction was ensured.
Hochwald: This consists of trees which had grown from seed (in contrast to regrowth from coppiced trees in low forest; Fig. 4.1.12B). The stand of trees was completely managed. Use was by (1) clear felling: All trees on an area were felled at the same time, (2) partial felling (umbrella felling): Some of the trees remained, as protection and for seed production, distributed uniformly over the area. Regeneration then occurred "under an umbrella". The use of the protective trees then proceeded either after successful regeneration (beech) or after twice the normal cycle of use (pine, oak). Thus some of the trees were twice as old as the average age of the stand. For oak, which becomes most valuable after more than 300 years, the space between the trunks was filled with some tree generations of beech in order to minimise growth of shoots from dormant buds. (3) Selective thinning and shelter wood selection: Such thinning resulted in production of stands which were not of uniform age; only some of the trees were removed according to their size and usefulness and the distribution of the diameters of the trunks left standing remained constant. Regeneration in selectively thinned forests took place where the individual trees were removed. In sheltered woods regeneration occurred on areas where groups of trees had been harvested. Because of the difference in light and size of the regeneration area a species-rich and multi-storey, economically but sustainable exploited forest cover resulted.
ARD: Afforestation, reforestation and deforestation attained particular significance in the Kyoto Protocol (see Chap. 5). Deforestation refers to changing forest into other forms of land use (e.g. roads), reforestation is establishment of forests on areas which had been forests earlier (e.g. planting of forests on valley meadows), afforestation means establishment of forests on land which had not been forested earlier (e.g. forests on moorlands). Revegetation is the re-establishment of forests on areas which had been free of vegetation (e.g. slag heaps). Degradation is use of wood in excess of growth, that is the number of individual trees clearly falls below the limit set by self-thinning and density of the stand which would have occurred with maximal growth. The current definition of a forest (10-30% cover, 24 m high) allows degradation to these limiting values before conversion (e.g. from primary to secondary forest or to plantations). Harvests are currently classified not as emissions in the calculations, as it is linked to regeneration of stands in normal forest management.
Economically productive grasslands: This term refers to areas of grass, used for production of hay or for grazing. In Germany these grasslands occur mainly on heavier (clay) soils which are difficult to plough in spring, or on areas where the growing period for cereals is too short (mountain meadows). The species richness of such grasslands depends strongly on the intensity with which they are used (number of mowings, fertilisation, etc.; Ellenberg 1996).
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