UCD Forestry Excursion to the Black Forest, Germany April 2 - 8, 2006
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UCD Forestry Excursion to the Black Forest, Germany April 2 - 8, 2006 Paul Gardiner Joe Codd Ellen O’Brien Sharron Daly Martin Quigley Simon Fortune Tara Ryan Barry McCann Vincent Upton Luke McGurdy Individual reports were submitted as part of the 4th year of the Honours Degree Programme in Forestry, University College Dublin. Compiled and edited by Maarten Nieuwenhuis. Introduction to the Black Forest and forestry in Germany Natural Conditions The Black Forest and surrounding area have a predominantly sub-Mediterranean to warm temperate climate, with 80% of all winds and storms coming from a western direction. This results in a mild, wet and humid climate. At regular intervals of 10, 20 or 30 years, the climate is strongly influenced from the east, resulting in dry, hot summers and extremely dry and cold (-35oC) winters. The Black Forest has the potential to support approximately 620 tree species, but the intermittent continental influences from the east kill much of the cold sensitive vegetation. The Black Forest was affected by the last ice age, resulting in the loss of many tree species and consequently few native species remain. Scots pine (Pinus sylvestris), oak (Quercus spp), beech (Fagus sylvatica), and elm (Ulmus glabra) all occur naturally in the area at varying altitudes and soil qualities. Beech occurs in both the uplands and lowlands, as long as the site is relatively fertile with a high level of humidity. Black Forest History Before the invasion by the Romans, approximately 99% of the area was covered with natural beech forest. By the time of the invasion of the Germanic tribes approximately 40% of forests had been cleared. Monasteries (many of which owned forests) and cities then began to develop and by 1300 70% of forests had been cleared for agriculture with forests remaining only in areas where agriculture was not possible. Forests were used for the following five hundred years as a source of construction timber, fuel and as areas for animal rearing. Many forests at this time were managed using the coppice system. By the beginning of the 18th century, forest quality had also begun to deteriorate. During the 18th century many industries began to develop. Charcoal was used by many of these industries and therefore large quantities were required. No replanting was undertaken and natural regeneration was prevented due to 2 browsing animals. This resulted in a severe lack of forests by the end of the 18th century, with wind and water erosion commonplace. The advent of Napoleonic rule resulted in great land reform in Germany – which up until this time had consisted of many small and fragmented territories. Land and forests were re-distributed among private owners (mainly farmers), with the remote forests remaining in the ownership of the state. Community forests were established around some cities. This has resulted in 50% private, 20% community and 30% state forest ownership in Germany (with these proportions varying from region to region), with all forests managed under the umbrella of the state (Lander) forest service. Individual farmers were given free plants for reforestation and were trained by state foresters in forest management skills, and so a strong tradition of forestry has existed since this time. When Freiburg was founded in 1120, 3,500 ha of forest were already given to the city, and people were allowed to use this forest for firewood collection. Since then, further areas have been added, resulting in a forest of 8,000 ha, one of the largest community forests in Germany. Bare land, cut-over areas, coppice forests and high forests remaining at the end of the 18th century went through a number of management programmes to transform them into mixed pioneer forests, even-aged pure conifer stands, broadleaved pure forests and mountainous mixed forests that are present in the Black Forest today. These programmes consisted of natural succession, afforestation, conversion/transformation and natural regeneration, respectively. With the changes in management, the function of the forests also changed (Table 1). Even-aged pure conifer stands still dominate the Black Forest area. The reduction in timber prices and the uneconomic outlook for forestry in the 1960s led to an increase in the multi-functional aspects of forests. However, once again, wood energy is becoming popular, as a result of high energy prices. Forest cover is approaching almost 90% in some regions of the Black Forest as a consequence of the move away from agriculture in the remoter valleys. 3 Table 1 Forest function in Germany through the ages. Function Yield Period Multi-functional Firewood, timber, fruits, resin, forest To the middle of pasture, game the 19th century Mono-functional Construction and industrial timber 1850 to 1970 Multi-functional Construction and industrial timber, 1970 - present landscape protection, recreation, water/nature protection, erosion control Many positive developments have taken place with regard to German forests and forest management over the last two centuries. These are: • Abolishment of user rights (such as litter removal) in forests and the reform in property rights; • Improvement in forest infrastructure; • Development of seed supply and nursery enterprises; • Development of effective harvesting methods and forest training systems; and • Development of forest research organisations. Species Composition Species composition varies in different parts of Germany but is largely dominated by Norway spruce (Picea abies) and Scots pine (Pinus sylvestris). The overall species composition is shown in Table 2. There is now a move away from planting Norway spruce and Scots pine in an effort to increase other species, especially broadleaves. Severe storms and fire also play a role in determining species composition. Between 1967 and 1999 approximately 330 million m3 of roundwood has been windthrown during intermittent storms. Between 1981 and 1990 5,500 ha of forest were damaged by forest fires. In general, mixed and broadleaf stands are more stable than pure conifer stands. 4 Table 2 Species composition of German forests. Species % of area Norway spruce 28 Scots pine 23 silver fir 2 Douglas fir 2 larch 3 beech 16 oak 9 broadleaf ‘hardwoods’ (ash, maple, sycamore) 7 broadleaf ‘softwoods’ (birch, alder, poplar) 10 Problems in German forestry A major problem existing in German forestry is a high proportion of conifer stands that are not suited to their site. Conifer volume production seems to be a priority over quality and many young stands are over stocked and unstable due to late thinning (due to high labour costs). This is clear from the excess of annual increment over annual cut (Table 3). Tree growth is also changing due to longer growing seasons brought about by global warming, and increased levels of nitrogen deposition. Table 3 Annual cut and increment in German forests (1999). Annual increment Annual cut million m3 W. Germany 95 50 E. Germany 35 15 Total 130 65 Problems also exist regarding the sale of small and very large diameter timber, as the markets for these assortments is small. The general public opinion is that forestry is 5 not an industry, compared with say car and machine manufacturing; forests are regarded solely as a place for recreation and amenity. The Black Forest: location and composition The Black Forest is located in the south-west of Germany. It is separated from the Vosges mountain range in France by the Rhine valley. The Black Forest bedrock is mainly granite, with small amounts of sandstone (a popular building stone in the city of Freiburg) and limestone on top. Parts of the granite massif have been transformed into gneiss due to severe tectonic pressure. The tectonic activity has also given rise to hot springs along the Rhine valley, traditionally used for spas, and now beginning to be exploited for thermal energy. The Rhine Valley is extremely fertile due to deposits of loess. The many city in the southern part of the Black Forest is Freiburg. Freiburg Figure 1 Black Forest, location map. Schauinsland Schauinsland is the name of the Black Forest region to the southeast of Freiburg (Figure 2). The highest point is 1284 m. The forests in this area were used as a source of fuel for the lead, zinc and silver mines that operated in the area from the 1700s to 1956. Small communities developed in this area and domestic industries such as clock making developed. Tourism is now one of the major industries in the area, with many 6 traditional farmhouses converted to hotels. Feldberg, 1490 m high, is the highest point in the Black Forest and is located to the southeast of Schauinsland. The average temperature of the Schauinsland area is 4oC with approximately 2,000 mm per annum precipitation, in the form of snow and rain. Crown snap is common due to heavy snow. Trees do not flourish on the western side of the mountain due to the harsh winter weather conditions, but rowan, birch, aspen, sycamore and willow are common in this area, along with some poor quality Norway spruce and silver fir. Spruce and beech are more common on the eastern side where more shelter is available. Excluding the most exposed areas on the top of the mountains, the average rate of growth rate for conifers in this region of the Black Forest is 15 m3 ha-1 yr-1. Forest die-back became a problem in the area in the 1990s and as a result experimental and meteorological stations were set up to monitor the effects of stress caused by severe cold and draught, and by harmful gases (SO2). Clones were used in phenological gardens to assess the reaction to stresses at different elevations. At lower elevations, pasture beech becomes more common. Pasture beech is a mixture of open beech forest and cattle grazing.