236 How to Balance Forestry and Biodiversity Conservation

How to balance forestry and biodiversity conservation – A view across Europe

236 Kottenforst – The Regional Forest District Office Rhein-Sieg-Erft: forestry, nature conservation and recreation in urban areas C 4 U. Schölmerich¹, K. Striepen² ¹ Head of the Regional Forest District Office Rhein-Sieg-Erft, Germany ² Project Manager LIFE+ Project ‘Ville Forests‘, Germany

Aims of the enterprise services for society in the long term. Recreation, nature conservation and wood production are The aim of our forest management is to increase always considered but may be given different pri- forest resilience against climate change impacts in orities depending on the geographic location of order to guarantee all relevant forest ecosystem the forest area.

Germany

N km 0 0,5 1 2 3 4 5 Sources: Esri, Airbus DS, USGS, NGA, NASA, CGIAR, N Robinson, NCEAS, NLS, OS, NMA, Geodatastyrelsen, Rijkswaterstaat, GSA, Geoland, FEMA, Geoland, GSA, Rijkswaterstaat, NMA, Geodatastyrelsen, OS, NLS, NCEAS, Robinson, N CGIAR, NASA, NGA, USGS, DS, Airbus Esri, Sources: Community User GIS the and contributors, OpenStreetMap © USGS, NOAA, FAO, Garmin, HERE, Esri, Sources: community; user GIS the and Intermap

< Fig. C 4.1. The Kottenforst in the foreground and the city of Bonn with the high tower in the background shows the interface between forest, landscape and densely settled area in the ‘Rhein-Sieg Erft’ close to Bonn and Cologne (Photo: Klaus Striepen).

237 Timber/Biomass

Groundwater Non-timber products

Statement Climate Erosion “Combining forestry, nature conservation and recreation in urban areas.” Landscape Protection

Recreation Biodiversity

Table C 4.1. Key figures: Regional Forest District Office Rhein-Sieg-Erft (state forest).

Forest community Mixed oak – beech forest in both lowlands and low mountain ranges Total forest area Forested area 211 km²/non-wooded areas 20 km² Main management types 94 % high forest; 1 % coppice with standards, 5 % without management Total volume 206 m³ under bark/ha (4 339 459 m³ under bark) Annual growth 7.6 m³ under bark/ha (159 692 m³ under bark) Annual use 4 m³ under bark/ha (85 000 m³ under bark) according to the latest forest management plan Altitude 100 to 400 a.s.l. Ownership State of North Rhine-Westphalia Geology Right bank of the Rhine: Rhenish Slate Mountains Left bank of the Rhine: Lower, Mid and High Rhine Terraces Protected area (total) 144 km² Nature protection area (Natura 2000) 106 km² Protective function Protection forests: against noise and emissions

Background 200 m above sea level. It is characterised by varying, small-scale site conditions. The mild sub-Atlantic cli- The Rhineland in the west of North Rhine-West- mate with an average annual temperature of about phalia is one of the most populous regions in Ger- 10 °C displays slightly continental characteristics many. The area of the Forest District Office includes with low annual precipitation of 600 mm. Mixed the cities Cologne and Bonn as well as the counties oak (Quercus spp.) forests (fig. C 4.2), lowland ‘Rhein-Sieg’ and ‘Rhein-Erft’. Altogether 2.4 million beech (Fagus sylvatica) forests and mixed conifer- inhabitants live in cities and counties correspond- ous and broadleaved forests with Norway spruce ing to about 40 people for each hectare of forest. (Picea abies) and Douglas fir (Pseudotsuga men- The Forest District Office manages all forests owned ziesii) prevail depending on edaphic conditions. In by the state of North Rhine-Westphalia and offers the northwest there are also extensive areas that services to both private and municipal forest own- have been afforested following extensive brown ers. It implements tasks as set out by the forestry coal mining. authority. East of the Rhine, the Rhenish slate mountains Two types of landscapes are typical for the dominate. The altitude rises rapidly to 400 m. In region. In the west, the terraced landscape of the weather exposed areas, annual precipitation can Rhine Valley lies at an altitude of between 100 and reach up to 1000 mm, while the average annual

238 C 4 Kottenforst, Germany

Fig. C 4.2. Mixed oak forest in the Rhein-Sieg-Erft Regional Forest District Office (Kottenforst near Bonn) (Photo: Klaus Striepen). temperature drops to 8 °C. Soils are alkaline and by the foresters of the Rhein-Sieg-Erft Regional nutrient poor and thus characterised by beech with Forest District Office. a few sessile oaks (Luzulo-Fagetum) and extensive spruce forests. Table C 4.2. Tree species distribution in the Rhein-Sieg- In the Rhine Valley, human influence has Erft Regional Forest District Office (state forest). shaped the landscape especially around metropoli- Tree species ha tan areas. The main challenges include not only the Oak (Quercus robur, Q. petraea) 4625.0 fragmentation of forests and their intensive use for Beech (Fagus sylvatica) 4229.4 recreation, but also the increasingly critical attitude Poplar (Populus spp.) 634.0 of the urban population towards the wood use. Other broadleaves 4193.6 Norway spruce (Picea abies) 4400.4 Scots pine (Pinus sylvestris) 1725.7 Portrait Douglas fir(Pseudotsuga menziesii) 692.3 Larch (Larix decidua) 767.0 Ownership structure The total forest area in the forest district is 620 km². The highest proportion is private forest (43 %), fol- lowed by state forest (38 %), municipal forests Forest history and cultural heritage (14 %), and federal forest (5 %). The high propor- The oldest settlements in the Rhine Valley date tion of small private forest properties is characteris- back 7000 years to the Neolithic era, and the region tic of the ownership in the region, and 53 % of the has been continuously inhabited since Roman forests are less than 20 ha. The private forest own- times. Throughout the centuries, people have ers are organised into 16 Forest Management Asso- worked and shaped the forests according to their ciations, and in 2018 14 of these associations (rep- needs. From the Middle Ages to the Napoleonic resenting about 4000 forest owners) were serviced period, many woodlands were owned by the

239 How to balance forestry and biodiversity conservation – A view across Europe church, such as the Kottenforst to the west of Bonn The Regional Forest District Office is the initia- or the Königsforst on the outskirts of Cologne. tor and partner in large-scale nature conservation Owing to the importance of forests for supplying projects, such as: the European LIFE+ project ‘Ville timber to these cities and serving as the hunting Forests – LIFE forests and waterworlds’ and the Fed- grounds of the ‘Electorate of Cologne’, the forests eral project ‘Chance 7’ funded by the Federal Pro- have preserved their characteristics over the centu- gramme for Biological Diversity. ries and are characterised by a high level of habitat continuity. The special cultural and historical signif- Population and recreation icance of this forest is documented in the redesign About 2.4 million people live in the Cologne/Bonn of the Kottenforst as a ‘par force’ (the ritualised region, and forests represent important retreats hunting of game by the nobility) hunting area by from the rush and noise of the cities. The ‘peace Clemens August of Bavaria (Archbishop-Elector of and quiet’ of the forests has been shown to have a Cologne) in the middle of the eighteenth century. positive effect on people’s health. Good access to The star-shaped network of forest roads is pre- forests makes them a prime location for recrea- served to this day. tional sports. The near-natural of these forests also offer visitors the chance to experience nature and Nature conservation thus counteract the alienation of the urban popu- About 62 % of the state forest managed by the lation from nature. The number of forest visitors is Regional Forest District Office Rhein-Sieg-Erft is pro- high, especially at weekends. However, their tected either as nature reserves or Natura 2000 demands vary considerably. They range from the areas, and thus the area has a crucial role in protect- desire for an undisturbed nature experience to the ing biodiversity in the region. Protected areas of demand for well-developed and accessible forests European significance include: (i) the old beech for- for family outings and sports activities. Such inten- ests in the ‘Siebengebirge’ near Bonn, (ii) Atlantic sive leisure time use can lead to possible conflicts heaths and oak forests on sand dunes in the ‘Wah- with conservation objectives, and in turn can lead ner Heide’ and (iii) mixed oak forests in the to questions concerning the type and intensity of ‘Villewälder’ between Cologne and Bonn. Manage- forest management. To address such conflicts, the ment of protected forest areas is based on Natura Regional Forest District Office pursues various 2000 management plans. This includes the promo- approaches, ranging from public relations work tion of natural forest communities and the safe- throughout the whole region to a wide range of guarding of old trees and deadwood in managed forest related educational services and activities. forest stands. To promote natural forest develop- The office cooperates with three information cen- ment, the harvesting and extraction of wood is com- tres, namely ‘Haus der Natur’ in Bonn, ‘Steinhaus’ pletely banned in an area of 1862 ha (wilderness in Bergisch-Gladbach, and the exhibition of the development areas, strict forest reserves). The old- ‘Verschönerungsverein für das Siebengebirge’ in est forest areas in which natural development pro- Königswinter. New educational tools, so-called cesses are protected were already set aside in 1970. ‘outdoor forest classrooms’, or Marteloscopes, are The conservation of old trees and deadwood is also applied for public outreach. also carried out outside protected areas to safeguard biological diversity. This is implemented by the Forest Service of North Rhine-Westphalia (Wald Economy und Holz NRW) based on the Tree-Biotope-Concept ‘Xylobius’. An aim of management is either a total The State Forest Enterprise in North Rhine-West- deadwood volume of 40 m³/ha or 10 biotope or phalia derives about 70 % of its income from wood habitat trees/ha in all forest stands with near-natu- products (fig. C 4.3), and 30 % from non-wood ral tree species composition and an age of above products such as rentals, leasing, hunting, fishing, 120 years (for oak forests above 140 years). Biotope transfer revenues, eco-points, and the sale of wood is defined as trees with cavities or nests, as seeds. The total revenue of the enterprise is in the standing or lying deadwood, or trees displaying magnitude of 20–50 €/ha. A number of ecosystem (potential) habitat features as well as ancient/mon- services can be only partially marketed in Ger- umental trees. many. For example, owing to the free right of

240 C 4 Kottenforst, Germany

Fig. C 4.3. High-quality timber is marketed mainly through submission sales (i.e. the public announcement of timber for sale and the offers for the timber) (Photo: Klaus Striepen).

access to forests, visitors are not charged for recre- nue as compared to its area share. This is due to a ation. generally low prices for hardwood and the high Integrated management often leads to good proportion of non-marketable assortments. results. It can, however, cause lower revenues and additional costs as for example, by preserving old trees and leaving large amounts of deadwood in Example Kottenforst near Bonn – Finding the forest. Additional costs can also arise when the balance applying, for example, more expensive timber harvesting methods to support soil protection. One of In forests close to cities, wood production, nature the benefits of such approaches is that they help to conservation and recreation need to be adequately improve public acceptance for forestry measures, in considered. Each forest area poses its own chal- this timber extraction. lenges, making it necessary to apply tailored solu- The Rhein-Sieg-Erft Forest District Office bene- tions. This is illustrated by an example from the fits from easy access to high-quality seed stands Kottenforst forest area near Bonn. The following and seed plantations, which is a unique situation statements refer only to the Kottenforst state for- for North Rhine-Westphalia. The favourable loca- est situated in the Rhein-Sieg-Erft Forest District tion also makes the sale of firewood to the end Office (fig. C 4.7) consumer an important source of income. The Kottenforst is one of the most important The proportion of spruce in the state forest will oak forests in North Rhine-Westphalia. Oak and decline drastically in future as a consequence of the beech are up to 250 years old. The forest is located predicted increase in the frequency and severity of at the gates of the city of Bonn and covers an area storms, heatwaves, drought, and bark beetle infes- of about 4000 ha. The altitude is approximately tations. Such developments will have negative 170 m a.s.l., with an annual average temperature effects on income, as coniferous wood currently of 9.4 °C and annual precipitation of 670 mm. The contributes considerably more to the overall reve- dominant soil type is moderately base-rich, heavily

241 How to balance forestry and biodiversity conservation – A view across Europe waterlogged pseudogley derived from Löß overlay- with the integration of nature conservation aspects. ing glacial terrace gravel of the Rhine. As the occur- The structural diversity of these oak forests and rence of oak-hornbeam forests on temporarily wet their large amounts of old trees and deadwood are sites is of Europe-wide significance, the core area decisive factors that safeguard species diversity has been protected as a Natura 2000 site since 1999. under this management scheme. The Kottenforst is habitat for protected species of European interest including the middle spotted Preserving old trees and deadwood woodpecker (Dendrocoptes medius) (fig. C 4.5a), Combining unmanaged and near-natural forest the Bechstein‘s bat (Myotis bechsteinii) (fig. C 4.5b), stands serves as the basis for preserving old trees the stag beetle (Lucanus cervus), and the wildcat and standing and lying deadwood. Timber removal (Felis silvestris). At the same time, it is one of the is banned on 235 ha of ecologically valuable forest most important areas for amphibians in North areas. These areas are left to develop freely with- Rhine-Westphalia with occurrences of agile frog out human intervention and serve as a retreat for (Rana dalmatina) and crested newt (Triturus crista- animal, plant, and fungal species, that are closely tus). linked to old-growth and decay phases. Further The main management aim in Kottenforst is they act as so-called donor stands for enhancing the production of high-quality oak timber along the spread of such species to neighbouring com- mercially managed forests. Managed forests of oak and beech are enriched Table C 4.3. Key figures of the forest district Kottenforst with old trees (fig. C 4.6.) and deadwood once near Bonn (state forest). they reach an age of 100 years. For this purpose, 10 habitat trees per hectare are selected and Oak-hornbeam (Quercus marked. These trees are left to develop without robur-Carpinus betulus) forest Forest community admixed with small-leaved lime intervention and will not be harvested. The distri- (Tilia cordata) and beech (Fagus bution of these habitat trees is not uniform in all sylvatica) on waterlogged soil stands but takes into account both their ecological Total forest area 3900 ha importance in terms of the occurrence of protected State forest area 2400 ha animal and plant species and their economic value. Main management 89 % high forest; 1 % coppice with A number of additional protective elements types standards; 10 % no management have also been applied. Particularly valuable old Total volume 225 m³/ha forest stands larger than one hectare have been Annual growth 7.9 m³/ha protected as so-called ‘wood island biotopes’ or Annual use 4.1 m³/ha ‘stepping stones’. Interventions directed at the con- Nature protection servation of ecologically valuable old oak trees 2456 ha area (Natura 2000) under competition from beech and hornbeam are allowed. If such measures are no longer acceptable for reasons of worker safety the stand is temporarily left for free development until the old trees in 11 the stand are well into the decay phase. To locally increase the amount of deadwood, cohorts of 10 to 15 15 trees have been identified as so-called ‘biotope tree groups’. These groups were mostly clumped 38 around already designated habitat trees. The groups were established mainly in stands with low Oak wood quality and sufficiently far from frequently Beech 17 used hiking trails to ensure public safety. Particular Other broadleaves attention was given to protecting valuable tree 19 Spruce microhabitat structures such as tree cavities or Other coniferous severe tree damage (e.g. crown breakage, cankers), Fig. C 4.4. Tree species composition of the state forest standing large deadwood, and veteran/ancient area of Kottenforst (in %). trees.

242 a b

Fig. C 4.5. The middle spotted woodpecker on an old oak tree and on the left a Bechstein‘s bat in a hollow oak (Photos a: Klaus Striepen and b: Martin Koch).

Expanding natural forest communities The state of North Rhine-Westphalia aims at increasing the proportion natural forest communities to meet the conservation goals of the Natura 2000 areas in the long term. At present, the proportion of coniferous forest e.g. in Kottenforst is still at 26 %. This relatively high proportion is because of the large pure Norway spruce stands, which have often been planted on unsuitable waterlogged soils. These stands are being converted towards more climate-stable mixed oak stands. Dying spruce stands are regenerated with pedunculate oak (Quercus robur) and other suitable tree species. This will help to achieve the protection objectives of promoting oak forest habitat types and better adaptation of forests to the effects of climate change. Managing those stands towards high-quality oak assortments will also create a favourable economic return in the long term.

Minimising human disturbance Anthropogenic impacts on forest sites are being reduced e.g. by dismantling old drainage ditches. The competitiveness of pedunculate oak is thus improved as beech is more sensitive to waterlog- ging. Measures like these, support the conservation of protected forest habitats. The removal of ditches also reduces surface runoff after heavy rainfall and improves water supply of forest stands during dry Fig. C 4.6. Large tree cavities such as the one found on summers, yet another contribution to the adapta- this 180-year-old oak are rare as they require many tion of forests to the consequences of climate decades to develop and are thus of particular ecological change. importance (Photo: Klaus Striepen).

243 How to balance forestry and biodiversity conservation – A view across Europe

Fig. C 4.7. Biodiversity concept for the Natura 2000 area ‘Forest Reserve Kottenforst’.

Promoting coppice with standards as tall oat-grass (Arrhenatherum elatius), bristle Coppice with standards is a traditional form of for- mat-grass (Nardus stricta) and moor grass (Molinia est use in Kottenforst. It was abandoned in the caerulea) meadows with occurrence of Arnica middle of the nineteenth century. Today, only a (Arnica montana), Devil’s-bit (Succisa pratensis), few oak and beech trees remind us of this tradi- and various orchid species. tional form of forest management. Owing to the importance of open, sunlit forests for many plant, Informing forest visitors animal, and fungal species, selected stands have The forest area is located about 10 km from the city been transformed to coppice forests. Such stands centre of Bonn and serves as a local recreation area allow visitors to experience this traditional form of of outstanding importance. To sensitise visitors to forest management and the biodiversity associated the vulnerability of forest ecosystems and their with it. numerous habitats, the Rhein-Sieg-Erft Regional Forest District Office engages in comprehensive Safeguarding forest habitats public relations work. Jointly with the City of Bonn An important component of the protection con- the Regional Forest District Office operates the for- cept is the conservation and promotion of small- est information centre ‘Haus der Natur’ (House of scale habitats within forests. Examples are the Nature). In addition to the permanent exhibition maintenance of small water bodies serving as habi- ‘Großstadtwald’ (city forests), the forest informa- tats for amphibians, dragonflies, and water dwell- tion centre offers guided tours and workshops ers, and the extensive use of species-rich forest (fig. C 4.8). meadows. The forest meadows include such species

244 C 4 Kottenforst, Germany

Fig. C 4.8. Guided excursion in the Kottenforst, where interested visitors learn about tree microhabitats (Photo: Klaus Striepen).

European funding helps For more information The nature conservation concept has been imple- www.wald-und-holz.nrw.de/ueber-uns/einrichtungen/ mented between 2014 and 2020 as part of the regionalforstaemter/rhein-sieg-erft LIFE+ nature conservation project ‘Ville Forests – www.wald-und-holz.nrw.de/naturschutz/xylobius-lebens- raum-bewahren LIFE forests and waterworlds’. The project is coordi- www.villewaelder.de nated by the Rhein-Sieg-Erft Regional Forest Dis- www.chance7.org trict Office in cooperation with the conservation organisation Biologische Station Bonn / Rhein-Erft e.V. The project budget is € 3.3 million, half of which is financed by North Rhine-Westphalia Minis- try of the Environment. The remaining funds are provided by the European Union.

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