© AFSV; Waldökologie, Landschaftsforschung und Naturschutz (Forest Ecology, Landscape Research and Nature Conservation) - Heft 14, 2014
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Impressum und Inhaltsverzeichnis
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REIF, A., SCHULZE, E.-D., EWALD, J., ROTHE, A.: Waldkalkung – Bodenschutz contra Naturschutz?
(Forest liming – soil protection versus nature conservation?)
The deposition of strong inorganic acids in forests leads to low pH values and high concentrations of Al3+ in the soil. Forest liming neutralizes acidity and leads to an increase in base cations. Additionally, surface organic layers decay more rapidly and stored nutrients are mobilized. The ground vegetation responds to liming with an increase in nutrient-loving species and a decline in acidophytes. The mycorrhizal fungi and soil fauna species composition change dramatically. Tree roots, at least initially, retreat from the topsoil. It takes several years for the base cations to reach the deeper soil horizons (up to about 30 cm) and they rarely go deeper. Since 1990 sulfur deposition has greatly declined. However N deposition rates remain at high levels (conifer stands > deciduous > open areas). High N inputs continue to contribute to soil acidification and at the same time cause the eutrophication of forest ecosystems which are naturally N-limited. The increased rate in forest growth results in an increased need for other nutrients. In many forests, the critical deposition threshold (“critical load”) of approximately 10 to 20 kg N ha -1 yr -1 has been exceeded. In stands where the soils are supersaturated with nitrogen, the nitrate which is not retained by the humus or assimilated by the forest vegetation leaches into the ground water. Up until today in Baden-Wuerttemberg, Rhineland-Palatinate, Hesse, Lower Saxony, North Rhine-Westphalia, Thuringia and recently in Saxony-Anhalt large areas of forest have been limed using three to four tons of dolomitic lime per hectare per decade. The aim is to prevent the ongoing acidinduced degradation of clay minerals in order to increase forest vitality. Often P and / or K are added to the lime. Bavaria, Brandenburg and Mecklenburg-Western Pomerania either do not lime their forests or only do so in a very restricted manner. In these states the central European tree species beech, spruce, Scots pine, fir and oak growing there are no less vital than elsewhere. These tree species grow in a wide range of ecological soil types. Analyses of leaves and needles show that a small, but adequate nutrient supply exists even in the most acidic forest soils. Today it is not soil acidification but eutrophication (and climate change) which are the main threats to forest ecosystems, especially for oligotrophic communities on sandy soils. Liming in eutrophic forests counteracts acidification and eventually leads to deeper rooting. But it also increases nitrogen availability and other limiting nutrients and adds to the process of eutrophication. Therefore, the results evaluating of the effects of liming are ambivalent. The problem can only be solved by a reduction in N deposition. From a nature conservation standpoint it is of particular concern that liming is done on oligotrophic forest communities which are naturally low in base substrates. These habitats need to be protected from the addition of lime. In mesotrophic clay soils susceptible to acidification, liming can be occasionally tolerated. The enrichment with P and K means fertilisation and is therefore not acceptable. In order to weigh the impacts of forest liming, unlimed control plots should be established. In the light of today’s relatively high forest growth rates further funding for forest liming should be reassessed.
>> Volltextversion (pdf 9.0 M; Heft 14-Aufsatz 2; Original paper; Language: Deutsch; urn:nbn:de: 0041-afsv-01423)
|Waldentwicklung und Landnutzungswandel
SEILER, U., WALZ, U.: Rekonstruktion der Waldentwicklung aus Forsteinrichtungswerken und historischen Karten - Ein Beitrag zur Untersuchung des Landnutzungswandels in der Nationalparkregion Sächsische Schweiz
( Reconstruction of forest development based on forest management plans and historical maps A contribution to research on land use change in the Saxon Switzerland national park region)
Forest is commonly perceived as a natural landscape element, which, in contrast to other anthropogenic forms of land use, persists over long periods of time. Yet the woodlands of Central Europe have in fact undergone major structural transformations as a repercussion of centuries of shifting land use. Using historical and current forest management plans as well as other historical maps, such changes have been analysed to a high spatial precision for the national park region of Saxon Switzerland over the timeframe of the past two hundred years. The main purpose of this work is to check the suitability of historical forest maps for digitization, and thereafter to analyze the resulting datasets to derive new information on the structural changes of woodland. The conclusions were linked to findings on spatial changes in forest cover within the Saxon Switzerland national park. The results show that the generated data can be used as a basis for the spatial-statistic analysis of woodland development, resulting in quantitative as well as qualitative statements on structural changes as well as changes in patterns of forest usage. Analyses based on historical topographic maps show that in the period from 1780 until today the extent of forest coverage has dropped only minimally from 60 % to 56 %. However, some large-scale felling of woodland can be observed at the edges of clearings as well as reductions in small, isolated stands situated in open land. On the other hand, reforestation measures are evident in former small glades within large closed stands. A comparison of the relative coverage of individual age classes and groups of tree species as derived from forest maps produced quantifiable statements on developments such as the increase of old-age stands in the national park or a reduction of silver fir over the entire national park region. High-resolution analyses were undertaken in order to detect changes in the distribution of the various tree species, for example allowing a reconstruction of the developments leading to the currently very low occurrence of silver fir. Such analyses also pinpoint which tree species have replaced the traditional silver fir found in this area. Results show that the intensification of forest management at the beginning of last century created stands which were little suited to the respective location. In the meantime, however, we can detect structural changes in terms of the composition of species and age classes towards a near-natural state. A considerable benefit of such investigations is that generated data can be used to scrutinize the formulation of development goals as well as supporting the planning of forest maintenance and development.
>> Volltextversion (pdf 7.0 M; Heft 14-Aufsatz 4; Original paper; Language: Deutsch; urn:nbn:de: 0041-afsv-01444)
BALLA, S., BERNOTAT, D., FROMMER, J., GARNIEL, A., GEUPEL, M., HEBBINGHAUS, H., LORENTZ, H:, SCHLUTOW, A., UHL, R.: Stickstoffeinträge in der FFH-Verträglichkeitsprüfung: Critical Loads, Bagatellschwelle und Abschneidekriterium
(Nitrogen deposition in appropriate assessment under Article 6 (3) of the Habitats Directive: Critical Load, thresholds of insignificant impacts, and bagatelle)
For the last ten years impacts from nitrogen deposition within appropriate assessments has been a controversial issue discussed by many experts in Germany. More recently results from a R&D project funded by the Federal Highway Research Institute (BASt) have been published to establish a method on the assessment for road projects. Adverse effects are assessed in a staged approach based on the concept of critical loads: if total environmental deposition is lower than critical loads of the most sensitive feature of the site, no likely significant effects have to be expected. Project contributions up to a de-minimis value of 0.3 kg N ha-1 y-1 are considered as being too small to be measurable. Neither could nitrogen deposition of up to this value be detected in the field nor could damages be attributed to projects contributing such small amounts. Project contributions lower than the proposed threshold thus exert only hypothetical risks that do not justify or even demand refusals of project under Article 6.3. Only project contributions above the cut off criterion have to be considered within an appropriate assessment in combination with other projects. With view on the protected site another threshold of 3 % of the critical load is applied that can be exceeded not only by single projects but also in combination. Its application does not depend on background deposition. It depends on the specific sensitivity of the habitat precautionarily described by critical loads. Examination of scientific results on the effects,particularly along roads has shown that a value of 3 % of a particular critical load clearly lies below detectable adverse effects on the conservation status of natura 2000 habitats. Both thresholds are very low and thus in line with the precautionary approach prescribed by the Habitats Directive. The assessment approach encompasses legal as well as scientific confidence. It also adheres to the principle of proportionality and has proven to be functional in practice. As nitrogen inputs up to 0.3 kg N ha-1 y-1 cannot be realistically attributed to a particular project, they should rather be described as diffuse part of the background deposition. High background deposition in turn should be lowered by the most efficient measures to stay in accordance with the requirement under the Habitats Directive to avoid deterioration. Very small project contributions as accepted by the proposed process will not constitute an obstacle for this.
>> Volltextversion (pdf 1.5 M; Heft 14-Aufsatz 3; Original paper; Language: Deutsch; urn:nbn:de: 0041-afsv-01430)
WALENTOWSKI, H.; SIMON, A.: Wälder der Alpinen Biogeograpischen Region – aus der Naturwaldreservatsforschung abgeleitete Erkenntnisse für ein staatenübergreifendes Natura 2000-Management
(Forests of the Alpine Biogeographic Region – insights from forest reserve research applicable to the cross-border management of Natura 2000 sites)
We conducted an analysis of 45 reléves in the two forest nature reserves in the Bavarian Northern Limestone Alps designated for long-term research. The Totengraben reserve is located in the Fauna-Flora-Habitat (FFH)-area of the Mangfall Mts., and the Wettersteinwald reserve in the FFHarea of the Wetterstein Mts. The aim of the study was to develop a management-focused, cross-border forest typology grounded in geobotany, conservation, and site-specific ecological principles. We made use of the recently implemented Bavarian Forest Reserve Research programme to survey six permanent 314 m2 circular vegetation plots within the core areas of the reserves. The newly collected data were combined with existing data. The two reserves include the following forest types: upper montane, closed mixed coniferous forest; lowermost semiclosed subalpine spruce forest; and uppermost semi-open subalpine Swiss stone pine forest. The forests near the alpine timberline have been heavily disturbed by centuries of cattle grazing, allowing a massive expansion of secondary rhododendron-mountain pine shrubs. Our findings make possible the conceptualization of a distinction between areas dedicated to conservation and management in the surrounding FFH areas. The mixed coniferous and the subalpine coniferous forest types on sites with higher soil water storage capacity show lower ecological sensitivities for wood biomass utilization. Outside of the reserves, a sustainable forest management plan allowing for multiple forest functions is feasible, provided that some small stands of these types remain unused and may serve as crucial refugia and habitat stepping stones to harbour core populations of relict species. Mixed coniferous and subalpine coniferous forests on shallow, well-drained calcareous sites, in contrast, show high ecological sensitivities for wood biomass utilization and require an especially careful minimum intervention or even a non-intervention management. The geographical information system WINALP can be used to elucidate type-related priorities.
>> Volltextversion (pdf 10.7 M; Heft 14-Aufsatz 5; Original paper; Language: Deutsch; urn:nbn:de: 0041-afsv-01457)
DIEMANN, R.: Ein deutsches Gelehrtenleben im 20. Jahrhundert: Dem Bodenkundler Prof. Dr. Ernst Ehwald zum 100. Geburtstag am 11. August 2013
>> Volltextversion (pdf 1.5 M; Heft 14-Aufsatz 1; Original paper; Language: Deutsch; urn:nbn:de: 0041-afsv-01419)