@article{HeinrichsAmmerMundetal.2019, author = {Heinrichs, Steffi and Ammer, Christian and Mund, Martina and Boch, Steffen and Budde, Sabine and Fischer, Markus and Mueller, Joerg and Schoening, Ingo and Schulze, Ernst-Detlef and Schmidt, Wolfgang and Weckesser, Martin and Schall, Peter}, title = {Landscape-Scale Mixtures of Tree Species are More Effective than Stand-Scale Mixtures for Biodiversity of Vascular Plants, Bryophytes and Lichens}, series = {Forests}, volume = {10}, journal = {Forests}, number = {1}, publisher = {MDPI}, address = {Basel}, issn = {1999-4907}, doi = {10.3390/f10010073}, pages = {34}, year = {2019}, abstract = {Tree species diversity can positively affect the multifunctionality of forests. This is why conifer monocultures of Scots pine and Norway spruce, widely promoted in Central Europe since the 18th and 19th century, are currently converted into mixed stands with naturally dominant European beech. Biodiversity is expected to benefit from these mixtures compared to pure conifer stands due to increased abiotic and biotic resource heterogeneity. Evidence for this assumption is, however, largely lacking. Here, we investigated the diversity of vascular plants, bryophytes and lichens at the plot (alpha diversity) and at the landscape (gamma diversity) level in pure and mixed stands of European beech and conifer species (Scots pine, Norway spruce, Douglas fir) in four regions in Germany. We aimed to identify compositions of pure and mixed stands in a hypothetical forest landscape that can optimize gamma diversity of vascular plants, bryophytes and lichens within regions. Results show that gamma diversity of the investigated groups is highest when a landscape comprises different pure stands rather than tree species mixtures at the stand scale. Species mainly associated with conifers rely on light regimes that are only provided in pure conifer forests, whereas mixtures of beech and conifers are more similar to beech stands. Combining pure beech and pure conifer stands at the landscape scale can increase landscape level biodiversity and conserve species assemblages of both stand types, while landscapes solely composed of stand scale tree species mixtures could lead to a biodiversity reduction of a combination of investigated groups of 7 up to 20\%.}, language = {en} } @article{LeuschnerWulfBaeuchleretal.2013, author = {Leuschner, Christoph and Wulf, Monika and B{\"a}uchler, Patricia and Hertel, Dietrich}, title = {Soil C and nutrient stores under Scots pine afforestations compared to ancient beech forests in the German Pleistocene - the role of tree species and forest history}, series = {Forest ecology and management}, volume = {310}, journal = {Forest ecology and management}, number = {6}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0378-1127}, doi = {10.1016/j.foreco.2013.08.043}, pages = {405 -- 415}, year = {2013}, abstract = {In the diluvial lowlands of northern Germany, the Netherlands and northern Poland, an estimated similar to 5 Mio ha of Scots pine plantations (Pinus sylvestris) has been established on sandy soil in the last 250 years replacing the former temperate broad-leaved forests after extended periods of cultivation in the Middle Ages. We examined the effect of variable stand continuity of pine plantations (recent vs. ancient: 51-128 vs. >230 years) on the soil organic carbon (SOC) store and soil nutrient capital in comparison to ancient beech forests (>230 years of continuity) which represent the potential natural forest vegetation. Recent and ancient pine stands had c. 75\% larger organic layer C stores than ancient beech forests, while the total C stock in the soil (organic layer and mineral soil to 100 cm) was similar to 25\% larger in the beech forests due to higher C concentrations in 0-50 cm depth of the mineral soil. The soil stores of N-tot were similar to 50\% and the exchangeable Ca, K and Mg pools about three times larger under beech than under the pine stands. Resin-exchangeable P was enriched in the soils under ancient pine stands probably due to manuring in the past. After clear-cut and long cultivation, it may take >230 years of forest presence to restore the greatly reduced mineral soil C and N pools. The C and N sequestration potential of the soils appeared to be particularly small under pine indicating a pronounced tree species (pine vs. beech) effect on soil C and N dynamics. We conclude that, in the face of rising greenhouse gas emissions, the limited soil C and nutrient storage potential of Scots pine plantations on sandy soils needs consideration when selecting suitable tree species for future forestry. (C) 2013 Elsevier B.V. All rights reserved.}, language = {en} } @article{LiangHeinrichSimardetal.2013, author = {Liang, Wei and Heinrich, Ingo and Simard, Sonia and Helle, Gerhard and Linan, Isabel Dorado and Heinken, Thilo}, title = {Climate signals derived from cell anatomy of Scots pine in NE Germany}, series = {Tree physiology}, volume = {33}, journal = {Tree physiology}, number = {8}, publisher = {Oxford Univ. Press}, address = {Oxford}, issn = {0829-318X}, doi = {10.1093/treephys/tpt059}, pages = {833 -- 844}, year = {2013}, abstract = {Tree-ring chronologies of Pinus sylvestris L. from latitudinal and altitudinal limits of the species distribution have been widely used for climate reconstructions, but there are many sites within the temperate climate zone, as is the case in northeastern Germany, at which there is little evidence of a clear climate signal in the chronologies. In this study, we developed long chronologies of several cell structure variables (e. g., average lumen area and cell wall thickness) from P. sylvestris growing in northeastern Germany and investigated the influence of climate on ring widths and cell structure variables. We found significant correlations between cell structure variables and temperature, and between tree-ring width and relative humidity and vapor pressure, respectively, enabling the development of robust reconstructions from temperate sites that have not yet been realized. Moreover, it has been shown that it may not be necessary to detrend chronologies of cell structure variables and thus low-frequency climate signals may be retrieved from longer cell structure chronologies. The relatively extensive resource of archaeological material of P. sylvestris covering approximately the last millennium may now be useful for climate reconstructions in northeastern Germany and other sites in the temperate climate zone.}, language = {en} } @phdthesis{Wattenbach2008, author = {Wattenbach, Martin}, title = {The hydrological effects of changes in forest area and species composition in the federal state of Brandenburg, Germany}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-27394}, school = {Universit{\"a}t Potsdam}, year = {2008}, abstract = {This thesis aims to quantify the human impact on the natural resource water at the landscape scale. The drivers in the federal state of Brandenburg (Germany), the area under investigation, are land-use changes induced by policy decisions at European and federal state level. The water resources of the federal state are particularly sensitive to changes in land-use due to low precipitation rates in the summer combined with sandy soils and high evapotranspiration rates. Key elements in landscape hydrology are forests because of their unique capacity to transport water from the soil to the atmosphere. Given these circumstances, decisions made at any level of administration that may have effects on the forest sector in the state are critical in relation to the water cycle. It is therefore essential to evaluate any decision that may change forest area and structure in such a sensitive region. Thus, as a first step, it was necessary to develop and implement a model able to simulate possible interactions and feedbacks between forested surfaces and the hydrological cycle at the landscape scale. The result is a model for simulating the hydrological properties of forest stands based on a robust computation of the temporal and spatial LAI (leaf area index) dynamics. The approach allows the simulation of all relevant hydrological processes with a low parameter demand. It includes the interception of precipitation and transpiration of forest stands with and without groundwater in the rooting zone. The model also considers phenology, biomass allocation, as well as mortality and simple management practices. It has been implemented as a module in the eco-hydrological model SWIM (Soil and Water Integrated Model). This model has been tested in two pre-studies to verify the applicability of its hydrological process description for the hydrological conditions typical for the state. The newly implemented forest module has been tested for Scots Pine (Pinus sylvestris) and in parts for Common Oak (Quercus robur and Q. petraea) in Brandenburg. For Scots Pine the results demonstrate a good simulation of annual biomass increase and LAI in addition to the satisfactory simulation of litter production. A comparison of the simulated and measured data of the May sprout for Scots pine and leaf unfolding for Oak, as well as the evaluation against daily transpiration measurements for Scots Pine, does support the applicability of the approach. The interception of precipitation has also been simulated and compared with weekly observed data for a Scots Pine stand which displays satisfactory results in both the vegetation periods and annual sums. After the development and testing phase, the model is used to analyse the effects of two scenarios. The first scenario is an increase in forest area on abandoned agricultural land that is triggered by a decrease in European agricultural production support. The second one is a shift in species composition from predominant Scots Pine to Common Oak that is based on decisions of the regional forestry authority to support a more natural species composition. The scenario effects are modelled for the federal state of Brandenburg on a 50m grid utilising spatially explicit land-use patterns. The results, for the first scenario, suggest a negative impact of an increase in forest area (9.4\% total state area) on the regional water balance, causing an increase in mean long-term annual evapotranspiration of 3.7\% at 100\% afforestation when compared to no afforestation. The relatively small annual change conceals a much more pronounced seasonal effect of a mean long-term evapotranspiration increase by 25.1\% in the spring causing a pronounced reduction in groundwater recharge and runoff. The reduction causes a lag effect that aggravates the scarcity of water resources in the summer. In contrast, in the second scenario, a change in species composition in existing forests (29.2\% total state area) from predominantly Scots Pine to Common Oak decreases the long-term annual mean evapotranspiration by 3.4\%, accompanied by a much weaker, but apparent, seasonal pattern. Both scenarios exhibit a high spatial heterogeneity because of the distinct natural conditions in the different regions of the state. Areas with groundwater levels near the surface are particularly sensitive to changes in forest area and regions with relatively high proportion of forest respond strongly to the change in species composition. In both cases this regional response is masked by a smaller linear mean effect for the total state area. Two critical sources of uncertainty in the model results have been investigated. The first one originates from the model calibration parameters estimated in the pre-study for lowland regions, such as the federal state. The combined effect of the parameters, when changed within their physical meaningful limits, unveils an overestimation of the mean water balance by 1.6\%. However, the distribution has a wide spread with 14.7\% for the 90th percentile and -9.9\% for the 10th percentile. The second source of uncertainty emerges from the parameterisation of the forest module. The analysis exhibits a standard deviation of 0.6 \% over a ten year period in the mean of the simulated evapotranspiration as a result of variance in the key forest parameters. The analysis suggests that the combined uncertainty in the model results is dominated by the uncertainties of calibration parameters. Therefore, the effect of the first scenario might be underestimated because the calculated increase in evapotranspiration is too small. This may lead to an overestimation of the water balance towards runoff and groundwater recharge. The opposite can be assumed for the second scenario in which the decrease in evapotranspiration might be overestimated.}, language = {en} } @misc{Heinken2008, author = {Heinken, Thilo}, title = {Die nat{\"u}rlichen Kiefernstandorte Deutschlands und ihre Gef{\"a}hrdung}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-46506}, year = {2008}, abstract = {Nat{\"u}rliche Standorte der Waldkiefer gibt es in Deutschland nur kleinfl{\"a}chig. W{\"a}hrend Kiefernforste anstelle nat{\"u}rlicher Laubw{\"a}lder heute oft landschaftspr{\"a}gend sind, bildet die konkurrenzschwache und lichtbed{\"u}rftige Kiefer ausschließlich auf extrem trockenen oder nassen, n{\"a}hrstoffarmen Standorten naturnahe Schlusswaldgesellschaften. Regionale Schwerpunkte liegen in subkontinentalen Regionen wie dem nordostdeutschen Tiefland und Bayern, ein „nat{\"u}rliches Kiefernareal" l{\"a}sst sich aber kaum abgrenzen. An der Trockengrenze des Waldes finden sich auf Kalk- und Dolomitgesteinen artenreiche Karbonat-Trockenkiefernw{\"a}lder mit Elementen der alpinen Rasen und Kalkmagerrasen in der Bodenvegetation. Diese W{\"a}lder besiedeln steile, s{\"u}dexponierte Felsen und morphodynamisch aktive Bereiche wie Rutschh{\"a}nge und FlussSchotterb{\"o}den im Umkreis der Alpen, kommen aber auch in den Mittelgebirgen vor. Ihr Gegenst{\"u}ck auf sauren Standorten sind die Sand- und Silikat-Kiefernw{\"a}lder der Quarzsande und Sandstein-Verwitterungsb{\"o}den, deren Bodenvegetation durch Zwergstr{\"a}ucher, Moose und Strauchflechten gepr{\"a}gt ist. Hier siedelt die Kiefer in den Tieflagen besonders auf Binnend{\"u}nen und Sandern, aber auch auf K{\"u}stend{\"u}nen der Ostsee, in den Mittelgebirgen z. B. auf den Sandsteinriffen der S{\"a}chsischen Schweiz. Der dritte Wuchsbereich nat{\"u}rlicher Kiefernw{\"a}lder sind saure, n{\"a}hrstoffarme Moore, die ganz {\"u}berwiegend von Regenwasser gespeist werden. Auch die Kiefern-Moorw{\"a}lder sind in Nordostdeutschland und Bayern am h{\"a}ufigsten. Von diesen Standorten ausgehend, wo ihr Platz kaum von anderen Baumarten streitig gemacht wird, tritt die Waldkiefer immer wieder als Pionier auf weniger extremen Standorten auf. In der Naturlandschaft kam dies etwa nach Waldbr{\"a}nden oder St{\"u}rmen vor, doch der Mensch f{\"o}rderte die Kiefer durch Auflichtung der W{\"a}lder, Waldweide und Streunutzung stark. Auch die damit verbundene N{\"a}hrstoffverarmung macht eine exakte Abgrenzung nat{\"u}rlicher Kiefernstandorte unm{\"o}glich. Die schlechtw{\"u}chsigen und forstwirtschaftlich nicht interessanten, {\"a}sthetisch aber sehr ansprechenden nat{\"u}rlichen Kiefernbest{\"a}nde sind heute vor allem durch Stickstoff-Immissionen gef{\"a}hrdet. Trotz ihrer oft kargen Erscheinung besitzen sie einen hohen Wert f{\"u}r die Biodiversit{\"a}t und den Artenschutz. Neben bodenbewohnenden Flechten und regionalen Relikt-Endemiten ist vor allem die in den letzten Jahrzehnten zunehmend gef{\"a}hrdete Vielfalt an Mykorrhiza-Pilzen hervorzuheben, die der Kiefer das Leben auf extrem n{\"a}hrstoffarmen Standorten {\"u}berhaupt erm{\"o}glichen. Abschließend werden m{\"o}gliche Schutz- bzw. Regenerationsmaßnahmen wie das Abplaggen flechtenreicher Kiefernstandorte vorgestellt.}, language = {de} }