Andreas Rothe

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Papers by Andreas Rothe

Old World megadroughts and pluvials during the Common Era

Science advances, 2015

Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fen... more Climate model projections suggest widespread drying in the Mediterranean Basin and wetting in Fennoscandia in the coming decades largely as a consequence of greenhouse gas forcing of climate. To place these and other "Old World" climate projections into historical perspective based on more complete estimates of natural hydroclimatic variability, we have developed the "Old World Drought Atlas" (OWDA), a set of year-to-year maps of tree-ring reconstructed summer wetness and dryness over Europe and the Mediterranean Basin during the Common Era. The OWDA matches historical accounts of severe drought and wetness with a spatial completeness not previously available. In addition, megadroughts reconstructed over north-central Europe in the 11th and mid-15th centuries reinforce other evidence from North America and Asia that droughts were more severe, extensive, and prolonged over Northern Hemisphere land areas before the 20th century, with an inadequate understanding of ...

Is continuous-cover silviculture, as practised in Bavaria, suitable for use in wet eucalypt forests in Tasmania, Australia?

Australian Forestry, 2015

Appropriate silviculture, based on natural forest dynamics and ecological attributes of tree spec... more Appropriate silviculture, based on natural forest dynamics and ecological attributes of tree species, is fundamental to the sustainable management of native (natural and semi-natural) forests for wood production. Continuous-cover silviculture works well in shade-tolerant spruce-fir-beech forests of Central Europe and can be regarded as "close-to-nature" silviculture, particularly where there is a focus on maintaining some old-growth elements for long-term retention. Continuous-cover silviculture, however, cannot be regarded as "close-to-nature" for Australian wet eucalypt forests, which are dominated by shade-intolerant eucalypts that are dependent on intensive disturbance, usually associated with fires, for their regeneration.

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Médecine de précision et cancer; Precision medicine and cancer

Uniform climate sensitivity in tree-ring stable isotopes across species and sites in a mid-latitude temperate forest

Tree physiology, 2015

Tree-ring stable isotopes, providing insight into drought-induced eco-physiological mechanisms, a... more Tree-ring stable isotopes, providing insight into drought-induced eco-physiological mechanisms, are frequently used to reconstruct past changes in growing season temperature and precipitation. Their climatic response is, however, still not fully understood, particularly for data originating from non-extreme, mid-latitude environments with differing ecological conditions. Here, we assess the response of δ(13)C, δ(18)O and tree-ring width (TRW) from a temperate mountain forest in the Austrian pre-Alps to climate and specific drought events. Variations in stem growth and isotopic composition of Norway spruce, common beech and European larch from dry, medium and moist sites are compared with records of sunshine, temperature, moisture, precipitation and cloud cover. Results indicate uniform year-to-year variations in δ(13)C and δ(18)O across sites and species, but distinct differences in TRW according to habitat and species. While the climate sensitivity of TRW is overall weak, the δ(13)...

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Zur Baumarteneignung bei Klimawandel: Ableitung der Trockenstress-Anfälligkeit wichtiger Waldbaumarten aus Jahrringbreiten

ABSTRACT The predicted increase in frequency and intensity of climatic extremes, like drought epi... more ABSTRACT The predicted increase in frequency and intensity of climatic extremes, like drought episodes, imposes a challenge on the choice of commercial forest trees under climate change conditions. The present study aims at quantifying the impact of summer drought on growth of spruce, pine, silver fir, beech and oak as the main forest tree species in Southern Germany, and includes Douglas fir as a possible alternative for spruce. Series of tree-ring widths from more than 1400 trees from 48 sites all over Bavaria and adjacent states are employed for growth/climate modeling and pointer year analysis to derive predications about the climatic limitation of tree growth subject to species, regional climate and site quality. Response functions relating tree growth to climatic variables in monthly resolution have been applied. The obtained parameters were subject to principal component analysis to derive a more condensed representation of climatic constraints on tree growth. Soil water balance modeling was applied to refine the connections between regional climate and growth reactions to drought in terms of site quality. A modification of Brook90 (Brook90-LWF) has been used employed for water balance modeling. Pointer years were choosen a priori according to documented drought years and used to calculate short- and long-term impact of drought on tree-growth. For all species under investigation, critical areas for tree growth could be identified. Generally, the warmer and drier northern part of the investigation area is more unfavorable, with spruce generally being more affected than other species in terms of short- and long-term impact of summer drought on tree-growth (Figure 1). Furthermore, in a condensed view of dendroclimatic forcings, spruce depicts the strongest connection to the aspect “summer drought” throughout the investigation area, whereas oak shows the weakest connection (Figure 5). As a main result, oak is superior to all other species under investigation regarding drought tolerance throughout the investigation area. But also silver fir could replace the most critical spruce on a wide range of sites. Furthermore, the surprisingly high variability in reaction to drought observed on regional and stand level (Figure 3) implies a high adaptive potential of the populations within the possibilities of their inherent genetic diversity, hampering the derivation of clear climatic or site-related thresholds (compare Figure 2).

Evaluating the species-and site-specific differences in the physiological response of Picea abies, Fagus sylvatica and Larix decidua to drought

ABSTRACT Sensitive regions like the Alps are very vulnerable to climate change. Especially warmer... more ABSTRACT Sensitive regions like the Alps are very vulnerable to climate change. Especially warmer temperatures and a higher frequency of drought periods may imply strong effects on mountain ecosystems. In the Northern Limestone Alps, temperatures were already 1 °C higher (compared to the reference period 1941-1970) in the last two decades. Within a Bavarian-Austrian EU-project (INTERREG program) we investigated long-term growth patterns of mountain tree species and a possible growth effect caused by climate change using a dendroecological approach. In total we measured the ring widths of ~1300 living, on average 180 year old trees. The samples were taken along altitudinal gradients, ranging from 500 up to 1700 m a.s.l., in five different regions in the Northern Austrian and Bavarian Limestone Alps, covering the most prevalent coniferous (Picea abies, Abies alba, Larix decidua, Pinus sylvestris) and broad-leafed (Fagus sylvatica, Acer pseudoplatanus) mountain forest species. To get more detailed information about the physiological response to climate and especially drought events of different tree species, an additional study was conducted in the Kalkalpen Nationalpark, Austria. Stable isotopes (δ13C and δ18O) of Picea abies, Fagus sylvatica and Larix decidua tree-rings (8 trees per species and site) were analysed at three different sites. The sites are located at the montane elevation level (900 m a.s.l.) on a south-facing and a north-facing slope as well on a plateau situation with deeper soils. Our main focus deals with the following questions: i) Is it possible to identify &quot;drought events&quot; in a region like the Alps with generally humid precipitation conditions (1400 mm/a), by analysing stable isotopes in tree rings? ii) Are there species- and/or site-specific differences in the isotopic signatures - also with respect to the trees&#39; climate response? We will present (i) the isotopic signatures for the common period 1970-2010, (ii) their response to climate conditions, and (iii) compare them with our findings of the comprehensive tree-ring width measurements.

Patterns of drought tolerance in major European temperate forest trees: climatic drivers and levels of variability

Global Change Biology, 2014

The future performance of native tree species under climate change conditions is frequently discu... more The future performance of native tree species under climate change conditions is frequently discussed, since increasingly severe and more frequent drought events are expected to become a major risk for forest ecosystems. To improve our understanding of the drought tolerance of the three common European temperate forest tree species Norway spruce, silver fir and common beech, we tested the influence of climate and tree-specific traits on the inter-and intra-site variability in drought responses of these species. Basal area increment data from a large tree-ring network in Southern Germany and Alpine Austria along a climatic cline from warm-dry to cool-wet conditions were used to calculate indices of tolerance to drought events and their variability at the level of individual trees and populations.

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Changes in soil structure caused by the installation of time domain reflectometry probes and their influence on the measurement of soil moisture

Water Resources Research, 1997

The time domain reflectometry technique for measuring the volumetric soil water content is highly... more The time domain reflectometry technique for measuring the volumetric soil water content is highly sensitive to installation effects because the sampling volume is more heavily weighted close to the transmission line elements. To investigate changes in soil structure caused by the installation and its influence on the measurement, field and laboratory experiments covering different probe dimensions, soil types, and installation techniques were performed. The results indicate that merely pushing the probes into the soil entails a significant reduction of the measured water content up to 0.10 cm3/cm3. The effect is strongest close to saturation since the large pores are affected most. The degree of compression differed strongly according to the varying compressibility of the investigated soils. It was smaller for the smaller probe indicating a more favorable relationship between sampling volume and compression. The compression effect could be minimized using a drill to remove the soil for the probes. X ray-computed tomography was used to visualize the installation effects and to measure the density distribution around the probes.

Mountain forest growth response to climate change in the Northern Limestone Alps

Trees, 2014

Key message Growth response to climate differs between species and elevation. Fir is the most dro... more Key message Growth response to climate differs between species and elevation. Fir is the most droughttolerant species. The mountain forests are robust to the climatic changes until now. Abstract Alpine mountain forests provide a wide range of ecological and socio-economic services. Climate change is predicted to challenge these forests, but there are still considerable uncertainties how these ecosystems will be affected. Here, we present a multispecies treering network of 500 trees from the Berchtesgaden Alps (Northern Limestone Alps, Southeast Germany) in order to assess the performance of native mountain forest species under climate change conditions. The dataset comprises 180 spruce, 90 fir, 110 larch and 120 beech trees from different elevations and slope exposures. We analyse the species with respect to: (1) the general growth/climate response; (2) the growth reaction (GR) during the hot summer in 2003 and (3) the growth change (GC) resulting from increasing temperatures since the 1990s. Spruce is identified as the most drought-sensitive species at the lower elevations. Fir shows a high drought tolerance and is well suited with regard to climate change. Larch shows no clear pattern, and beech remains unaffected at lower elevations. The unprecedented temperature increase of the last decades did not induce any distinct GC. The mountain forests of the Berchtesgaden Alps appear to be robust within the climatic changes until now.

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Size-dependent responses to summer drought in Scots pine, Norway spruce and common oak

Trees, 2012

In this study, we provide a detailed analysis of tree growth and water status in relation to clim... more In this study, we provide a detailed analysis of tree growth and water status in relation to climate of three major species of forest trees in lower regions of Bavaria, Southern Germany: Scots pine (Pinus sylvestris), Norway spruce (Picea abies) and common oak (Quercus robur). Tree-ring chronologies and latewood d 13 C were used to derive measures for drought reaction across trees of different dimensions: growth reduction associated with drought years, long-term growth/climate relations and stomatal control on photosynthesis. For Scots pine, growth/ climate relations indicated a stronger limitation of radial growth by high summer temperatures and low summer precipitation in smaller trees in contrast to larger trees. This is corroborated by a stronger stomatal control on photosynthesis for smaller pine trees under average conditions. In dry years, however, larger pine trees exhibited stronger growth reductions. For Norway spruce, a significantly stronger correlation of tree-ring width with summer temperatures and summer precipitation was found for larger trees. Additionally, for Norway spruce there is evidence for a change in competition mode from size-asymmetric competition under conditions with sufficient soil water supply to a more size-symmetric competition under dry conditions. Smaller oak trees showed a weaker stomatal control on photosynthesis under both dry and average conditions, which is also reflected by a significantly faster recovery of tree-ring growth after extreme drought events in smaller oak trees. The observed patterns are discussed in the context of the limitation-caused matter partitioning hypothesis and possible species-specific ontogenetic modifications.

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Soil Carbon and Nitrogen Changes Under Douglas-fir With and Without Red Alder

Soil Science Society of America Journal, 2002

based on plantations with replicated, randomized plots, and it cannot be excluded that a priori s... more

Response of artificial acid irrigation, liming, and N-fertilisation on elemental concentrations in needles, litter fluxes, volume increment, and crown transparency of a N saturated Norway spruce stand

by Andreas Rothe and Christian Huber

Forest Ecology and Management, 2004

The response of N-fertilisation, irrigation, acid irrigation, and liming on concentrations of ele... more The response of N-fertilisation, irrigation, acid irrigation, and liming on concentrations of elements in needles, fluxes of elements in litter, volume increment, and crown density on a full stocked, healthy, and vigorously growing mature spruce stand was investigated. The plots of the Höglwald site in Southern Bavaria exhibited a high volume increment with regularly more than 20 m 3 ha À1 per year, despite the high age of the stand (77 years at the beginning of the experiment in 1984). Neither a distinct growth reduction of the stand due to acid irrigation, or N oversaturation, nor an enhancement of growth due to N-fertilisation, irrigation, or liming of the stand could be detected. For the years 1984 and 1985 a marked decrease in crown density was detected for all plots. This was followed by a stagnation for 2 years. Afterwards the crown density improved until the end of the investigation for all plots. Neither acid irrigation, nor liming altered the amount of litter fall. Ca fluxes in litter, and concentrations in needles were enhanced on most of the limed plots five to six years after liming. Acid irrigation reduced Ca content in litter, but other elements were not or only slightly influenced. The nutritional status of all plots as shown by the concentrations of elements in needles indicates that for most of the years a sufficient to high supply of N, P, Ca, and Mg for all investigated plots, whereas K concentration in needles exhibited wide year to year variations. Most of the elemental concentrations in needles and fluxes in litter were not influenced by any of the treatments. Also, N-fertilisation did not enhance the N concentrations in needles significantly. #

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Modeling the effects of acid deposition on the biogeochemistry of the Hoeglwald spruce stand, FRG

Forest Ecology and Management, 1998

ABSTRACT The intensively monitored Hoeglwald spruce site in southern Bavaria, Germany is located ... more ABSTRACT The intensively monitored Hoeglwald spruce site in southern Bavaria, Germany is located in a region with high atmospheric inputs of acidifying substances. In order to interpret the experimental data and to perform model validation, the biogeochemical model SAFE was parameterized for the site. SAFE is a dynamic, multilayer model that includes chemical weathering, cation exchange and soil solution equilibria. Reconstructed historic deposition and nutrient uptake and cycling patterns were made. To predict the general chemical characteristics of the upper part of the soil profile it was necessary to introduce two important elements in the parameterization of the model, gaseous uptake of nitrogen, and to assign a base cation uptake distribution different from fine root distribution. The model predicted the general characteristics of soil solution chemistry. Soil solution pH was well predicted for the mineral soil, but underpredicted for the O layer, due to the model assumption that nitrification is complete. The model could not reproduce high fluxes of SO42−, All and acidity in the A layer, while modeled base cation fluxes agree with data, since SAFE does not include SO42− dynamics that could explain the mobilization in the A layer, or immobilization in the AB layer. Fluxes and concentrations of SO42−, NO3−, Al and base cations at the 40 cm level (AB horizon) were all well reproduced by the model. The modeled decreasing trends in base cation concentrations are opposite to the increase shown by the data. The model clearly shows the importance of nutrient cycling for the soil chemistry in rooting zone. The SAFE model suggests that the Hoeglwald spruce stand has been subject to severe acidification due to acid inputs, and that the Hoeglwald spruce stand is showing signs of recovery from acidification. At present, model uncertainties may be too large to draw definite conclusions regarding recovery rate.

A comparison of sites in the EXMAN project, with respect to atmospheric deposition and the chemical composition of the soil solution and foliage

Forest Ecology and Management, 1994

... project, with respect to atmospheric deposition and the chemical composition of the soil solu... more

Elevation-specific tree-ring chronologies of Norway spruce and Silver fir in Southern Germany

Dendrochronologia, 2012

Tree-ring (TR) chronologies are important instruments for the dating and provenance analyses of h... more Tree-ring (TR) chronologies are important instruments for the dating and provenance analyses of historical wood, as well as for climate reconstructions. However, radial growth patterns differ between tree species and growing environments. Therefore chronologies are more or less specific for a certain tree species, region and elevation. Chronologies that are restricted to more confined regions could extend the possibilities for dating, dendroprovenancing and regional climate reconstructions.

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Vulnerability of Norway spruce to climate change in mountain forests of the European Alps

Climate Research, 2014

Mountain forests offer a range of socio-economic and ecological services, e.g. providing wood har... more Mountain forests offer a range of socio-economic and ecological services, e.g. providing wood harvest products, serving as hotspots of biodiversity and fulfilling protective functions. In the European Alps, where these environments are dominated by drought-sensitive Norway spruce, it has been questioned whether these services can be secured in the substantially warmer and drier climates predicted for the mid-to-late 21st century. Here, we compile a tree-ring width network of 500 spruce trees from the Northern Limestone Alps to assess growth reactions to drought events and evaluate the long-term impact of the recent temperature shift through analyses along elevational transects. Our dataset covers a larger region in the Northern European Alps extending 250 km from west to east and encompassing an altitudinal range of 1200 m (from 500 to 1700 m a.s.l.). Climate-growth analyses reveal spatially varying drought sensitivities within this spruce network, with elevation (along with associated hydrothermal changes) being the key drivers behind the varying responses. Trees at lower elevations are affected negatively by drought and high temperatures, but at higher altitudes, spruce benefits from warmer climatic conditions. However, despite a sharp temperature increase of ~1°C since the 1990s, we observed neither growth suppression at the lower elevation sites nor growth increase at higher elevation sites. These findings reveal the ability of mountain forests to adapt to an unprecedented temperature shift, suggesting that adaptation to forthcoming climate changes might not require a shift in tree species composition in the Northern Limestone Alps.

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Nutritional interactions in mixed species forests: a synthesis

Canadian Journal of Forest Research, 2001

For more than a century, scientists have considered whether mixtures of tree species may differ i... more For more than a century, scientists have considered whether mixtures of tree species may differ in nutrition and yield relative to monocultures. We review the empirical evidence on the nutritional interactions of tree species in mixtures, including information on foliar nutrition, soil nutrient supply, rates of nutrient input, and patterns of root distribution. Linear effects were most common, with mixtures intermediate in value between monocultures. In some cases, values for mixtures were lower than expected, indicating an antagonistic interaction. A few cases that included nitrogenfixing species showed a synergistic interaction, with mixtures showing higher values than monocultures. Nutrient concentrations in foliage of Sitka spruce (Picea sitchensis (Bong.) Carrière) were improved in mixtures with other conifers in three studies, in contrast to four studies with mixtures of various conifers and hardwoods that showed no effect of mixtures on foliage nutrient concentrations. Mixtures that combine species with and without the ability to fix atmospheric nitrogen have shown a full range of foliar responses from decreases to increases in phosphorus, to increases in nitrogen, to no effect of mixtures. Rates of litter decomposition usually showed no effect of species mixtures, but a few cases demonstrated both increases and decreases in decomposition relative to monocultures. Pools of soil nutrients generally did not differ between mixtures and monocultures. Root distributions in mixtures of Norway spruce (Picea abies (L.) Karst.) and beech (Fagus sylvatica L.) were altered in mixtures; compared with monocultures, spruce rooted more shallowly in mixtures with beech, and beech rooted more deeply in mixtures with spruce. General conclusions are limited by the small number of studies that directly addressed mixed-species effects in forests, and the wide variety of observed interactions. Further research would be particularly helpful in identifying situations where nonlinear interactions may develop, including the species and site conditions that promote nonlinear interactions. Neighborhood methods, which analyze the relationship between stand composition and nutritional properties on a small spatial scale, offer great potential for exploring nutritional effects in mixed-species stands.

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Influence of tree species composition on soil and soil solution properties in two mixed spruce-beech stands with contrasting history in Southern Germany

Plant and soil, 2002

The properties of the soil and soil solution of two mixed spruce-beech forests in Southern German... more The properties of the soil and soil solution of two mixed spruce-beech forests in Southern Germany were investigated in order to identify non-additive effects of tree species compared to the monocultures. At five subplots in each of the two monocultures and at 10 subplots in each of the two mixed stands humus morphology, topsoil acidity as well as nitrate and sulphate concentrations in seepage water below the rooting zone were measured. At the Höglwald site, an 8×8 m sampling grid was also installed. Tree species composition within a 10 m circle surrounding each sampling point was correlated with the soil properties and the soil solution properties using the method of breakpoint estimation as well as a linear and a cubic model. At both sites, thickness and acidity of the forest floor as well as sulphate and nitrate concentrations in seepage water were significantly higher in the spruce monocultures than in the beech monocultures. Non-linear patterns in the correlation between both the thickness and the acidity of the forest floor and tree species composition occurred at both sites. In addition, nitrate concentration in the seepage water showed a non-linear correlation pattern at the Höglwald site. The correlation patterns were site specific and depended on stand history. While the influence of spruce at the Höglwald site was greater than expected from spruce monocultures, the opposite was found at the Schongau site. Interaction effects on nitrate concentration were absent at the Schongau site. Interaction effects on sulphate concentrations were absent at both sites. Current knowledge about the complex processes and patterns in mixed species stands is still limited. At least for certain properties, mixed species stands cannot be treated as a summation of the corresponding monocultures.

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Estimating forest biomass supply from private forest owners: A case study from Southern Germany

Biomass and Bioenergy, 2012

ABSTRACT In this article we developed a method to estimate forest biomass availability in a situa... more ABSTRACT In this article we developed a method to estimate forest biomass availability in a situation with small-scale privately owned forests and applied it to three administrative districts in Southern Germany where the majority of owners is organised in forest owners associations. Based on gross annual increment of regional forest resources we calculated a theoretical potential of above-ground biomass from which we subtracted technical and ecological constraints, e.g. restrictions resulting from conservation needs or nutrient removal. The resulting figure was the bio-technical potential of forest biomass. We then assessed the socio-economic potential of forest biomass by considering recent timber felling rates and log grading of owners. In order to determine market potential we differentiated between self-consumption and marketed timber. We compared the calculated potential and timber utilisation patterns of forest owners, deriving the additional supply potential of forest biomass. Most of the data were obtained by a stratified random interview of 226 private forest owners organised in forest owners associations. Although observed harvest intensity was high there was still a considerable potential for increased use of forest biomass. However, willingness of owners to intensify timber harvesting and to supply fuel wood on the basis of long-term contracts is a restriction to additional mobilisation of wood.

Impact of several common tree species of European temperate forests on soil fertility

Annals of Forest Science, 2002

The aim of the present work was to provide a synopsis of the scientific literature concerning the... more The aim of the present work was to provide a synopsis of the scientific literature concerning the effects of different tree species on soil and to quantify the effect of common European temperate forest species on soil fertility. The scientific literature dealing with the tree species effect on soil has been reviewed. The composition of forest overstory has an impact on the chemical, physical and biological characteristics of soil. This impact was highest in the topsoil. Different tree species had significantly different effects on water balance and microclimate. The physical characteristics of soils also were modified depending on the overstory species, probably through modifications of the soil fauna. The rates of organic matter mineralization and nitrification seem to be dependent on tree species. A coniferous species, Picea abies, had negative input-output budgets for some nutrients, such as Ca and Mg. This species promoted a higher soil acidification and a decrease in pH. Thus, it should not be planted in very poor soils in areas affected by acidic atmospheric depositions. Nevertheless, the effect of the canopy species on soil fertility was rarely significant enough to promote forest decline. The impact of a tree species on soil fertility varied depending on the type of bedrock, climate and forest management.

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