Papers by Klaus Katzensteiner
Alluvial forests in the temperate zone of Europe are frequently changing drastically in their hyd... more Alluvial forests in the temperate zone of Europe are frequently changing drastically in their hydrological regime, vegetation composition and structure, and disturbance dynamics. Causes are river regulations, historic land use, recent forest management, and introduced species such as Solidago canadensis agg. or the pathogenic fungus Hymenoscyphus fraxineus causing ash dieback. Climate change increases the scale of these changes. As a result, like in the present case study, pre-mature stands dominated by Pica abies or Fraxinus excelsior have to be clearcut. In order to achieve a tree species composition which is adapted to the altered site conditions and still economically desirable, tree planting in a larger scale is inevitable. To control competing vegetation (e.g., Solidago, Clematis, Rubus…), site preparation (mulching and tilling of planting strips) was deemed to be necessary but is discussed controversially. Effects of site preparation on indicators for soil functions were compared for the two dominating soil types, Fluvisols and Rendzic Leptosols, using a chronosequence approach. The following key results were obtained: (1) Soil type has a significant effect upon most indicators. (2) Areas treated ≥5 years ago have a significantly higher bulk density (and thus, despite partly decreased C-concentration, higher C-stocks) in the 20 cm topsoil indicating compaction. (3) Tilling strips significantly impact anecic earthworm abundance (+) compared to areas only mulched. (4) Effects of site preparation on organic C concentration (-), C/N-ratio (-), ratio of microbial to organic carbon (+), abundance of anecic earthworms (+) and hydraulic conductivity estimated from pedotransfer functions (-) were mainly significant for Rendzic Leptosols. This may reflect the mobilization of accumulated forest floor, which was present in mature spruce stands on Rendzic Leptosols but not on Fluvisols. (5) The ground vegetation shows an expected response to clearing (increased cover of light demanding species including Solidago canadensis agg.). Effects of site preparation could not be separated from clearing effects. (6) Nitrate concentrations in seepage are below drinking water standards and show no clear treatment effect, though highest values were found in declining spruce stands on Leptosols.
This report is a deliverable from the EU FP6 Integrated Project EFORWOODTools for Sustainability... more This report is a deliverable from the EU FP6 Integrated Project EFORWOODTools for Sustainability Impact Assessment of the Forestry-Wood Chain. The main objective of EFORWOOD was to develop a tool for Sustainability Impact Assessment (SIA) of Forestry-...
EGU General Assembly Conference Abstracts, Apr 1, 2009
Cambridge University Press eBooks, Dec 1, 2016
Journal of Applied Ecology, Mar 28, 2016
1. The ongoing changes to climate challenge the conservation of forest biodiversity. Yet, in ther... more 1. The ongoing changes to climate challenge the conservation of forest biodiversity. Yet, in thermally limited systems, such as temperate forests, not all species groups might be affected negatively. Furthermore, simultaneous changes in the disturbance regime have the potential to mitigate climate-related impacts on forest species. Here, we (i) investigated the potential long-term effect of climate change on biodiversity in a mountain forest landscape, (ii) assessed the effects of different disturbance frequencies, severities and sizes and (iii) identified biodiversity hotspots at the landscape scale to facilitate conservation management. 2. We employed the model iLand to dynamically simulate the tree vegetation on 13 865 ha of the Kalkalpen National Park in Austria over 1000 years, and investigated 36 unique combinations of different disturbance and climate scenarios. We used simulated changes in tree cover and composition as well as projected temperature and precipitation to predict changes in the diversity of Araneae, Carabidae, ground vegetation, Hemiptera, Hymenoptera, Mollusca, saproxylic beetles, Symphyta and Syrphidae, using empirical response functions. 3. Our findings revealed widely varying responses of biodiversity indicators to climate change. Five indicators showed overall negative effects, with Carabidae, saproxylic beetles and tree species diversity projected to decrease by more than 33%. Six indicators responded positively to climate change, with Hymenoptera, Mollusca and Syrphidae diversity projected to increase more than twofold. 4. Disturbances were generally beneficial for the studied indicators of biodiversity. Our results indicated that increasing disturbance frequency and severity have a positive effect on biodiversity, while increasing disturbance size has a moderately negative effect. Spatial hotspots of biodiversity were currently found in low-to mid-elevation areas of the mountainous study landscape, but shifted to higher-elevation zones under changing climate conditions. 5. Synthesis and applications. Our results highlight that intensifying disturbance regimes may alleviate some of the impacts of climate change on forest biodiversity. However, the projected shift in biodiversity hotspots is a challenge for static conservation areas. In this regard, overlapping hotspots under current and expected future conditions highlight priority areas for robust conservation management.
EGU General Assembly Conference Abstracts, Apr 1, 2019
EGUGA, Apr 1, 2018
Ungulate herbivores (e.g. red deer, chamois) play a crucial role in the establishment of tree reg... more Ungulate herbivores (e.g. red deer, chamois) play a crucial role in the establishment of tree regeneration after forest disturbance. This might affect the post-disturbance carbon dynamics of forest ecosystems. Information on the effects of ungulate herbivory on soil carbon processes after disturbance is, however, sparse. Since forest disturbances are expected to increase with changing climate, more studies are required to close this gap in knowledge. The present study investigates how soil respiration (Rs) and its autotrophic (Ra) and heterotrophic (Rh) components are affected by ungulate herbivores at two windthrown forest sites in the Northern Calcareous Alps, Austria. The sites were south exposed and differed with regard to the time since windthrow (9 and 13 years after disturbance). To study the effects of ungulate herbivory, measurement plots were established within fenced and non-fenced treatments at both sites. Tree regeneration at both windthrow sites was drastically reduced by ungulate herbivory. A re-establishing vegetation at non-fenced plots was dominated by herbs and grasses. The differences in vegetation were, however, less pronounced at the younger windthrow site. This was assumed to be the main reason that neither Rs, Ra, nor Rh showed a treatment effect. At the older windthrow site Rs and Rh were significantly (p < 0.05) lower at the fenced plots. The lower rates were mainly related to lower soil temperatures underneath the trees (crown shading). The results suggest that ungulate herbivory represents an important driver of post-disturbance soil carbon dynamics in the Northern Calcareous Alps.
Forest Ecology and Management, 2017
The effects of vitality fertilization on needle nutrient status and symptom development of Siroco... more The effects of vitality fertilization on needle nutrient status and symptom development of Sirococcus shoot blight (SSB) were examined in a long-term, single-tree fertilization experiment in a 90-yr old Norway spruce stand on acidic soil. Trees showing severe symptoms of SSB (''symptomatic trees", N = 72) and trees with less than 5% of the current-year shoots symptomatic of SBB (''asymptomatic trees", N = 72) were selected among the dominant and co-dominant trees within the stand and randomly assigned to three fertilization treatments: unfertilized control, dolomitic liming and gypsum & kieserite fertilization. Concentrations of macronutrients were determined in healthy current year needles of symptomatic and asymptomatic trees 3 and 6 years after fertilization and compared with the status in autumn prior to fertilizer treatment. Severity of SSB was rated yearly from 2001 to 2006 by estimating the percentage of affected current-year shoots in the crown in order to assess evolution of disease severity due to changes of nutritional status of the host. Both fertilizer treatments significantly increased foliar Ca and Mg concentrations, and as a result the primary differences in nutrient status between symptomatic and asymptomatic trees disappeared. Thus, vitality fertilization mitigated insufficient Ca and Mg supply that characterized symptomatic trees prior to fertilization, and balanced tree nutrition. Application of the water soluble Ca-and Mg-fertilizer (gypsum & kieserite-variant) induced a quick but only short-term fertilization effect whereas dolomitic liming resulted in significantly higher Ca and Mg concentrations compared to control 3 as well as 6 years after fertilization. In contrast, Ca-and Mg-deficiencies further intensified in the unfertilized trees. Balanced tree nutrition also mitigated disease severity of the fertilized trees and promoted tree recovery, indicating that the elements Ca and Mg are putatively involved in disease tolerance. Best results were achieved by fertilization with a water soluble Ca-and Mg-fertilizer which resulted in an 18.9% reduction of disease severity, assessed by the number of diseased shoots per tree, within five years. While dolomitic liming also promoted tree recovery (reduction in disease severity was 11.8%), in the unfertilized control variant a 3.5% increase was observed in the same period. Reduction in disease severity differed significantly from the control for both fertilizer treatments whereas differences between fertilizer treatments were not significant. Results of this study revealed that balanced nutritional status of mature Norway spruce due to vitality fertilization was associated to reduced symptom development of Sirococcus shoot blight.
European Journal of Forest Research, Dec 2, 2019
Ungulate herbivory can alter functional plant communities of early-successional forest ecosystems... more Ungulate herbivory can alter functional plant communities of early-successional forest ecosystems. The consequences of such vegetation changes on soil carbon cycling are still not fully understood. Here, we used an ungulate exclusion experiment to investigate how different levels of herbivory and associated changes in vegetation succession modulate soil CO 2 efflux and its heterotrophic and autotrophic sources following windthrow in temperate mountain forests. Our results indicate that only high levels of ungulate herbivory and associated vegetation shifts from tree to rather grass dominated plant communities affect soil CO 2 fluxes. We did not find evidence that a moderate herbivory level and accompanied smaller shifts in the functional plant community affect soil CO 2 fluxes. A greater soil CO 2 efflux under the influence of high herbivory pressure was primarily attributed to accelerated heterotrophic respiration, likely due to warmer soil conditions. Moreover, autotrophic respiration from grass roots and associated microbial communities is suggested to contribute to higher soil CO 2 fluxes. We conclude that intense herbivory and accompanied successional changes in the functional plant community enhance soil carbon losses following forest windthrow. This might have negative consequences for the soil carbon stocks and for the climate system.
EGUGA, Apr 1, 2012
ABSTRACT
Journal of natural history museum, Dec 17, 2015
The aim of this study was to assess the anthropogenic impacts on the vegetation structure and reg... more The aim of this study was to assess the anthropogenic impacts on the vegetation structure and regeneration of dominant tree species in the community managed mixed broadleaved forests of the Sargamatha (Everest) National Park buffer zone area. The forest plots were categorized into disturbed and semi-disturbed considering the scale of anthropogenic disturbances such as percentage of biomass extraction, lopping, tramping coverage and grazing intensity. For each forest type, three radii (10 m, 5 m and 2.5 m) plots were laid for sampling trees, sapling and seedling layers, respectively. In both the forest sites, Quercus semecarpifolia and Rhododendron arboreum were the main dominant tree species. The distribution of Q. semecarpifolia and R. arboreum along with diameter classes showed high stem density mainly concentrated in 2-15 cm diameter class. In both sites, the density of R. arboreum showed increment from sapling to seedling stage, while no seedling of Q. semecarpifolia was recorded in the disturbed site. The absence of Q. semecarpifolia seedlings in the disturbed forest sites could be associated with the practice of biomass removal and forest management activities. The study attributed that Rhododendron species in the study sites were not frequently cut, browsed, or lopped due to their religious belief and its ornamental value. Thus R. arboreum is expected to be slowly expanded if biotic pressure is maintained less. This may cause change in the vegetation structure and scarcity of resources for livelihood. On the whole, managing the forest in an equitable and sustainable way could satisfy basic needs and improve the livelihood of rural people in the study area.
Geoderma, Jul 1, 2020
Abstract The modelling of forest ecosystems is a broad scientific field, encompassing species dis... more Abstract The modelling of forest ecosystems is a broad scientific field, encompassing species distribution, dynamic forest succession, growth and disturbance, and biogeochemical cycles. Soil information is frequently required for a holistic and spatially explicit modelling approach. Information on soil properties at sufficient resolution to be incorporated in spatially distributed models is rare however, in particular for mountain forest areas that are poorly accessible and where the required sampling effort is high. In order to bridge this gap, we aim to develop a concept for predicting spatially continuous forest soil properties in mountain areas and substantiate it by comparing different statistical approaches to digital soil mapping, namely Random Forests and Generalized Additive Models. Therefore, we used field descriptions of 1653 legacy soil profiles from a forest area of 5130 km2 in Tyrol and modelled a variety of soil properties that are essential for the characterisation of forest sites with respect to tree growth. A set of 23 spatially explicit predictor variables, grouped according to geological substrate information, topography, climate, biotic variables, and time–space, were included in the concept and tested. There was a special focus on the predictive relevance of the newly developed geological substrate information, which includes lithogenetic units, lithological composition, and the multilayering of sediments. As a physical soil property, it was possible to predict the plant-available water storage capacity with a significant degree of accuracy, with r2 = 0.49–0.56, while for the biologically driven state variable organic humus layer thickness, r2 = 0.22–0.27 was achieved. For describing soil reaction, Ellenberg’s indicator value of vegetation turned out to be a suitable proxy for soil pH value, and was modelled with a high degree of predictive power with r2 = 0.75–0.77. All model results were verified by different evaluation methods, ranging from cross-validation to comparison with independent datasets, tests for spatial autocorrelation, and considering ecological soundness in variable selection. We were able to show that in addition to variables derived from Digital Terrain Models and climate information, the new type of detailed geological substrate information is the most relevant predictor and is promising for digital soil mapping in mountain areas. This finding was independent of the applied statistical approaches and both Generalized Additive Models and Random Forests showed comparable accuracy and proved to be appropriate for these tasks. In addition, we were able to support the modelling results by interpreting the predictors’ mode of action with regard to the underlying processes controlling soil properties.
Journal of Applied Entomology, Jan 12, 1994
ABSTRACT
International Journal of Remote Sensing, Oct 31, 2016
This study models landscape transformations and settlement dynamics in a highland area of Ethiopi... more This study models landscape transformations and settlement dynamics in a highland area of Ethiopia over a 56 year period (1957-2013). The analyses were performed using aerial photographs, satellite images, and field data. The remotely sensed images were geometrically and radiometrically corrected. Visual interpretation of aerial photographs and supervised classification of multispectral satellite images using the maximum likelihood algorithm were chosen for land-cover mapping. The population size was estimated by counting the houses on the aerial photographs and on the high-resolution images, and by direct census. The overall trend showed an increase of cropland and a decrease of other types of land cover. Landscape transformation rates recently slowed down due to ownership and policy restrictions. The average cropland holding size per family has decreased from 2.6 to 1.1 ha due to the exponential growth of the population. The relationship between settlement and cropland expansion is statistically significant. Models of logistic growth were fitted to the cropland area, and models of exponential and logistic growth to the population development to estimate the carrying capacity. The concomitant increase of population and the decrease of cropland per head resulted in a shortage of food and energy, highlighting the importance of policy decisions on land management.
Banko Janakari, 1970
The 'Community Forestry Program' has been considered successful in improving the environmental si... more The 'Community Forestry Program' has been considered successful in improving the environmental situation in the hills of Nepal by enhancing the vegetation coverage of degraded sites and by improving the supply of forest products to farmers. The restoration measures are considered sustainable if the ecosystems are self-supporting and resilient against perturbation. A community forest (CF) in the mid-hills of Nepal has been assessed for restoration success based on the comparison of vegetation structure and species diversity along a disturbance gradient, using a semi-protected natural forest as a reference site. In general, the community forest management (CFM) was able to re-establish forests on formerly severely degraded sites. Forest operations carried out during CFM have altered plant community composition, species richness and distribution, age class distribution of trees and vegetation structure. As a result, the CF was being transformed into a less diverse regular forest although the overall vascular plant diversity was retained with sufficient niches within the understorey vegetation.
Environmental Pollution, Oct 1, 2008
The dominant nitrogen (N) fluxes were simulated in a mountain forest ecosystem on dolomitic bedro... more The dominant nitrogen (N) fluxes were simulated in a mountain forest ecosystem on dolomitic bedrock in the Austrian Alps. Based on an existing small-scale climate model the simulation encompassed the present situation and a 50-yr projection. The investigated scenarios were current climate, current N deposition (SC1) and future climate (+2.5 degrees C and +10% annual precipitation) with three levels of N deposition (SC2, 3, 4). The microbially mediated N transformation, including the emission of nitrogen oxides, was calculated with PnET-N-DNDC. Soil hydrology was calculated with HYDRUS and was used to estimate the leaching of nitrate. The expected change of the forest ecosystem due to changes of the climate and the N availability was simulated with PICUS. The incentive for the project was the fact that forests on dolomitic limestone stock on shallow Rendzic Leptosols that are rich in soil organic matter are considered highly sensitive to the expected environmental changes. The simulation results showed a strong effect due to increased temperatures and to elevated levels of N deposition. The outflux of N, both as nitrate (6-25 kg N ha(-1)yr(-1)) and nitrogen oxides (1-2 kg N ha(-1)yr(-1)), from the forest ecosystem are expected to increase. Temperature exerts a stronger effect on the N(2)O emission than the increased rate of N deposition. The main part of the N emission will occur as N(2) (15 kg N ha(-1)yr(-1)). The total N loss is partially offset by increased rates of N uptake in the biomass due to an increase in forest productivity.
European Journal of Forest Research, Nov 13, 2014
Changing natural disturbance regimes threaten forest functions in the Northern Calcareous Alps, w... more Changing natural disturbance regimes threaten forest functions in the Northern Calcareous Alps, with steep, sun-exposed sites on shallow soils at particular risk due to inhibited recovery. Natural tree regeneration after severe disturbances may fail due to extreme microclimate, dense layers of competing understorey vegetation and herbivory. In order to gain insight into regeneration patterns and dynamics, chronosequences of disturbed forest sites were selected along a longitudinal section of the Austrian Northern Calcareous Alps. Regeneration densities of trees, cover of competing vegetation and microsite characteristics were recorded on a total of 19 disturbed sites and in the respective adjacent forest stands. Although high densities of germinants and small seedlings (B0.1 m) were recorded in the forest stands, recruitment establishment (trees [0.1 m) frequently failed on both disturbed sites and adjacent stands. In fact, half of the disturbed sites were found to be without sufficient regeneration and no significant increase of regeneration density was detected with time since disturbance. Overall, regeneration densities reflect a very critical situation along the disturbance chronosequence. Even if seedling banks are composed of individuals smaller than 0.1 m, seedling mortality is high. General linear mixed models revealed positive effects of convex microsites and thick organic layers on Picea abies (L.) Karst. establishment, while dense litter and grass cover impaired spruce regeneration. Regeneration of other tree species was scarce. The results corroborate the urgent need for establishing seedling banks of larger individuals ([0.1 m) and for reducing ungulate browsing. They also underline the need for comprehensive long-term studies to better understand the dynamic processes, driving resilience of disturbed sites.
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Papers by Klaus Katzensteiner
It was the fruit of many meetings and of a final workshop in Paris, INRA.
In Europe an abundance of humus taxonomies exists starting with early approaches in the late 19th century. Frequently used in an international context, they do not cover all site conditions in the European area. Although having basic concepts and general lines, the European (and North American, Canadian) classification systems differ in important parameters used for the description and classification of humus forms. These discrepancies result in incongruities, so they require adjustments when exchanging partially compatible soil data, even between nearby countries. In 2003, 26 European specialists in humus forms met in Trento (Italy) and decided to formulate rules of classification based on morphogenetic descriptions and diagnostic horizons, adapted to European ecological conditions. Taking into account old and new European and North American systems of humus forms classification, six main references (Anmoor, Mull, Moder, Mor, Amphi and Tangel) were defined, each of them further divided into more detailed categories. This inventory assigned a strong discriminatory power to the action of soil animals. Both semiterrestrial (anoxic) and terrestrial (aerated) topsoils were classified. Descriptors of diagnostic horizons were conceived in accordance with recent international soil classifications. Assigning an 'ecological value' to each main humus form along a gradient from biologically active forms, degrading and incorporating all organic remains, to those characterized by the accumulation of poorly transformed organic matter, this European system of classification avoids a strong hierarchical structure and allows a flexible approach open to additional ecological contributions and renditions.