H. Hasenauer - Academia.edu (original) (raw)
Papers by H. Hasenauer
Annals of Forest Science, 2016
Daily weather data are an important constraint for diverse applications in ecosystem research. In... more Daily weather data are an important constraint for diverse applications in ecosystem research. In particular, temperature and precipitation are the main drivers for forest ecosystem productivity. Mechanistic modeling theory heavily relies on daily values for minimum and maximum temperatures, precipitation, incident solar radiation and vapor pressure. These data are usually provided by interpolation techniques using measured values from surrounding stations
Ozone is one of the most important damaging air pollutants for forests in Austria. The mean atmos... more Ozone is one of the most important damaging air pollutants for forests in Austria. The mean atmospheric ozone concentration varies between 22.5 and 51.5 ppb (parts per billion) depending on altitude. Based on the emissions of the precursor substances (nitrous oxides and volatile hydrocarbons), the concentrations increase around 0.2 ppb per year and exceed the threshold for effects on plants.
GAIA - Ecological Perspectives for Science and Society, 2014
FarmClim aims at contributing to a more considerate use of nitrogen in Austrian agriculture. The ... more FarmClim aims at contributing to a more considerate use of nitrogen in Austrian agriculture. The transdisciplinary research project attempts to tackle the “science-policy gap” by using a participatory approach, that is, stakeholders influence the research process as much as the scientists strive for the implementation of their ideas. This paper describes the project design and communication processes. Full integration of practice partners adds to the complexity of the project's structure, but brings consider able benefits right from the outset. Taking advantage of the existing institutional setting of FarmClim partners, we expect to maintain expert consultancy beyond the lifetime of the project, helping agriculture to meet the challenges of environmental and economic performance of a producing agriculture.
Sustainable Forest Management
ABSTRACT The aim of this chapter is to review different approaches for simulating forest developm... more ABSTRACT The aim of this chapter is to review different approaches for simulating forest development in regeneration modeling. The features, shortcomings, further needs and trends of regeneration modeling are presented and discussed in the context of mechanistic, gap, statistical and nonparametric forest models. The data requirements are also described. Special emphasis is put on supplying information for modelers applying individual-tree models in uneven-aged stands.
Forest Ecology and Management, 2012
Large scale forest productivity estimates are of increasing interest as more demands are made on ... more Large scale forest productivity estimates are of increasing interest as more demands are made on forest resources. In principle three different methods are currently available: (i) forest growth data from forest research plots and/or forest inventory sampling points based on repeated tree observations, (ii) flux tower observations which record the gas exchange of the plant atmosphere interactions for a given vegetation type, and (iii) remotely sensed data for a continuous cover of net primary productivity estimates. In this paper we focus on the conceptual challenge in comparing ''space based'' moderate resolution imaging spectroradiometer (MODIS) satellite driven net primary production (NPP) vs. terrestrial ''ground based'' productivity estimates using forest increment data from 151 long term research plots with a well documented management history. The Austrian biomass functions are applied to derive ground based NPP estimates based on repeated tree observations from the plots. In addition we use BIOME-BGC as a diagnostic tool for exploring conceptual constraints among the two methods. The results of the study can be summarized as follows: (i) MODIS satellite driven annual NPP estimates provide a continuous productivity estimate across Austria and no significant differences between different daily climate input data sets were evident. (ii) MODIS NPP predictions provide forest productivity estimates of fully stocked forests with a complete crown cover. This is confirmed by the results of spin-up runs of the BIOME-BGC model. (iii) Terrestrial driven NPP predictions using the Austrian biomass functions compared well with MODIS driven estimates after addressing stand density effects of the forest plot data. The influence of stand density were known to be an integral component in reconciling ''space based'' satellite vs. ''ground based'' derived forest productivity estimates. After addressing stand density, computed forest productivity estimates compared well with MODIS-based estimates. This suggests that combining both methods will enhance our ability to generate forest productivity assessments across large forest areas.
Forest Ecology and Management, 2007
Large-scale ecosystem models are designed to reproduce and quantify ecosystem processes. Based on... more Large-scale ecosystem models are designed to reproduce and quantify ecosystem processes. Based on plant functions or species-specific parameter sets, the energy, carbon, nitrogen and water cycles of different ecosystems are assessed. These models have been proven to be important tools to investigate ecosystem fluxes as they are derived by plant, site and environmental factors. The general model approach assumes uniform and fully stocked forests but since most European forests are managed (e.g., thinned) it is essential to understand the limits and precision of such models when applied to managed forest ecosystems. The purpose of this study is to investigate and incorporate common forest management practices within the large-scale ecosystem model Biome-BGC. Using ''Monte-Carlo'' simulations we analyze the theoretical response to current model settings assuming steadily decreasing changes in stand density. Results of the MC simulations as well as the comparison with measured data suggest that the resulting predictions will be biased. Using long-term experimental plots of Norway spruce (Picea abies L. Karst.) and common beech (Fagus sylvatica L.) forests with a well-documented thinning history, we propose a thinning subroutine, which addresses the changes in allocation patterns after stand density changes. Validation tests of improved model structure across different long-term experimental sites in Central Europe revealed unbiased and consistent simulation results.
Remote Sensing, 2016
Net primary production (NPP) is an important ecological metric for studying forest ecosystems and... more Net primary production (NPP) is an important ecological metric for studying forest ecosystems and their carbon sequestration, for assessing the potential supply of food or timber and quantifying the impacts of climate change on ecosystems. The global MODIS NPP dataset using the MOD17 algorithm provides valuable information for monitoring NPP at 1-km resolution. Since coarse-resolution global climate data are used, the global dataset may contain uncertainties for Europe. We used a 1-km daily gridded European climate data set with the MOD17 algorithm to create the regional NPP dataset MODIS EURO. For evaluation of this new dataset, we compare MODIS EURO with terrestrial driven NPP from analyzing and harmonizing forest inventory data (NFI) from 196,434 plots in 12 European countries as well as the global MODIS NPP dataset for the years 2000 to 2012. Comparing these three NPP datasets, we found that the global MODIS NPP dataset differs from NFI NPP by 26%, while MODIS EURO only differs by 7%. MODIS EURO also agrees with NFI NPP across scales (from continental, regional to country) and gradients (elevation, location, tree age, dominant species, etc.). The agreement is particularly good for elevation, dominant
Forstwissenschaftliches Centralblatt, 2002
The present paper documents the practical applicability of growth simulators, gives an overview o... more The present paper documents the practical applicability of growth simulators, gives an overview of current model approaches, defines standards for the description and evaluation of growth models and growth simulators and indicates research needs. The recommendations aim to give users of growth simulators confidence in the transition to modern prediction systems and to increase the level of acceptance of new information technologies. The recommendations provide developers with guidelines for model description, model evaluation and software development and thus contribute towards efficient cooperation .
There is an increasing demand to include biodiversity assessments as an additional management inp... more There is an increasing demand to include biodiversity assessments as an additional management input within silvicultural decision making. A number of forest models are in use to support forest management planning. However, none of these models was explicitly designed to consider the biodiversity of forest ecosystems and how this may change under different silvicultural treatments. In this paper prominent attributes and measures of biodiversity and the data requirements for their calculation are identified based on a review of the literature. Existing forest models are classified with respect to the general modeling approach (i.e. empirical vs. process-based models), structural attributes and phenomena considered. After comparing the required data for biodiversity assessments and the available output of forest model types, we discuss to what extent existing models can satisfy the information needs for biodiversity assessments at the stand level. The main conclusion is that an extensi...
Forest Ecology and Management, 2005
The impacts that stand treatments have on carbon, nitrogen and water cycles is a key question rel... more The impacts that stand treatments have on carbon, nitrogen and water cycles is a key question relating the sustainability of forests to individual forest management decisions. While the response of the above ground carbon cycle may be relatively easy to measure and is well understood, e.g. volume growth response due to thinning, the impact of stand treatment and different harvesting scenarios on the water, and nutritional status of the remaining trees and site as well as on the below ground carbon and nitrogen cycle is much more difficult to assess due to the difficulty of obtaining reliable data. An alternative that eliminates the need for detailed site-specific data is to use existing models that were explicitly designed for studying biogeochemical processes. In this paper we test and evaluate the applicability of a species-specific mechanistic biogeochemical model to assess the impact of different harvesting scenarios after thinning. Data are available from 36 Norway spruce stands covering three regions each with three harvesting scenarios after thinning and four replications. The different harvesting scenarios applied are: (1) whole tree harvest, (2) whole tree harvest after one vegetation period, i.e. without needles, and (3) commercial stem wood harvest. The modeling results suggest that the variant 3 exhibited the highest growth efficiency, a measure of net carbon uptake or growth, versus all other harvesting methods. This is confirmed by the available field observations. Nitrogen, an indicator of nutrient supply, behaved similarly. The important exception was nitrogen plant uptake, which was lower immediately after thinning on the sites where the lowest amount of biomass was removed. Significant relationships exist between observed versus modeled stand volume and volume growth suggesting that mechanistic modeling is a suitable diagnostic tool for analyzing the impacts of different management practices and thus, such models can be efficiently used to enhance silvicultural decision-making.
Forest Ecology and Management, 1999
Using 30 years of climate records from 20 weather stations, we investigate the magnitude of tempe... more Using 30 years of climate records from 20 weather stations, we investigate the magnitude of temperature and precipitation change, and change in the length of the growing season between 1961 and 1990. Special attention is paid to the period between 1981 and 1990, because recent research suggests that, during this time span, forest productivity may have increased in the northern latitudes. In order to understand the importance of changes in climate on forest growth, we use the ecosystem model FOREST-BGC as a diagnostic tool to predict the annual net primary production (NPP). The results of our study indicate: no change in precipitation between 1961 and 1990; a signi®cant (0.05) increase in mean annual temperature of 0.728C, mean annual minimum temperature (0.808C), winter temperature (2.368C) as well as an increase in the length of the temperaturecontrolled growing season by 11 days, resulting in a signi®cant increase in diameter increment obtained from 1179 cores of Norway spruce across Austria. The trends in NPP are consistent with observed increment rates validating the use of biogeochemical modeling as a diagnostic tool to search for possible causes on changing environmental conditions.
Global Change Biology, 2017
Tree mortality is an important process in forest ecosystems, frequently hypothesized to be highly... more Tree mortality is an important process in forest ecosystems, frequently hypothesized to be highly climate sensitive. Yet, tree death remains one of the least understood processes of forest dynamics. Recently, changes in tree mortality have been observed in forests around the globe, which could profoundly affect ecosystem functioning and services provisioning to society. We describe continental-scale patterns of recent tree mortality from the only consistent pan-European forest monitoring network, identifying recent mortality hotspots in southern and northern Europe. Analyzing 925,462 annual observations of 235,895 trees between 2000 and 2012, we determine the influence of climate variability and tree age on interannual variation in tree mortality using Cox proportional hazard models. Warm summers as well as high seasonal variability in precipitation increased the likelihood of tree death. However, our data also suggest that reduced cold-induced mortality could compensate increased mortality related to peak temperatures in a warming climate. Besides climate variability, age was an important driver of tree mortality, with individual mortality probability decreasing with age over the first century of a trees life. A considerable portion of the observed variation in tree mortality could be explained by satellitederived net primary productivity, suggesting that widely available remote sensing products can be used as an early warning indicator of widespread tree mortality. Our findings advance the understanding of patterns of large-scale tree mortality by demonstrating the influence of seasonal and diurnal climate variation, and highlight the potential of state-of-the-art remote sensing to anticipate an increased likelihood of tree mortality in space and time.
Annals of Forest Science, 2016
Daily weather data are an important constraint for diverse applications in ecosystem research. In... more Daily weather data are an important constraint for diverse applications in ecosystem research. In particular, temperature and precipitation are the main drivers for forest ecosystem productivity. Mechanistic modeling theory heavily relies on daily values for minimum and maximum temperatures, precipitation, incident solar radiation and vapor pressure. These data are usually provided by interpolation techniques using measured values from surrounding stations
Ozone is one of the most important damaging air pollutants for forests in Austria. The mean atmos... more Ozone is one of the most important damaging air pollutants for forests in Austria. The mean atmospheric ozone concentration varies between 22.5 and 51.5 ppb (parts per billion) depending on altitude. Based on the emissions of the precursor substances (nitrous oxides and volatile hydrocarbons), the concentrations increase around 0.2 ppb per year and exceed the threshold for effects on plants.
GAIA - Ecological Perspectives for Science and Society, 2014
FarmClim aims at contributing to a more considerate use of nitrogen in Austrian agriculture. The ... more FarmClim aims at contributing to a more considerate use of nitrogen in Austrian agriculture. The transdisciplinary research project attempts to tackle the “science-policy gap” by using a participatory approach, that is, stakeholders influence the research process as much as the scientists strive for the implementation of their ideas. This paper describes the project design and communication processes. Full integration of practice partners adds to the complexity of the project's structure, but brings consider able benefits right from the outset. Taking advantage of the existing institutional setting of FarmClim partners, we expect to maintain expert consultancy beyond the lifetime of the project, helping agriculture to meet the challenges of environmental and economic performance of a producing agriculture.
Sustainable Forest Management
ABSTRACT The aim of this chapter is to review different approaches for simulating forest developm... more ABSTRACT The aim of this chapter is to review different approaches for simulating forest development in regeneration modeling. The features, shortcomings, further needs and trends of regeneration modeling are presented and discussed in the context of mechanistic, gap, statistical and nonparametric forest models. The data requirements are also described. Special emphasis is put on supplying information for modelers applying individual-tree models in uneven-aged stands.
Forest Ecology and Management, 2012
Large scale forest productivity estimates are of increasing interest as more demands are made on ... more Large scale forest productivity estimates are of increasing interest as more demands are made on forest resources. In principle three different methods are currently available: (i) forest growth data from forest research plots and/or forest inventory sampling points based on repeated tree observations, (ii) flux tower observations which record the gas exchange of the plant atmosphere interactions for a given vegetation type, and (iii) remotely sensed data for a continuous cover of net primary productivity estimates. In this paper we focus on the conceptual challenge in comparing ''space based'' moderate resolution imaging spectroradiometer (MODIS) satellite driven net primary production (NPP) vs. terrestrial ''ground based'' productivity estimates using forest increment data from 151 long term research plots with a well documented management history. The Austrian biomass functions are applied to derive ground based NPP estimates based on repeated tree observations from the plots. In addition we use BIOME-BGC as a diagnostic tool for exploring conceptual constraints among the two methods. The results of the study can be summarized as follows: (i) MODIS satellite driven annual NPP estimates provide a continuous productivity estimate across Austria and no significant differences between different daily climate input data sets were evident. (ii) MODIS NPP predictions provide forest productivity estimates of fully stocked forests with a complete crown cover. This is confirmed by the results of spin-up runs of the BIOME-BGC model. (iii) Terrestrial driven NPP predictions using the Austrian biomass functions compared well with MODIS driven estimates after addressing stand density effects of the forest plot data. The influence of stand density were known to be an integral component in reconciling ''space based'' satellite vs. ''ground based'' derived forest productivity estimates. After addressing stand density, computed forest productivity estimates compared well with MODIS-based estimates. This suggests that combining both methods will enhance our ability to generate forest productivity assessments across large forest areas.
Forest Ecology and Management, 2007
Large-scale ecosystem models are designed to reproduce and quantify ecosystem processes. Based on... more Large-scale ecosystem models are designed to reproduce and quantify ecosystem processes. Based on plant functions or species-specific parameter sets, the energy, carbon, nitrogen and water cycles of different ecosystems are assessed. These models have been proven to be important tools to investigate ecosystem fluxes as they are derived by plant, site and environmental factors. The general model approach assumes uniform and fully stocked forests but since most European forests are managed (e.g., thinned) it is essential to understand the limits and precision of such models when applied to managed forest ecosystems. The purpose of this study is to investigate and incorporate common forest management practices within the large-scale ecosystem model Biome-BGC. Using ''Monte-Carlo'' simulations we analyze the theoretical response to current model settings assuming steadily decreasing changes in stand density. Results of the MC simulations as well as the comparison with measured data suggest that the resulting predictions will be biased. Using long-term experimental plots of Norway spruce (Picea abies L. Karst.) and common beech (Fagus sylvatica L.) forests with a well-documented thinning history, we propose a thinning subroutine, which addresses the changes in allocation patterns after stand density changes. Validation tests of improved model structure across different long-term experimental sites in Central Europe revealed unbiased and consistent simulation results.
Remote Sensing, 2016
Net primary production (NPP) is an important ecological metric for studying forest ecosystems and... more Net primary production (NPP) is an important ecological metric for studying forest ecosystems and their carbon sequestration, for assessing the potential supply of food or timber and quantifying the impacts of climate change on ecosystems. The global MODIS NPP dataset using the MOD17 algorithm provides valuable information for monitoring NPP at 1-km resolution. Since coarse-resolution global climate data are used, the global dataset may contain uncertainties for Europe. We used a 1-km daily gridded European climate data set with the MOD17 algorithm to create the regional NPP dataset MODIS EURO. For evaluation of this new dataset, we compare MODIS EURO with terrestrial driven NPP from analyzing and harmonizing forest inventory data (NFI) from 196,434 plots in 12 European countries as well as the global MODIS NPP dataset for the years 2000 to 2012. Comparing these three NPP datasets, we found that the global MODIS NPP dataset differs from NFI NPP by 26%, while MODIS EURO only differs by 7%. MODIS EURO also agrees with NFI NPP across scales (from continental, regional to country) and gradients (elevation, location, tree age, dominant species, etc.). The agreement is particularly good for elevation, dominant
Forstwissenschaftliches Centralblatt, 2002
The present paper documents the practical applicability of growth simulators, gives an overview o... more The present paper documents the practical applicability of growth simulators, gives an overview of current model approaches, defines standards for the description and evaluation of growth models and growth simulators and indicates research needs. The recommendations aim to give users of growth simulators confidence in the transition to modern prediction systems and to increase the level of acceptance of new information technologies. The recommendations provide developers with guidelines for model description, model evaluation and software development and thus contribute towards efficient cooperation .
There is an increasing demand to include biodiversity assessments as an additional management inp... more There is an increasing demand to include biodiversity assessments as an additional management input within silvicultural decision making. A number of forest models are in use to support forest management planning. However, none of these models was explicitly designed to consider the biodiversity of forest ecosystems and how this may change under different silvicultural treatments. In this paper prominent attributes and measures of biodiversity and the data requirements for their calculation are identified based on a review of the literature. Existing forest models are classified with respect to the general modeling approach (i.e. empirical vs. process-based models), structural attributes and phenomena considered. After comparing the required data for biodiversity assessments and the available output of forest model types, we discuss to what extent existing models can satisfy the information needs for biodiversity assessments at the stand level. The main conclusion is that an extensi...
Forest Ecology and Management, 2005
The impacts that stand treatments have on carbon, nitrogen and water cycles is a key question rel... more The impacts that stand treatments have on carbon, nitrogen and water cycles is a key question relating the sustainability of forests to individual forest management decisions. While the response of the above ground carbon cycle may be relatively easy to measure and is well understood, e.g. volume growth response due to thinning, the impact of stand treatment and different harvesting scenarios on the water, and nutritional status of the remaining trees and site as well as on the below ground carbon and nitrogen cycle is much more difficult to assess due to the difficulty of obtaining reliable data. An alternative that eliminates the need for detailed site-specific data is to use existing models that were explicitly designed for studying biogeochemical processes. In this paper we test and evaluate the applicability of a species-specific mechanistic biogeochemical model to assess the impact of different harvesting scenarios after thinning. Data are available from 36 Norway spruce stands covering three regions each with three harvesting scenarios after thinning and four replications. The different harvesting scenarios applied are: (1) whole tree harvest, (2) whole tree harvest after one vegetation period, i.e. without needles, and (3) commercial stem wood harvest. The modeling results suggest that the variant 3 exhibited the highest growth efficiency, a measure of net carbon uptake or growth, versus all other harvesting methods. This is confirmed by the available field observations. Nitrogen, an indicator of nutrient supply, behaved similarly. The important exception was nitrogen plant uptake, which was lower immediately after thinning on the sites where the lowest amount of biomass was removed. Significant relationships exist between observed versus modeled stand volume and volume growth suggesting that mechanistic modeling is a suitable diagnostic tool for analyzing the impacts of different management practices and thus, such models can be efficiently used to enhance silvicultural decision-making.
Forest Ecology and Management, 1999
Using 30 years of climate records from 20 weather stations, we investigate the magnitude of tempe... more Using 30 years of climate records from 20 weather stations, we investigate the magnitude of temperature and precipitation change, and change in the length of the growing season between 1961 and 1990. Special attention is paid to the period between 1981 and 1990, because recent research suggests that, during this time span, forest productivity may have increased in the northern latitudes. In order to understand the importance of changes in climate on forest growth, we use the ecosystem model FOREST-BGC as a diagnostic tool to predict the annual net primary production (NPP). The results of our study indicate: no change in precipitation between 1961 and 1990; a signi®cant (0.05) increase in mean annual temperature of 0.728C, mean annual minimum temperature (0.808C), winter temperature (2.368C) as well as an increase in the length of the temperaturecontrolled growing season by 11 days, resulting in a signi®cant increase in diameter increment obtained from 1179 cores of Norway spruce across Austria. The trends in NPP are consistent with observed increment rates validating the use of biogeochemical modeling as a diagnostic tool to search for possible causes on changing environmental conditions.
Global Change Biology, 2017
Tree mortality is an important process in forest ecosystems, frequently hypothesized to be highly... more Tree mortality is an important process in forest ecosystems, frequently hypothesized to be highly climate sensitive. Yet, tree death remains one of the least understood processes of forest dynamics. Recently, changes in tree mortality have been observed in forests around the globe, which could profoundly affect ecosystem functioning and services provisioning to society. We describe continental-scale patterns of recent tree mortality from the only consistent pan-European forest monitoring network, identifying recent mortality hotspots in southern and northern Europe. Analyzing 925,462 annual observations of 235,895 trees between 2000 and 2012, we determine the influence of climate variability and tree age on interannual variation in tree mortality using Cox proportional hazard models. Warm summers as well as high seasonal variability in precipitation increased the likelihood of tree death. However, our data also suggest that reduced cold-induced mortality could compensate increased mortality related to peak temperatures in a warming climate. Besides climate variability, age was an important driver of tree mortality, with individual mortality probability decreasing with age over the first century of a trees life. A considerable portion of the observed variation in tree mortality could be explained by satellitederived net primary productivity, suggesting that widely available remote sensing products can be used as an early warning indicator of widespread tree mortality. Our findings advance the understanding of patterns of large-scale tree mortality by demonstrating the influence of seasonal and diurnal climate variation, and highlight the potential of state-of-the-art remote sensing to anticipate an increased likelihood of tree mortality in space and time.