Tropospheric ozone (O 3 ) is a phytotoxic air pollutant and the O 3 -induced visible foliar injur... more Tropospheric ozone (O 3 ) is a phytotoxic air pollutant and the O 3 -induced visible foliar injury (O 3 VFI) is a biomarker. A recently developed Free-air O 3 eXposure (FO 3 X) is a promising facility to verify field-observed “O 3 -like” VFIs and to establish a flux-based threshold for the O 3 VFI onset. The present study compared O 3 -like VFI registered in the southern European forest sites with actual O 3 VFI observed in a FO 3 X experiment. The O 3 -like VFIs were evaluated by eye in forests and thus it was subjective. According to the imaging analysis, we firstly demonstrated that major parts of the colors were similar in the field and the FO 3 X. The color pallets for O 3 VFI was species-specific and considered a advanced tool for the O 3 VFI diagnosis. In addition, we calculated a flux-based threshold for the O 3 VFI onset at the FO 3 X based on a Phytotoxic Ozone Dose (POD 1 ), which ranged from 4.9 to 18.1 mmol m −2 POD 1 . This FO 3 X-derived threshold partly explained but...
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium
The aim of this study was to evaluate the utility of Sentinel-1/2 time-series for monitoring sele... more The aim of this study was to evaluate the utility of Sentinel-1/2 time-series for monitoring selective logging in temperate forests. Ten stands were selectively logged with 5 to 28% of the existing growing stock volume being extracted. The analysis was focused on backscatter coefficient and surface reflectance changes for dates immediately prior and past the logging period. Monthly information on leaf area index (from terrestrial laser scanning) and vegetation water content (from destructive sampling) was used to support the analysis. The analysis suggested that monitoring selective logging using Sentinel-1/2 imagery is challenging in temperate montane forests due to a range of factors, including logging time and duration, saturation of C-band wavelength, and relatively small changes in canopy cover that cannot be reliably picked up by the optical sensor.
Atmospheric pollutants over the last century have led to increased negative impacts on the enviro... more Atmospheric pollutants over the last century have led to increased negative impacts on the environment, especially on forest ecosystems. In the Baia Mare region of Romania, the influence of pollution on the neighboring forests of the municipality has been reported since 1970, and its negative effects have been reported mainly in the form of reduced tree growth, which implies significant losses of wood biomass. The objective of this study is to analyze the temporal and spatial effect of industrial pollution on the auxological processes of beech trees in this region. Quantification of auxological changes was performed by analyzing the resilience, recovery and resistance indices. The most intense negative effect of local pollution with heavy metal dusts, sulfur and nitrogen oxides, and sulfuric acid vapors, on the auxological processes of beech trees was found in the period 1960–1990, with a maximum in the period 1970–1980, when the mining activity was at its highest intensity. Beech t...
At forest sites, phytotoxic tropospheric ozone (O3) can be monitored with continuously operating,... more At forest sites, phytotoxic tropospheric ozone (O3) can be monitored with continuously operating, active monitors (AM) or passive, cumulative samplers (PM). For the first time, we present evidence that the sustainability of active monitoring is better than that of passive sensors, as the environmental, economic, and social costs are usually lower in the former than in the latter. By using data collected in the field, environmental, social, and economic costs were analyzed. The study considered monitoring sites at three distances from a control station in Italy (30, 400, and 750 km), two forest types (deciduous and Mediterranean evergreen), and three time windows (5, 10, and 20 years of monitoring). AM resulted in more convenience than PM, even after 5 years, in terms of O3 depletion, global warming, and photochemical O3 creation potential, suggesting that passive monitoring of ozone is not environmentally sustainable, especially for long time periods. AM led to savings ranging from ...
Dead wood (DW) is an important component of sustainable forest management and climate change miti... more Dead wood (DW) is an important component of sustainable forest management and climate change mitigation. Three research plots (each with an area of 1 ha), located in virgin forests in the Southern Carpathians (Semenic P20, Retezat–Zănoaga, and Făgăraș–Șinca), were installed in order to study the synergies between DW and climate change mitigation effects. Data on the dendrometric characteristics of standing and lying DW, the species, and the degree of decay were recorded. The aboveground biomass (AGB) and carbon stock (CS) of the DW were also determined. The DW volume was between 48 m3·ha−1 and 148 m3·ha−1, with the total volume (dead and alive) ranging between 725 m3·ha−1 and 966 m3·ha−1. The DW volume distribution shows a decreasing trend, with the most suitable theoretical distributions for describing this being the lognormal, the 2P Weibull, and the 2P-Gamma. The AGB ranged between 17 t·ha−1 and 30 t·ha−1 and showed a decreasing trend according to altitude. The CS was between 8 t...
The current paper tested the hypothesis that TLS through its high accuracy, increased spatial res... more The current paper tested the hypothesis that TLS through its high accuracy, increased spatial resolution, portability, equivalenting în high temporal resolution, automated processing and unlimited revisiting capabilities of the scene once record ed, might represent the best available technology for phenological evaluation. Phenology observations represent one of the most accurate methods for evaluating the response of plant species to various climate conditions and climate changes. The main objective of this research was to identify the pattems pf early vegetation stages in the context of a reduced precipitation regime through terrestrial scanning technique. The research was carried out in a mixed forest stand ( Carpinus betulus, Acer campestre, Tilia cordata, Quercus robur) with the focus of more precisely identifying the pattem of early vegetation development. The phenological processes analysis was done at an increased spatial and temporal resolution, on specific horizontal layer...
Knowledge of intra-annual tree growth dynamics allow a better understanding of tree reaction to s... more Knowledge of intra-annual tree growth dynamics allow a better understanding of tree reaction to short term climate variation. The main objective of our study was modelling intra-annual dynamics of basal area increment (BAI) in four level II plots in Romania, composed of pedunculate oak (Quercus robur L.), sessile oak (Q. petraea (Matt.) Liebl.), Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.), which are placed in representative forest ecosystems, as well as in climatic and altitudinal conditions. Between 2010 and 2014, for a number of 60 trees (15 for each plot and species), the growth variations of the selected trees were recorded bimonthly using permanent girth bands. Seasonal dynamics of radial increment were modelled using Gompertz functions. Results confirm that each year the growing season period is different for each location. For pedunculate and sessile oak a common onset of the growth was observed during the whole period, except 2012. The sam...
With an overarching goal of addressing global and regional sustainability challenges, Long Term S... more With an overarching goal of addressing global and regional sustainability challenges, Long Term Socio-Ecological Research Platforms (LTSER) aim to conduct place-based research, to collect and synthesize both environmental and socio-economic data, and to involve a broader stakeholder pool to set the research agenda. To date there have been few studies examining 2 Corresponding author, jand@ceh.ac.uk 3 Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK 4 Faculty of Architecture and Town Planning, Technion Israel Institute of Technology, Haifa, 32000, Israel 5 Environment Agency Austria, Spittelauer Lände 5, 1090 Vienna, Austria 6 Irstea Ur Maly, 5 rue de la Doua, Villeurbanne, France 7 Dead Sea and Arava Science Center, Mitzpe Ramon, Israel 8 CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto. Campus Agrário de Vairão, Vairão, Portugal and CEABN/InBio, Centro de Ecologia Aplicada “Professor Baeta Neves”, Ins...
Research Highlights: Carpathian forests hold high ecological and economic value while generating ... more Research Highlights: Carpathian forests hold high ecological and economic value while generating conservation concerns, with some of these forests being among the few remaining temperate virgin forests in Europe. Carpathian forests partially lost their original integrity due to their management. Climate change has also gradually contributed to forest changes due to its modification of the environmental conditions. Background and Objectives: Understanding trees’ responses to past climates and forms of management is critical in foreseeing the responses of forests to future conditions. This study aims (1) to determine the sensitivity of Carpathian forests to past climates using dendrochronological records and (2) to describe the effects that climate change and management will have on the attributes of Carpathian forests, with a particular focus on the different response of pure and mixed forests. Materials and Methods: To this end, we first analysed the past climate-induced growth chan...
Forests play an important role in biodiversity conservation, being one of the main providers of e... more Forests play an important role in biodiversity conservation, being one of the main providers of ecosystem services, according to the Economics of Ecosystems and Biodiversity. The functions and ecosystem services provided by forests are various concerning the natural capital and the socio-economic systems. Past decades of remote-sensing advances make it possible to address a large set of variables, including both biophysical parameters and ecological indicators, that characterize forest ecosystems and their capacity to supply services. This research aims to identify and implement existing methods that can be used for evaluating ecosystem services by employing airborne and terrestrial stationary laser scanning on plots from the Southern Carpathian mountains. Moreover, this paper discusses the adaptation of field-based approaches for evaluating ecological indicators to automated processing techniques based on airborne and terrestrial stationary laser scanning (ALS and TLS). Forest ecos...
Background and Purpose: Romania’s forests are of globally significant value due to their natural ... more Background and Purpose: Romania’s forests are of globally significant value due to their natural characteristics, as similar forests in some other parts of the world have been lost forever. These types of forests, so-called "virgin" and "quasi-virgin (old growth)" forests, are also identified in the Buzau Mountains, which are part of the Eastern Carpathians in Romania (Curvature Region). Materials and Methods: To study and understand the structure and dynamics of primeval forest, four permanent one-hectare research plots were installed in the Penteleu Mountains, part of the Buzau Mountains. All trees with a diameter at breast height (DBH) greater than 80 mm were measured and their main dendrometric characteristics (DBH, height and social position) registered. The forest structure was analysed by fitting different theoretical distribution functions (beta, gamma, gamma 3P, gamma 3P mixt, loglogistic 3p, lognormal 3P and Weibull 3p). The structural homogeneity of th...
Oaks are among the most important broad-leaved species in Romanian forests from both an economic ... more Oaks are among the most important broad-leaved species in Romanian forests from both an economic and socio-ecological point of view. A significant decline of these species has been observed, which was first evident in various studies and investigations followed by the more results of interdisciplinary research performed in intensive monitoring plots (level II) showing that the decline is climate induced. Thus, it is important to understand the climate change conditions and factors that influence Quercus spp. Typical dendroclimatological investigations were conducted on an intensive forest monitoring network based on four oak species (Q. robur, Q. petraea, Q.cerris, and Q. frainetto) in 7 permanent plots placed in southern Romania. Three patterns of climate-growth relationships were identified and discerned in accordance with the Quercus species. All oak species were found to have a positive correlation with the level of precipitation. In addition, the intensity and level of signific...
Tropospheric ozone (O 3 ) is a phytotoxic air pollutant and the O 3 -induced visible foliar injur... more Tropospheric ozone (O 3 ) is a phytotoxic air pollutant and the O 3 -induced visible foliar injury (O 3 VFI) is a biomarker. A recently developed Free-air O 3 eXposure (FO 3 X) is a promising facility to verify field-observed “O 3 -like” VFIs and to establish a flux-based threshold for the O 3 VFI onset. The present study compared O 3 -like VFI registered in the southern European forest sites with actual O 3 VFI observed in a FO 3 X experiment. The O 3 -like VFIs were evaluated by eye in forests and thus it was subjective. According to the imaging analysis, we firstly demonstrated that major parts of the colors were similar in the field and the FO 3 X. The color pallets for O 3 VFI was species-specific and considered a advanced tool for the O 3 VFI diagnosis. In addition, we calculated a flux-based threshold for the O 3 VFI onset at the FO 3 X based on a Phytotoxic Ozone Dose (POD 1 ), which ranged from 4.9 to 18.1 mmol m −2 POD 1 . This FO 3 X-derived threshold partly explained but...
IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium
The aim of this study was to evaluate the utility of Sentinel-1/2 time-series for monitoring sele... more The aim of this study was to evaluate the utility of Sentinel-1/2 time-series for monitoring selective logging in temperate forests. Ten stands were selectively logged with 5 to 28% of the existing growing stock volume being extracted. The analysis was focused on backscatter coefficient and surface reflectance changes for dates immediately prior and past the logging period. Monthly information on leaf area index (from terrestrial laser scanning) and vegetation water content (from destructive sampling) was used to support the analysis. The analysis suggested that monitoring selective logging using Sentinel-1/2 imagery is challenging in temperate montane forests due to a range of factors, including logging time and duration, saturation of C-band wavelength, and relatively small changes in canopy cover that cannot be reliably picked up by the optical sensor.
Atmospheric pollutants over the last century have led to increased negative impacts on the enviro... more Atmospheric pollutants over the last century have led to increased negative impacts on the environment, especially on forest ecosystems. In the Baia Mare region of Romania, the influence of pollution on the neighboring forests of the municipality has been reported since 1970, and its negative effects have been reported mainly in the form of reduced tree growth, which implies significant losses of wood biomass. The objective of this study is to analyze the temporal and spatial effect of industrial pollution on the auxological processes of beech trees in this region. Quantification of auxological changes was performed by analyzing the resilience, recovery and resistance indices. The most intense negative effect of local pollution with heavy metal dusts, sulfur and nitrogen oxides, and sulfuric acid vapors, on the auxological processes of beech trees was found in the period 1960–1990, with a maximum in the period 1970–1980, when the mining activity was at its highest intensity. Beech t...
At forest sites, phytotoxic tropospheric ozone (O3) can be monitored with continuously operating,... more At forest sites, phytotoxic tropospheric ozone (O3) can be monitored with continuously operating, active monitors (AM) or passive, cumulative samplers (PM). For the first time, we present evidence that the sustainability of active monitoring is better than that of passive sensors, as the environmental, economic, and social costs are usually lower in the former than in the latter. By using data collected in the field, environmental, social, and economic costs were analyzed. The study considered monitoring sites at three distances from a control station in Italy (30, 400, and 750 km), two forest types (deciduous and Mediterranean evergreen), and three time windows (5, 10, and 20 years of monitoring). AM resulted in more convenience than PM, even after 5 years, in terms of O3 depletion, global warming, and photochemical O3 creation potential, suggesting that passive monitoring of ozone is not environmentally sustainable, especially for long time periods. AM led to savings ranging from ...
Dead wood (DW) is an important component of sustainable forest management and climate change miti... more Dead wood (DW) is an important component of sustainable forest management and climate change mitigation. Three research plots (each with an area of 1 ha), located in virgin forests in the Southern Carpathians (Semenic P20, Retezat–Zănoaga, and Făgăraș–Șinca), were installed in order to study the synergies between DW and climate change mitigation effects. Data on the dendrometric characteristics of standing and lying DW, the species, and the degree of decay were recorded. The aboveground biomass (AGB) and carbon stock (CS) of the DW were also determined. The DW volume was between 48 m3·ha−1 and 148 m3·ha−1, with the total volume (dead and alive) ranging between 725 m3·ha−1 and 966 m3·ha−1. The DW volume distribution shows a decreasing trend, with the most suitable theoretical distributions for describing this being the lognormal, the 2P Weibull, and the 2P-Gamma. The AGB ranged between 17 t·ha−1 and 30 t·ha−1 and showed a decreasing trend according to altitude. The CS was between 8 t...
The current paper tested the hypothesis that TLS through its high accuracy, increased spatial res... more The current paper tested the hypothesis that TLS through its high accuracy, increased spatial resolution, portability, equivalenting în high temporal resolution, automated processing and unlimited revisiting capabilities of the scene once record ed, might represent the best available technology for phenological evaluation. Phenology observations represent one of the most accurate methods for evaluating the response of plant species to various climate conditions and climate changes. The main objective of this research was to identify the pattems pf early vegetation stages in the context of a reduced precipitation regime through terrestrial scanning technique. The research was carried out in a mixed forest stand ( Carpinus betulus, Acer campestre, Tilia cordata, Quercus robur) with the focus of more precisely identifying the pattem of early vegetation development. The phenological processes analysis was done at an increased spatial and temporal resolution, on specific horizontal layer...
Knowledge of intra-annual tree growth dynamics allow a better understanding of tree reaction to s... more Knowledge of intra-annual tree growth dynamics allow a better understanding of tree reaction to short term climate variation. The main objective of our study was modelling intra-annual dynamics of basal area increment (BAI) in four level II plots in Romania, composed of pedunculate oak (Quercus robur L.), sessile oak (Q. petraea (Matt.) Liebl.), Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.), which are placed in representative forest ecosystems, as well as in climatic and altitudinal conditions. Between 2010 and 2014, for a number of 60 trees (15 for each plot and species), the growth variations of the selected trees were recorded bimonthly using permanent girth bands. Seasonal dynamics of radial increment were modelled using Gompertz functions. Results confirm that each year the growing season period is different for each location. For pedunculate and sessile oak a common onset of the growth was observed during the whole period, except 2012. The sam...
With an overarching goal of addressing global and regional sustainability challenges, Long Term S... more With an overarching goal of addressing global and regional sustainability challenges, Long Term Socio-Ecological Research Platforms (LTSER) aim to conduct place-based research, to collect and synthesize both environmental and socio-economic data, and to involve a broader stakeholder pool to set the research agenda. To date there have been few studies examining 2 Corresponding author, jand@ceh.ac.uk 3 Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian, EH26 0QB, UK 4 Faculty of Architecture and Town Planning, Technion Israel Institute of Technology, Haifa, 32000, Israel 5 Environment Agency Austria, Spittelauer Lände 5, 1090 Vienna, Austria 6 Irstea Ur Maly, 5 rue de la Doua, Villeurbanne, France 7 Dead Sea and Arava Science Center, Mitzpe Ramon, Israel 8 CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto. Campus Agrário de Vairão, Vairão, Portugal and CEABN/InBio, Centro de Ecologia Aplicada “Professor Baeta Neves”, Ins...
Research Highlights: Carpathian forests hold high ecological and economic value while generating ... more Research Highlights: Carpathian forests hold high ecological and economic value while generating conservation concerns, with some of these forests being among the few remaining temperate virgin forests in Europe. Carpathian forests partially lost their original integrity due to their management. Climate change has also gradually contributed to forest changes due to its modification of the environmental conditions. Background and Objectives: Understanding trees’ responses to past climates and forms of management is critical in foreseeing the responses of forests to future conditions. This study aims (1) to determine the sensitivity of Carpathian forests to past climates using dendrochronological records and (2) to describe the effects that climate change and management will have on the attributes of Carpathian forests, with a particular focus on the different response of pure and mixed forests. Materials and Methods: To this end, we first analysed the past climate-induced growth chan...
Forests play an important role in biodiversity conservation, being one of the main providers of e... more Forests play an important role in biodiversity conservation, being one of the main providers of ecosystem services, according to the Economics of Ecosystems and Biodiversity. The functions and ecosystem services provided by forests are various concerning the natural capital and the socio-economic systems. Past decades of remote-sensing advances make it possible to address a large set of variables, including both biophysical parameters and ecological indicators, that characterize forest ecosystems and their capacity to supply services. This research aims to identify and implement existing methods that can be used for evaluating ecosystem services by employing airborne and terrestrial stationary laser scanning on plots from the Southern Carpathian mountains. Moreover, this paper discusses the adaptation of field-based approaches for evaluating ecological indicators to automated processing techniques based on airborne and terrestrial stationary laser scanning (ALS and TLS). Forest ecos...
Background and Purpose: Romania’s forests are of globally significant value due to their natural ... more Background and Purpose: Romania’s forests are of globally significant value due to their natural characteristics, as similar forests in some other parts of the world have been lost forever. These types of forests, so-called "virgin" and "quasi-virgin (old growth)" forests, are also identified in the Buzau Mountains, which are part of the Eastern Carpathians in Romania (Curvature Region). Materials and Methods: To study and understand the structure and dynamics of primeval forest, four permanent one-hectare research plots were installed in the Penteleu Mountains, part of the Buzau Mountains. All trees with a diameter at breast height (DBH) greater than 80 mm were measured and their main dendrometric characteristics (DBH, height and social position) registered. The forest structure was analysed by fitting different theoretical distribution functions (beta, gamma, gamma 3P, gamma 3P mixt, loglogistic 3p, lognormal 3P and Weibull 3p). The structural homogeneity of th...
Oaks are among the most important broad-leaved species in Romanian forests from both an economic ... more Oaks are among the most important broad-leaved species in Romanian forests from both an economic and socio-ecological point of view. A significant decline of these species has been observed, which was first evident in various studies and investigations followed by the more results of interdisciplinary research performed in intensive monitoring plots (level II) showing that the decline is climate induced. Thus, it is important to understand the climate change conditions and factors that influence Quercus spp. Typical dendroclimatological investigations were conducted on an intensive forest monitoring network based on four oak species (Q. robur, Q. petraea, Q.cerris, and Q. frainetto) in 7 permanent plots placed in southern Romania. Three patterns of climate-growth relationships were identified and discerned in accordance with the Quercus species. All oak species were found to have a positive correlation with the level of precipitation. In addition, the intensity and level of signific...
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