The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform
Giuseppe Zerbi - One of the best experts on this subject based on the ideXlab platform.
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Forest ecosystem carbon accumulation during a secondary succession in the Eastern Prealps of Italy
Forestry, 2008Co-Authors: Giorgio Alberti, Alessandro Peressotti, Pietro Piussi, Giuseppe ZerbiAbstract:Summary Land use changes represent one of the most important components of global environmental change. In most European countries, the transformed economies and social conditions of previous decades have had consequences in terms of agriculture intensifi cation, industrialization and migration of people from the rural areas. As a consequence, areas of marginal agriculture were abandoned leading to secondary successions. This research studied the effects of the natural recovery of abandoned lands on carbon pools using a chronosequence approach of Mixed Ash ( Fraxinus excelsior L.) and sycamore ( Acer pseudoplatanus L.) stands in the Eastern Italian Prealps. A series of fi ve formerly cultivated sites spanning a range of 40 – 75 years since agricultural abandonment and a meadow were selected. The dominant sink for the atmospheric CO 2 within these secondary forests seems to be live wood while the soil played a much smaller role. The ecosystem carbon stock increased at a mean rate of 1.18 Mg C ha − 1 y − 1 during the chronosequence. However, a difference in the carbon accumulation in the different pools was detected.
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Aboveground biomass relationships for Mixed Ash (Fraxinus excelsior L. and Ulmus glabra Hudson) stands in Eastern Prealps of Friuli Venezia Giulia (Italy)
Annals of Forest Science, 2005Co-Authors: Giorgio Alberti, Patrick Candido, Alessandro Peressotti, Sheera Turco, Pietro Piussi, Giuseppe ZerbiAbstract:About 5% of forest area of Friuli Venezia Giulia (Italy) is covered by Mixed Ash stands. In most cases, these are secondary forest established on former pastures and grasslands in the last fifty years and they constitute an important resource from an economic point of view. This paper presents allometric equations describing tree size-shape relationships for Ash (Fraxinus excelsior L.) and wych elm (Ulmus glabra Hudson). Diameter at breast height explained most of the variability of the dependent variables (total stem volume, total aboveground, stem, branches and leaves biomass). Wood density variations with stem height and leaf area index (LAI) were also investigated.
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Aboveground biomass relationships for Mixed Ash (Fraxinus excelsior L. and Ulmus glabra Hudson) stands in Eastern Prealps of Friuli Venezia Giulia (Italy)
Annals of Forest Science, 2005Co-Authors: Giorgio Alberti, Patrick Candido, Alessandro Peressotti, Sheera Turco, Pietro Piussi, Giuseppe ZerbiAbstract:Environ 5 % de la surface forestiere de Friuli Venezia Giulia (Italie) est constituee de peuplements de frene en melange avec d'autres essences. Dans la plupart des cas, ce sont des forets secondaires installees sur des pâturages et des prairies au cours des cinquante dernieres annees. Elles constituent une importante ressource economique. Cet article presente les equations allometriques pour l'estimation de la biomasse aerienne pour le frene (Fraxinus excelsior L.) et pour l'orme de montagne (Ulmus glabra Hudson). Le diametre a hauteur de poitrine explique la majeure partie de la variabilite des variables suivantes: volume total de la tige, biomasse aerienne totale, biomasse de la tige, biomasse des branches et des feuilles. La variation de la densite de la tige avec la hauteur et l'indice foliaire (LAI) ont aussi ete consideres.
B. J. Williamson - One of the best experts on this subject based on the ideXlab platform.
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Characterization of respirable volcanic Ash from the Soufrière Hills volcano, Montserrat, with implications for human health hazards
Bulletin of Volcanology, 2003Co-Authors: C. J. Horwell, R. S. J. Sparks, T. S. Brewer, E. W. Llewellin, B. J. WilliamsonAbstract:Volcanic Ash, generated in the long-lived eruption of the Soufrière Hills volcano, Montserrat, is shown to contain respirable (sub-4 μ m) particles and cristobalite, a crystalline silica polymorph. Respirable particles of cristobalite can cause silicosis, raising the possibility that volcanic Ash is a respiratory health hazard. This study considers some of the main factors which affect human exposure to respirable volcanic Ash, namely, the composition and proportions of respirable Ash, and the composition and concentrations of airborne suspended particulates. The composition, size distribution and proportion (by weight) of respirable particles in representative samples of the Soufrière Hills tephra (dome-collapse Ash-fall deposits, dome-collapse pyroclastic-flow matrix, Vulcanian explosion Ash and Mixed Ash) have been characterized. Dome-collapse Ash-fall deposits are significantly richer in respirable particles (12 wt%) than the other tephra samples, in particular the matrices of dome-collapse pyroclastic-flow deposits (3 wt%). Within the respirable fraction, dome-collapse Ash contains the highest proportion of crystalline silica particles (20–27 number%, of which 97 wt% is cristobalite), compared with other primary tephra types (0.4–5.6 number%). This enrichment of crystalline silica in the dome-collapse Ash is most pronounced in the very fine particle fraction (sub-2 μ m). The results are explained as being due to significant size fractionation during fragmentation of pyroclastic flows, resulting in a fines-depleted dome-collapse matrix and a fines-rich dome-collapse Ash deposit. For all sample types, the sub-4 μ m fraction comprises 45–55 wt% of the sub-10 μ m fraction. Aeolian deposit, lahar deposit and airborne samples of suspended Ash, collected on filters, were characterized. These samples show enrichment of crystalline silica in the respirable fraction (10–18 number%). The results are consistent with Ash in the environment having a Mixed origin but originating predominantly from dome-collapse eruptions. The reworked Ash, however, contains low proportions of respirable Ash (∼3 wt%) compared to primary Ash samples. The concentration of Ash particles re-suspended by road vehicles on Montserrat is found to decrease exponentially with height above the ground, indicating higher exposure for children compared with adults: PM_4 concentration at 0.9 m (height of two-year-old child) is 3 times that at 1.8 m (adult height). The composition of the re-suspended road particles is similar to that re-suspended by the wind.
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Characterization of respirable volcanic Ash from the Soufrière Hills volcano, Montserrat, with implications for human health hazards
Bulletin of Volcanology, 2003Co-Authors: C. J. Horwell, R. S. J. Sparks, T. S. Brewer, E. W. Llewellin, B. J. WilliamsonAbstract:Volcanic Ash, generated in the long-lived eruption of the Soufriere Hills volcano, Montserrat, is shown to contain respirable (sub-4 μm) particles and cristobalite, a crystalline silica polymorph. Respirable particles of cristobalite can cause silicosis, raising the possibility that volcanic Ash is a respiratory health hazard. This study considers some of the main factors which affect human exposure to respirable volcanic Ash, namely, the composition and proportions of respirable Ash, and the composition and concentrations of airborne suspended particulates. The composition, size distribution and proportion (by weight) of respirable particles in representative samples of the Soufriere Hills tephra (dome-collapse Ash-fall deposits, dome-collapse pyroclastic-flow matrix, Vulcanian explosion Ash and Mixed Ash) have been characterized. Dome-collapse Ash-fall deposits are significantly richer in respirable particles (12 wt%) than the other tephra samples, in particular the matrices of dome-collapse pyroclastic-flow deposits (3 wt%). Within the respirable fraction, dome-collapse Ash contains the highest proportion of crystalline silica particles (20–27 number%, of which 97 wt% is cristobalite), compared with other primary tephra types (0.4–5.6 number%). This enrichment of crystalline silica in the dome-collapse Ash is most pronounced in the very fine particle fraction (sub-2 μm). The results are explained as being due to significant size fractionation during fragmentation of pyroclastic flows, resulting in a fines-depleted dome-collapse matrix and a fines-rich dome-collapse Ash deposit. For all sample types, the sub-4 μm fraction comprises 45–55 wt% of the sub-10 μm fraction. Aeolian deposit, lahar deposit and airborne samples of suspended Ash, collected on filters, were characterized. These samples show enrichment of crystalline silica in the respirable fraction (10–18 number%). The results are consistent with Ash in the environment having a Mixed origin but originating predominantly from dome-collapse eruptions. The reworked Ash, however, contains low proportions of respirable Ash (∼3 wt%) compared to primary Ash samples. The concentration of Ash particles re-suspended by road vehicles on Montserrat is found to decrease exponentially with height above the ground, indicating higher exposure for children compared with adults: PM4 concentration at 0.9 m (height of two-year-old child) is 3 times that at 1.8 m (adult height). The composition of the re-suspended road particles is similar to that re-suspended by the wind.
Giorgio Alberti - One of the best experts on this subject based on the ideXlab platform.
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Forest ecosystem carbon accumulation during a secondary succession in the Eastern Prealps of Italy
Forestry, 2008Co-Authors: Giorgio Alberti, Alessandro Peressotti, Pietro Piussi, Giuseppe ZerbiAbstract:Summary Land use changes represent one of the most important components of global environmental change. In most European countries, the transformed economies and social conditions of previous decades have had consequences in terms of agriculture intensifi cation, industrialization and migration of people from the rural areas. As a consequence, areas of marginal agriculture were abandoned leading to secondary successions. This research studied the effects of the natural recovery of abandoned lands on carbon pools using a chronosequence approach of Mixed Ash ( Fraxinus excelsior L.) and sycamore ( Acer pseudoplatanus L.) stands in the Eastern Italian Prealps. A series of fi ve formerly cultivated sites spanning a range of 40 – 75 years since agricultural abandonment and a meadow were selected. The dominant sink for the atmospheric CO 2 within these secondary forests seems to be live wood while the soil played a much smaller role. The ecosystem carbon stock increased at a mean rate of 1.18 Mg C ha − 1 y − 1 during the chronosequence. However, a difference in the carbon accumulation in the different pools was detected.
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Aboveground biomass relationships for Mixed Ash (Fraxinus excelsior L. and Ulmus glabra Hudson) stands in Eastern Prealps of Friuli Venezia Giulia (Italy)
Annals of Forest Science, 2005Co-Authors: Giorgio Alberti, Patrick Candido, Alessandro Peressotti, Sheera Turco, Pietro Piussi, Giuseppe ZerbiAbstract:About 5% of forest area of Friuli Venezia Giulia (Italy) is covered by Mixed Ash stands. In most cases, these are secondary forest established on former pastures and grasslands in the last fifty years and they constitute an important resource from an economic point of view. This paper presents allometric equations describing tree size-shape relationships for Ash (Fraxinus excelsior L.) and wych elm (Ulmus glabra Hudson). Diameter at breast height explained most of the variability of the dependent variables (total stem volume, total aboveground, stem, branches and leaves biomass). Wood density variations with stem height and leaf area index (LAI) were also investigated.
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Aboveground biomass relationships for Mixed Ash (Fraxinus excelsior L. and Ulmus glabra Hudson) stands in Eastern Prealps of Friuli Venezia Giulia (Italy)
Annals of Forest Science, 2005Co-Authors: Giorgio Alberti, Patrick Candido, Alessandro Peressotti, Sheera Turco, Pietro Piussi, Giuseppe ZerbiAbstract:Environ 5 % de la surface forestiere de Friuli Venezia Giulia (Italie) est constituee de peuplements de frene en melange avec d'autres essences. Dans la plupart des cas, ce sont des forets secondaires installees sur des pâturages et des prairies au cours des cinquante dernieres annees. Elles constituent une importante ressource economique. Cet article presente les equations allometriques pour l'estimation de la biomasse aerienne pour le frene (Fraxinus excelsior L.) et pour l'orme de montagne (Ulmus glabra Hudson). Le diametre a hauteur de poitrine explique la majeure partie de la variabilite des variables suivantes: volume total de la tige, biomasse aerienne totale, biomasse de la tige, biomasse des branches et des feuilles. La variation de la densite de la tige avec la hauteur et l'indice foliaire (LAI) ont aussi ete consideres.
C. J. Horwell - One of the best experts on this subject based on the ideXlab platform.
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Characterization of respirable volcanic Ash from the Soufrière Hills volcano, Montserrat, with implications for human health hazards
Bulletin of Volcanology, 2003Co-Authors: C. J. Horwell, R. S. J. Sparks, T. S. Brewer, E. W. Llewellin, B. J. WilliamsonAbstract:Volcanic Ash, generated in the long-lived eruption of the Soufrière Hills volcano, Montserrat, is shown to contain respirable (sub-4 μ m) particles and cristobalite, a crystalline silica polymorph. Respirable particles of cristobalite can cause silicosis, raising the possibility that volcanic Ash is a respiratory health hazard. This study considers some of the main factors which affect human exposure to respirable volcanic Ash, namely, the composition and proportions of respirable Ash, and the composition and concentrations of airborne suspended particulates. The composition, size distribution and proportion (by weight) of respirable particles in representative samples of the Soufrière Hills tephra (dome-collapse Ash-fall deposits, dome-collapse pyroclastic-flow matrix, Vulcanian explosion Ash and Mixed Ash) have been characterized. Dome-collapse Ash-fall deposits are significantly richer in respirable particles (12 wt%) than the other tephra samples, in particular the matrices of dome-collapse pyroclastic-flow deposits (3 wt%). Within the respirable fraction, dome-collapse Ash contains the highest proportion of crystalline silica particles (20–27 number%, of which 97 wt% is cristobalite), compared with other primary tephra types (0.4–5.6 number%). This enrichment of crystalline silica in the dome-collapse Ash is most pronounced in the very fine particle fraction (sub-2 μ m). The results are explained as being due to significant size fractionation during fragmentation of pyroclastic flows, resulting in a fines-depleted dome-collapse matrix and a fines-rich dome-collapse Ash deposit. For all sample types, the sub-4 μ m fraction comprises 45–55 wt% of the sub-10 μ m fraction. Aeolian deposit, lahar deposit and airborne samples of suspended Ash, collected on filters, were characterized. These samples show enrichment of crystalline silica in the respirable fraction (10–18 number%). The results are consistent with Ash in the environment having a Mixed origin but originating predominantly from dome-collapse eruptions. The reworked Ash, however, contains low proportions of respirable Ash (∼3 wt%) compared to primary Ash samples. The concentration of Ash particles re-suspended by road vehicles on Montserrat is found to decrease exponentially with height above the ground, indicating higher exposure for children compared with adults: PM_4 concentration at 0.9 m (height of two-year-old child) is 3 times that at 1.8 m (adult height). The composition of the re-suspended road particles is similar to that re-suspended by the wind.
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Characterization of respirable volcanic Ash from the Soufrière Hills volcano, Montserrat, with implications for human health hazards
Bulletin of Volcanology, 2003Co-Authors: C. J. Horwell, R. S. J. Sparks, T. S. Brewer, E. W. Llewellin, B. J. WilliamsonAbstract:Volcanic Ash, generated in the long-lived eruption of the Soufriere Hills volcano, Montserrat, is shown to contain respirable (sub-4 μm) particles and cristobalite, a crystalline silica polymorph. Respirable particles of cristobalite can cause silicosis, raising the possibility that volcanic Ash is a respiratory health hazard. This study considers some of the main factors which affect human exposure to respirable volcanic Ash, namely, the composition and proportions of respirable Ash, and the composition and concentrations of airborne suspended particulates. The composition, size distribution and proportion (by weight) of respirable particles in representative samples of the Soufriere Hills tephra (dome-collapse Ash-fall deposits, dome-collapse pyroclastic-flow matrix, Vulcanian explosion Ash and Mixed Ash) have been characterized. Dome-collapse Ash-fall deposits are significantly richer in respirable particles (12 wt%) than the other tephra samples, in particular the matrices of dome-collapse pyroclastic-flow deposits (3 wt%). Within the respirable fraction, dome-collapse Ash contains the highest proportion of crystalline silica particles (20–27 number%, of which 97 wt% is cristobalite), compared with other primary tephra types (0.4–5.6 number%). This enrichment of crystalline silica in the dome-collapse Ash is most pronounced in the very fine particle fraction (sub-2 μm). The results are explained as being due to significant size fractionation during fragmentation of pyroclastic flows, resulting in a fines-depleted dome-collapse matrix and a fines-rich dome-collapse Ash deposit. For all sample types, the sub-4 μm fraction comprises 45–55 wt% of the sub-10 μm fraction. Aeolian deposit, lahar deposit and airborne samples of suspended Ash, collected on filters, were characterized. These samples show enrichment of crystalline silica in the respirable fraction (10–18 number%). The results are consistent with Ash in the environment having a Mixed origin but originating predominantly from dome-collapse eruptions. The reworked Ash, however, contains low proportions of respirable Ash (∼3 wt%) compared to primary Ash samples. The concentration of Ash particles re-suspended by road vehicles on Montserrat is found to decrease exponentially with height above the ground, indicating higher exposure for children compared with adults: PM4 concentration at 0.9 m (height of two-year-old child) is 3 times that at 1.8 m (adult height). The composition of the re-suspended road particles is similar to that re-suspended by the wind.
Pietro Piussi - One of the best experts on this subject based on the ideXlab platform.
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Forest ecosystem carbon accumulation during a secondary succession in the Eastern Prealps of Italy
Forestry, 2008Co-Authors: Giorgio Alberti, Alessandro Peressotti, Pietro Piussi, Giuseppe ZerbiAbstract:Summary Land use changes represent one of the most important components of global environmental change. In most European countries, the transformed economies and social conditions of previous decades have had consequences in terms of agriculture intensifi cation, industrialization and migration of people from the rural areas. As a consequence, areas of marginal agriculture were abandoned leading to secondary successions. This research studied the effects of the natural recovery of abandoned lands on carbon pools using a chronosequence approach of Mixed Ash ( Fraxinus excelsior L.) and sycamore ( Acer pseudoplatanus L.) stands in the Eastern Italian Prealps. A series of fi ve formerly cultivated sites spanning a range of 40 – 75 years since agricultural abandonment and a meadow were selected. The dominant sink for the atmospheric CO 2 within these secondary forests seems to be live wood while the soil played a much smaller role. The ecosystem carbon stock increased at a mean rate of 1.18 Mg C ha − 1 y − 1 during the chronosequence. However, a difference in the carbon accumulation in the different pools was detected.
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Aboveground biomass relationships for Mixed Ash (Fraxinus excelsior L. and Ulmus glabra Hudson) stands in Eastern Prealps of Friuli Venezia Giulia (Italy)
Annals of Forest Science, 2005Co-Authors: Giorgio Alberti, Patrick Candido, Alessandro Peressotti, Sheera Turco, Pietro Piussi, Giuseppe ZerbiAbstract:About 5% of forest area of Friuli Venezia Giulia (Italy) is covered by Mixed Ash stands. In most cases, these are secondary forest established on former pastures and grasslands in the last fifty years and they constitute an important resource from an economic point of view. This paper presents allometric equations describing tree size-shape relationships for Ash (Fraxinus excelsior L.) and wych elm (Ulmus glabra Hudson). Diameter at breast height explained most of the variability of the dependent variables (total stem volume, total aboveground, stem, branches and leaves biomass). Wood density variations with stem height and leaf area index (LAI) were also investigated.
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Aboveground biomass relationships for Mixed Ash (Fraxinus excelsior L. and Ulmus glabra Hudson) stands in Eastern Prealps of Friuli Venezia Giulia (Italy)
Annals of Forest Science, 2005Co-Authors: Giorgio Alberti, Patrick Candido, Alessandro Peressotti, Sheera Turco, Pietro Piussi, Giuseppe ZerbiAbstract:Environ 5 % de la surface forestiere de Friuli Venezia Giulia (Italie) est constituee de peuplements de frene en melange avec d'autres essences. Dans la plupart des cas, ce sont des forets secondaires installees sur des pâturages et des prairies au cours des cinquante dernieres annees. Elles constituent une importante ressource economique. Cet article presente les equations allometriques pour l'estimation de la biomasse aerienne pour le frene (Fraxinus excelsior L.) et pour l'orme de montagne (Ulmus glabra Hudson). Le diametre a hauteur de poitrine explique la majeure partie de la variabilite des variables suivantes: volume total de la tige, biomasse aerienne totale, biomasse de la tige, biomasse des branches et des feuilles. La variation de la densite de la tige avec la hauteur et l'indice foliaire (LAI) ont aussi ete consideres.