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Christoph Leuschner - One of the best experts on this subject based on the ideXlab platform.
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Climate Warming-Related Growth Decline Affects Fagus sylvatica, But Not Other Broad-Leaved Tree Species in Central European Mixed Forests
Ecosystems, 2015Co-Authors: Jorma Zimmermann, Markus Hauck, Choimaa Dulamsuren, Christoph LeuschnerAbstract:Climate warming is predicted to extend the duration and enhance the severity of summer droughts in Central Europe, which may pose a serious risk to forest productivity and forest health. Fagus sylvatica (European beech), the most abundant Tree species of Central Europe’s natural forest vegetation and one of the key species in forestry, is thought to be particularly vulnerable to drought. Here, we present a dendrochronological analysis in three mixed temperate Broad-Leaved forests along a precipitation gradient with the aim of comparing the climatic response of radial growth of F. sylvatica with the performance of four co-existing species ( Acer pseudoplatanus , A. platanoides , Quercus petraea , Fraxinus excelsior ). We hypothesized that Fagus is the most drought sensitive of the five species, which implies that it could lose its competitive advantage at drier sites in the course of climate warming. In support of this hypothesis, we found that F. sylvatica in all stands exhibited an increase in the number of negative pointer years and a decrease in radial increment in the driest stand since about 1980, in parallel to increasing summer temperatures and drought intensity. Such a response was missing in the other four species and may point to shifts in the competitive hierarchy in these mixed forests under a future warmer climate. We conclude that Central Europe’s forestry sector should consider carefully the risk of failure of beech in regions with relatively low and decreasing summer precipitation.
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Low light acclimation in five temperate Broad-Leaved Tree species of different successional status: the significance of a shade canopy
Annals of Forest Science, 2013Co-Authors: Nicole Legner, Stefan Fleck, Christoph LeuschnerAbstract:• Context Tree species differ largely in their capability to produce characteristic shade leaves with effective morphological and physiological acclimation to low light. • Aims By examining the sun/shade leaf differentiation in leaf morphology, foliar nitrogen and photosynthetic capacity in five temperate Tree species of different successional status, we aimed at identifying those leaf traits that determine the development of a typical shade crown with low light-acclimated leaves. • Methods Leaf morphology, foliar N content, photosynthetic capacity ( V _cmax, J _max and A _max) and leaf dark respiration ( R _d) were measured in the canopies of 26 adult Trees of Fraxinus , Acer , Carpinus , Tilia and Fagus species. • Results Six traits (the sun/shade leaf differentiation in specific leaf area, leaf size, A _max per leaf area or per mass, photosynthetic N use efficiency and R _d) were found to characterise best the degree of low light acclimation in shade leaves. All five species exhibited certain modifications in leaf morphology and/or physiology in response to low light; Fagus sylvatica showed the highest and Fraxinus excelsior the lowest shade leaf acclimation. • Conclusions Our results indicate that the five early/mid- to late-successional species have developed species-specific low light acclimation strategies in their shade crowns which differ in terms of the relative importance of leaf morphological and physiological acclimation.
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stem water storage in five coexisting temperate broad leaved Tree species significance temporal dynamics and dependence on Tree functional traits
Tree Physiology, 2013Co-Authors: Paul Kocher, Viviana Horna, Christoph LeuschnerAbstract:The functional role of internal water storage is increasingly well understood in tropical Trees and conifers, while temperate Broad-Leaved Trees have only rarely been studied. We examined the magnitude and dynamics of the use of stem water reserves for transpiration in five coexisting temperate Broad-Leaved Trees with largely different morphology and physiology (genera Fagus, Fraxinus, Tilia, Carpinus and Acer). We expected that differences in water storage patterns would mostly reflect species differences in wood anatomy (ring vs. diffuse-porous) and wood density. Sap flux density was recorded synchronously at five positions along the root-to-branch flow path of mature Trees (roots, three stem positions and branches) with high temporal resolution (2 min) and related to stem radius changes recorded with electronic point dendrometers. The daily amount of stored stem water withdrawn for transpiration was estimated by comparing the integrated flow at stem base and stem top. The tem poral coincidence of flows at different positions and apparent time lags were examined by cross- correlation analysis. Our results confirm that internal water stores play an important role in the four diffuse-porous species with estimated 5–12 kg day −1 being withdrawn on average in 25–28 m tall Trees representing 10–22% of daily transpiration; in contrast, only 0.5–2.0 kg day −1 was withdrawn in ring-porous Fraxinus. Wood density had a large influence on storage; sapwood area (diffuse- vs. ringporous) may be another influential factor but its effect was not significant. Across the five species, the length of the time lag in flow at stem top and stem base was positively related to the size of stem storage. The stem stores were mostly exhausted when the soil matrix potential dropped below −0.1 MPa and daily mean vapor pressure deficit exceeded 3–5 hPa. We conclude that stem storage is an important factor improving the water balance of diffuse-porous temperate Broad-Leaved Trees in moist periods, while it may be of low relevance in dry periods and in ring-porous species.
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environmental control of daily stem growth patterns in five temperate broad leaved Tree species
Tree Physiology, 2012Co-Authors: Paul Kocher, Viviana Horna, Christoph LeuschnerAbstract:Tree ring analysis investigates growth processes at time horizons of several weeks to millennia, but lacks the detail of shortterm fluctuation in cambial activity. This study used electronic high-precision dendrometry for analyzing the environmental factors controlling stem diameter variation and radial growth in daily resolution in five co-existing temperate Broad-Leaved Tree species (genera Fraxinus, Acer, Carpinus, Tilia and Fagus) with different growth and survival strategies. Daily stem radius change (SRCd) was primarily influenced by the atmospheric demand for water vapor (expressed either as vapor pressure defi cit (D) or relative air humidity (RH)) while rainfall, soil matrix potential, temperature and radiation were only secondary factors. SRCd increased linearly with increasing RH and decreasing D in all species. The positive effect of a low atmospheric water vapor demand on SRCd was largest in June during the period of maximal radial growth rate and persisted when observation windows of 7 or 21 days instead of 1 day were used. We found a high synchronicity in the day-to-day growth rate fluctuation among the species with increment peaks corresponding to air humidity maxima, even though the mean daily radial growth rate differed fivefold among the species. The five species also differed in the positive slope of the growth/RH relationship with the steepest increase found in Fraxinus and the lowest in Fagus. We explain the strong positive effect of high RH and low D on radial stem increment by lowered transpiration which reduces negative pressure in the conducting system and increases turgor in the stem cambium cells, thereby favoring cell division and expansion. The results suggest that mechanistic models of Tree growth need to consider the atmospheric water status in addition to the known controlling environmental factors: temperature, soil moisture and precipitation. The results further have implications for sensitivity analyses of Tree growth to climatic changes.
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leaf water status and stem xylem flux in relation to soil drought in five temperate broad leaved Tree species with contrasting water use strategies
Annals of Forest Science, 2009Co-Authors: Paul Kocher, Viviana Horna, Tobias Gebauer, Christoph LeuschnerAbstract:• Five temperate Broad-Leaved Tree species were compared with respect to their water consumption strategies under ample and restricted water supply. We measured synchronously leaf conductance (gL) in the sun canopy, xylem sap flux (Js) and leaf water potential (predawn, Ψpd and noon, Ψnoon) in adult Trees in a mixed stand and related them to the fluctuations in vapor pressure deficit (D )a nd soil moisture. • Maximum gL was particularly high in F. excelsior, C. betulus and T. cordata and revealed a higher D sensitivity. Ψpd remained constantly high in A. pseudoplatanus, C. betulus and F. excelsior ,b ut decreased in T. cordata and F. sylvatica with decreasing soil moisture. • Jsd decreased linearly with decreasing soil matrix potential in all species except for F. excelsior. Apparent hydraulic conductance in the soil-to-leaf flow path (Lc) was higher in A. pseudoplatanus than in the other species. • F. sylvatica maintained a low maximum gL and reduced Jsd markedly upon drought, but faced severe decreases in Ψpd and Ψnoon. F. excelsior represents an opposite strategy with high maximum gL and stable Ψpd. • The species drought sensitivity increases in the sequence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica.
Paul Kocher - One of the best experts on this subject based on the ideXlab platform.
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stem water storage in five coexisting temperate broad leaved Tree species significance temporal dynamics and dependence on Tree functional traits
Tree Physiology, 2013Co-Authors: Paul Kocher, Viviana Horna, Christoph LeuschnerAbstract:The functional role of internal water storage is increasingly well understood in tropical Trees and conifers, while temperate Broad-Leaved Trees have only rarely been studied. We examined the magnitude and dynamics of the use of stem water reserves for transpiration in five coexisting temperate Broad-Leaved Trees with largely different morphology and physiology (genera Fagus, Fraxinus, Tilia, Carpinus and Acer). We expected that differences in water storage patterns would mostly reflect species differences in wood anatomy (ring vs. diffuse-porous) and wood density. Sap flux density was recorded synchronously at five positions along the root-to-branch flow path of mature Trees (roots, three stem positions and branches) with high temporal resolution (2 min) and related to stem radius changes recorded with electronic point dendrometers. The daily amount of stored stem water withdrawn for transpiration was estimated by comparing the integrated flow at stem base and stem top. The tem poral coincidence of flows at different positions and apparent time lags were examined by cross- correlation analysis. Our results confirm that internal water stores play an important role in the four diffuse-porous species with estimated 5–12 kg day −1 being withdrawn on average in 25–28 m tall Trees representing 10–22% of daily transpiration; in contrast, only 0.5–2.0 kg day −1 was withdrawn in ring-porous Fraxinus. Wood density had a large influence on storage; sapwood area (diffuse- vs. ringporous) may be another influential factor but its effect was not significant. Across the five species, the length of the time lag in flow at stem top and stem base was positively related to the size of stem storage. The stem stores were mostly exhausted when the soil matrix potential dropped below −0.1 MPa and daily mean vapor pressure deficit exceeded 3–5 hPa. We conclude that stem storage is an important factor improving the water balance of diffuse-porous temperate Broad-Leaved Trees in moist periods, while it may be of low relevance in dry periods and in ring-porous species.
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environmental control of daily stem growth patterns in five temperate broad leaved Tree species
Tree Physiology, 2012Co-Authors: Paul Kocher, Viviana Horna, Christoph LeuschnerAbstract:Tree ring analysis investigates growth processes at time horizons of several weeks to millennia, but lacks the detail of shortterm fluctuation in cambial activity. This study used electronic high-precision dendrometry for analyzing the environmental factors controlling stem diameter variation and radial growth in daily resolution in five co-existing temperate Broad-Leaved Tree species (genera Fraxinus, Acer, Carpinus, Tilia and Fagus) with different growth and survival strategies. Daily stem radius change (SRCd) was primarily influenced by the atmospheric demand for water vapor (expressed either as vapor pressure defi cit (D) or relative air humidity (RH)) while rainfall, soil matrix potential, temperature and radiation were only secondary factors. SRCd increased linearly with increasing RH and decreasing D in all species. The positive effect of a low atmospheric water vapor demand on SRCd was largest in June during the period of maximal radial growth rate and persisted when observation windows of 7 or 21 days instead of 1 day were used. We found a high synchronicity in the day-to-day growth rate fluctuation among the species with increment peaks corresponding to air humidity maxima, even though the mean daily radial growth rate differed fivefold among the species. The five species also differed in the positive slope of the growth/RH relationship with the steepest increase found in Fraxinus and the lowest in Fagus. We explain the strong positive effect of high RH and low D on radial stem increment by lowered transpiration which reduces negative pressure in the conducting system and increases turgor in the stem cambium cells, thereby favoring cell division and expansion. The results suggest that mechanistic models of Tree growth need to consider the atmospheric water status in addition to the known controlling environmental factors: temperature, soil moisture and precipitation. The results further have implications for sensitivity analyses of Tree growth to climatic changes.
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leaf water status and stem xylem flux in relation to soil drought in five temperate broad leaved Tree species with contrasting water use strategies
Annals of Forest Science, 2009Co-Authors: Paul Kocher, Viviana Horna, Tobias Gebauer, Christoph LeuschnerAbstract:• Five temperate Broad-Leaved Tree species were compared with respect to their water consumption strategies under ample and restricted water supply. We measured synchronously leaf conductance (gL) in the sun canopy, xylem sap flux (Js) and leaf water potential (predawn, Ψpd and noon, Ψnoon) in adult Trees in a mixed stand and related them to the fluctuations in vapor pressure deficit (D )a nd soil moisture. • Maximum gL was particularly high in F. excelsior, C. betulus and T. cordata and revealed a higher D sensitivity. Ψpd remained constantly high in A. pseudoplatanus, C. betulus and F. excelsior ,b ut decreased in T. cordata and F. sylvatica with decreasing soil moisture. • Jsd decreased linearly with decreasing soil matrix potential in all species except for F. excelsior. Apparent hydraulic conductance in the soil-to-leaf flow path (Lc) was higher in A. pseudoplatanus than in the other species. • F. sylvatica maintained a low maximum gL and reduced Jsd markedly upon drought, but faced severe decreases in Ψpd and Ψnoon. F. excelsior represents an opposite strategy with high maximum gL and stable Ψpd. • The species drought sensitivity increases in the sequence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica.
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Leaf water status and stem xylem flux in relation to soil drought in five temperate Broad-Leaved Tree species with contrasting water use strategies
Annals of Forest Science, 2009Co-Authors: Paul Kocher, Viviana Horna, Tobias Gebauer, Christoph LeuschnerAbstract:• Les stratégies de consommation d’eau de cinq espèces d’arbres feuillus tempérés ont été comparées sous approvisionnement en eau suffisant ou limité. De façon synchrone nous avons mesuré la conductance hydraulique des feuilles ( g _L) dans la partie du couvert exposée au soleil, le flux de sève xylémique ( J _s) et le potentiel hydrique foliaire (potentiel de base (ψ_pd) et potentiel minimum (ψ_noon)) d’arbres adultes en peuplement mixte et nous les avons reliés aux fluctuations du déficit de pression de vapeur ( D ) et à l’humidité du sol. • g _L maximum était particulièrement élevée chez F. excelsior, C. betulus et T. cordata et a révélé une plus grande sensibilité à D. ψ_pd est resté constamment élevé chez A. pseudoplatanus, C. betulus et F. excelsior , mais a diminué chez T. cordata et F. sylvatica lorsque l’humidité du sol diminuait. • J _sd a diminué linéairement avec le potentiel matriciel du sol pour toutes les espèces excepté F. excelsior . La conductivité hydraulique apparente du trajet sol-feuille ( L _c) était plus élevée chez A. pseudoplatanus que dans les autres espèces. • F. sylvatica a maintenu une faible g _L maximum et a réduit sensiblement J _sd face à la sécheresse, mais a connu de graves diminutions de ψ_pd et ψ_noon. F. excelsior présentait une stratégie opposée avec une g _L maximum élevée et un ψ_pd stable. • La sensibilité des espèces à la sécheresse augmente selon la séquence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica . • Five temperate Broad-Leaved Tree species were compared with respect to their water consumption strategies under ample and restricted water supply. We measured synchronously leaf conductance ( g _L) in the sun canopy, xylem sap flux ( J _s) and leaf water potential (predawn, ψ_pd and noon, ψ_noon) in adult Trees in a mixed stand and related them to the fluctuations in vapor pressure deficit ( D ) and soil moisture. • Maximum g _L was particularly high in F. excelsior, C. betulus and T. cordata and revealed a higher D sensitivity. ψ_pd remained constantly high in A. pseudoplatanus, C. betulus and F. excelsior , but decreased in T. cordata and F. sylvatica with decreasing soil moisture. • J _sddecreased linearly with decreasing soil matrix potential in all species except for F. excelsior . Apparent hydraulic conductance in the soil-to-leaf flow path ( L _c) was higher in A. pseudoplatanus than in the other species. • F. sylvatica maintained a low maximum g _L and reduced J _sd markedly upon drought, but faced severe decreases in ψ_pd and ψ_noon. F. excelsior represents an opposite strategy with high maximum g _L and stable ψ_pd. • The species drought sensitivity increases in the sequence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica .
Viviana Horna - One of the best experts on this subject based on the ideXlab platform.
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stem water storage in five coexisting temperate broad leaved Tree species significance temporal dynamics and dependence on Tree functional traits
Tree Physiology, 2013Co-Authors: Paul Kocher, Viviana Horna, Christoph LeuschnerAbstract:The functional role of internal water storage is increasingly well understood in tropical Trees and conifers, while temperate Broad-Leaved Trees have only rarely been studied. We examined the magnitude and dynamics of the use of stem water reserves for transpiration in five coexisting temperate Broad-Leaved Trees with largely different morphology and physiology (genera Fagus, Fraxinus, Tilia, Carpinus and Acer). We expected that differences in water storage patterns would mostly reflect species differences in wood anatomy (ring vs. diffuse-porous) and wood density. Sap flux density was recorded synchronously at five positions along the root-to-branch flow path of mature Trees (roots, three stem positions and branches) with high temporal resolution (2 min) and related to stem radius changes recorded with electronic point dendrometers. The daily amount of stored stem water withdrawn for transpiration was estimated by comparing the integrated flow at stem base and stem top. The tem poral coincidence of flows at different positions and apparent time lags were examined by cross- correlation analysis. Our results confirm that internal water stores play an important role in the four diffuse-porous species with estimated 5–12 kg day −1 being withdrawn on average in 25–28 m tall Trees representing 10–22% of daily transpiration; in contrast, only 0.5–2.0 kg day −1 was withdrawn in ring-porous Fraxinus. Wood density had a large influence on storage; sapwood area (diffuse- vs. ringporous) may be another influential factor but its effect was not significant. Across the five species, the length of the time lag in flow at stem top and stem base was positively related to the size of stem storage. The stem stores were mostly exhausted when the soil matrix potential dropped below −0.1 MPa and daily mean vapor pressure deficit exceeded 3–5 hPa. We conclude that stem storage is an important factor improving the water balance of diffuse-porous temperate Broad-Leaved Trees in moist periods, while it may be of low relevance in dry periods and in ring-porous species.
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environmental control of daily stem growth patterns in five temperate broad leaved Tree species
Tree Physiology, 2012Co-Authors: Paul Kocher, Viviana Horna, Christoph LeuschnerAbstract:Tree ring analysis investigates growth processes at time horizons of several weeks to millennia, but lacks the detail of shortterm fluctuation in cambial activity. This study used electronic high-precision dendrometry for analyzing the environmental factors controlling stem diameter variation and radial growth in daily resolution in five co-existing temperate Broad-Leaved Tree species (genera Fraxinus, Acer, Carpinus, Tilia and Fagus) with different growth and survival strategies. Daily stem radius change (SRCd) was primarily influenced by the atmospheric demand for water vapor (expressed either as vapor pressure defi cit (D) or relative air humidity (RH)) while rainfall, soil matrix potential, temperature and radiation were only secondary factors. SRCd increased linearly with increasing RH and decreasing D in all species. The positive effect of a low atmospheric water vapor demand on SRCd was largest in June during the period of maximal radial growth rate and persisted when observation windows of 7 or 21 days instead of 1 day were used. We found a high synchronicity in the day-to-day growth rate fluctuation among the species with increment peaks corresponding to air humidity maxima, even though the mean daily radial growth rate differed fivefold among the species. The five species also differed in the positive slope of the growth/RH relationship with the steepest increase found in Fraxinus and the lowest in Fagus. We explain the strong positive effect of high RH and low D on radial stem increment by lowered transpiration which reduces negative pressure in the conducting system and increases turgor in the stem cambium cells, thereby favoring cell division and expansion. The results suggest that mechanistic models of Tree growth need to consider the atmospheric water status in addition to the known controlling environmental factors: temperature, soil moisture and precipitation. The results further have implications for sensitivity analyses of Tree growth to climatic changes.
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leaf water status and stem xylem flux in relation to soil drought in five temperate broad leaved Tree species with contrasting water use strategies
Annals of Forest Science, 2009Co-Authors: Paul Kocher, Viviana Horna, Tobias Gebauer, Christoph LeuschnerAbstract:• Five temperate Broad-Leaved Tree species were compared with respect to their water consumption strategies under ample and restricted water supply. We measured synchronously leaf conductance (gL) in the sun canopy, xylem sap flux (Js) and leaf water potential (predawn, Ψpd and noon, Ψnoon) in adult Trees in a mixed stand and related them to the fluctuations in vapor pressure deficit (D )a nd soil moisture. • Maximum gL was particularly high in F. excelsior, C. betulus and T. cordata and revealed a higher D sensitivity. Ψpd remained constantly high in A. pseudoplatanus, C. betulus and F. excelsior ,b ut decreased in T. cordata and F. sylvatica with decreasing soil moisture. • Jsd decreased linearly with decreasing soil matrix potential in all species except for F. excelsior. Apparent hydraulic conductance in the soil-to-leaf flow path (Lc) was higher in A. pseudoplatanus than in the other species. • F. sylvatica maintained a low maximum gL and reduced Jsd markedly upon drought, but faced severe decreases in Ψpd and Ψnoon. F. excelsior represents an opposite strategy with high maximum gL and stable Ψpd. • The species drought sensitivity increases in the sequence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica.
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Leaf water status and stem xylem flux in relation to soil drought in five temperate Broad-Leaved Tree species with contrasting water use strategies
Annals of Forest Science, 2009Co-Authors: Paul Kocher, Viviana Horna, Tobias Gebauer, Christoph LeuschnerAbstract:• Les stratégies de consommation d’eau de cinq espèces d’arbres feuillus tempérés ont été comparées sous approvisionnement en eau suffisant ou limité. De façon synchrone nous avons mesuré la conductance hydraulique des feuilles ( g _L) dans la partie du couvert exposée au soleil, le flux de sève xylémique ( J _s) et le potentiel hydrique foliaire (potentiel de base (ψ_pd) et potentiel minimum (ψ_noon)) d’arbres adultes en peuplement mixte et nous les avons reliés aux fluctuations du déficit de pression de vapeur ( D ) et à l’humidité du sol. • g _L maximum était particulièrement élevée chez F. excelsior, C. betulus et T. cordata et a révélé une plus grande sensibilité à D. ψ_pd est resté constamment élevé chez A. pseudoplatanus, C. betulus et F. excelsior , mais a diminué chez T. cordata et F. sylvatica lorsque l’humidité du sol diminuait. • J _sd a diminué linéairement avec le potentiel matriciel du sol pour toutes les espèces excepté F. excelsior . La conductivité hydraulique apparente du trajet sol-feuille ( L _c) était plus élevée chez A. pseudoplatanus que dans les autres espèces. • F. sylvatica a maintenu une faible g _L maximum et a réduit sensiblement J _sd face à la sécheresse, mais a connu de graves diminutions de ψ_pd et ψ_noon. F. excelsior présentait une stratégie opposée avec une g _L maximum élevée et un ψ_pd stable. • La sensibilité des espèces à la sécheresse augmente selon la séquence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica . • Five temperate Broad-Leaved Tree species were compared with respect to their water consumption strategies under ample and restricted water supply. We measured synchronously leaf conductance ( g _L) in the sun canopy, xylem sap flux ( J _s) and leaf water potential (predawn, ψ_pd and noon, ψ_noon) in adult Trees in a mixed stand and related them to the fluctuations in vapor pressure deficit ( D ) and soil moisture. • Maximum g _L was particularly high in F. excelsior, C. betulus and T. cordata and revealed a higher D sensitivity. ψ_pd remained constantly high in A. pseudoplatanus, C. betulus and F. excelsior , but decreased in T. cordata and F. sylvatica with decreasing soil moisture. • J _sddecreased linearly with decreasing soil matrix potential in all species except for F. excelsior . Apparent hydraulic conductance in the soil-to-leaf flow path ( L _c) was higher in A. pseudoplatanus than in the other species. • F. sylvatica maintained a low maximum g _L and reduced J _sd markedly upon drought, but faced severe decreases in ψ_pd and ψ_noon. F. excelsior represents an opposite strategy with high maximum g _L and stable ψ_pd. • The species drought sensitivity increases in the sequence F. excelsior < C. betulus < T. cordata < A. pseudoplatanus < F. sylvatica .
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variability in radial sap flux density patterns and sapwood area among seven co occurring temperate broad leaved Tree species
Tree Physiology, 2008Co-Authors: Tobias Gebauer, Viviana Horna, Christoph LeuschnerAbstract:Forest transpiration estimates are frequently based on xylem sap flux measurements in the outer sections of the hydro-active stem sapwood. We used Granier's constant-heating technique with heating probes at various xylem depths to analyze radial patterns of sap flux density in the sapwood of seven Broad-Leaved Tree species differing in wood density and xylem structure. Study aims were to (1) compare radial sap flux density profiles between diffuse- and ring-porous Trees and (2) analyze the relationship between hydro-active sapwood area and stem diameter. In all investigated species except the diffuse-porous beech (Fagus sylvatica L.) and ring-porous ash (Fraxinus excelsior L.), sap flux density peaked at a depth of 1 to 4 cm beneath the cambium, revealing a hump-shaped curve with species-specific slopes. Beech and ash reached maximum sap flux densities immediately beneath the cambium in the youngest annual growth rings. Experiments with dyes showed that the hydro-active sapwood occupied 70 to 90% of the stem cross-sectional area in mature Trees of diffuse-porous species, whereas it occupied only about 21% in ring-porous ash. Dendrochronological analyses indicated that vessels in the older sapwood may remain functional for 100 years or more in diffuse-porous species and for up to 27 years in ring-porous ash. We conclude that radial sap flux density patterns are largely dependent on Tree species, which may introduce serious bias in sap-flux-derived forest transpiration estimates, if non-specific sap flux profiles are assumed.
Kenji Seiwa - One of the best experts on this subject based on the ideXlab platform.
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Carbon allocation to defense, storage, and growth in seedlings of two temperate Broad-Leaved Tree species
Oecologia, 2010Co-Authors: Aya Imaji, Kenji SeiwaAbstract:Optimal carbon allocation to growth, defense, or storage is a critical trait in determining the shade tolerance of Tree species. Thus, examining interspecific differences in carbon allocation patterns is useful when evaluating niche partitioning in forest communities. We hypothesized that shade-tolerant species allocate more carbon to defense and storage and less to growth compared to shade-intolerant species. In gaps and forest understory, we measured relative growth rates (RGR), carbon-based defensive compounds (condensed tannin, total phenolics), and storage compounds (total non-structural carbohydrate; TNC) in seedlings of two Tree species differing in shade tolerance. RGR was greater in the shade-intolerant species, Castanea crenata , than in the shade-tolerant species, Quercus mongolica var. grosseserrata , in gaps, but did not differ between the species in the forest understory. In contrast, concentrations of condensed tannin and total phenolics were greater in Quercus than in Castanea at both sites. TNC pool sizes did not differ between the species. Condensed tannin concentrations increased with increasing growth rate of structural biomass (GRstr) in Quercus but not in Castanea . TNC pool sizes increased with increasing GRstr in both species, but the rate of increase did not differ between the species. Accordingly, the amount of condensed tannin against TNC pool sizes was usually higher in Quercus than in Castanea . Hence, Quercus preferentially invested more carbon in defense than in storage. Such a large allocation of carbon to defense would be advantageous for a shade-tolerant species, allowing Quercus to persist in the forest understory where damage from herbivores and pathogens is costly. In contrast, the shade-intolerant Castanea preferentially invested more carbon in growth rather than defense (and similar amounts in storage as Quercus ), ensuring establishment success in gaps, where severe competition occurs for light among neighboring plants. These contrasting carbon allocation patterns are closely associated with strategies for persistence in these species’ respective habitats.
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Ontogenetic changes in leaf phenology of Ulmus davidiana var. japonica, a deciduous Broad-Leaved Tree.
Tree Physiology, 1999Co-Authors: Kenji SeiwaAbstract:: To determine how plants control leaf phenology to maximize annual carbon gain, I examined ontogenetic changes in leaf phenology of Japanese elm, Ulmus davidiana var. japonica Nakai plants of different ages growing in contrasting light environments. Leaf emergence occurred earlier in 1- and 2-year-old seedlings than in current-year seedlings. Although leaf emergence was not affected by light conditions at the sites, it was influenced by plant height. The delay in leaf emergence increased with increasing plant height. These traits indicate that seedlings that received the least light during the summer intercepted light for a long period during the spring; however, the advantage of earlier leaf emergence decreased with increasing plant height. At each site, 1-year-old seedlings had a longer duration of leaf emergence than adults, because of a longer period of favorable light conditions even in the forest understory. Duration of leaf emergence, leaf duration and leaf longevity were usually longer in sun than in shade for both seedlings and adults; however, flexibility in the response to light was greater in seedlings than in adults. The plastic response in leaf phenology during the juvenile stages may contribute to the optimization of light acquisition in habitats with differing light conditions, thereby enhancing seedling survival.
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Changes in Leaf Phenology are Dependent on Tree Height inAcer mono, a Deciduous Broad-Leaved Tree
Annals of Botany, 1999Co-Authors: Kenji SeiwaAbstract:Ontogenetic changes in leaf phenology of a hardwood Tree,Acer mono, were investigated in individuals in different size classes in a temperate forest. Leaf emergence was earliest in current-year seedlings, and was increasingly delayed with increasing height of the individual. The shorter the Tree, the longer the duration of leaf emergence. Timing of leaf emergence of the dominant heterospecific canopy Trees was almost identical to that of conspecific adults; understorey light then gradually decreased with expansion of canopy leaves. These traits indicate that smaller individuals that receive the least light in summer can acquire favourable light for a longer period in spring than taller plants even in a forest understorey, but the advantage decreases with increasing plant height. Changes in the duration of leaf emergence and leaf longevity in response to environmental light regime [sun (forest edge)vs. shade (forest understorey)], were greatest for current year seedlings but decreased with increasing plant height. These results suggest that the plastic response of leaf phenology in juvenile stages may reduce the risk of losing an entire cohort in spatially heterogenous environments in the understorey of temperate forests.
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importance of seed size for the establishment of seedlings of five deciduous broad leaved Tree species
Plant Ecology, 1996Co-Authors: Kenji Seiwa, Kihachiro KikuzawaAbstract:Effects of seed size and phenology on the establishment of five deciduous Broad-Leaved Tree species were examined in deciduous woodland. Treatments included absence and presence of litter in the forest understory, a small gap, and a large gap. Seedling emergence of large-seeded speciesQuercus mongolica var.grosseserrata andAcer mono was not reduced by accumulation of litter in the forest understory, but was promoted in the large gap where litter was less. Seedling emergence of small-seeded species,Alnus hirsuta, Cercidiphyllum japonicum andBetula platyphylla var.japonica, was reduced by the litter in almost all of the sites. Seedlings of large-seeded species avoid shade stress phenologically by unfolding all of their large leaves in a short period before canopy closure in the forest understory. These species had little mortality after seedling emergence. In contrast, small-seeded species have a longer duration of leaf emergence, shorter leaf longevity, and rapid leaf turnover in all the sites. These seedlings attained similar height to those of the large-seeded species at the end of the second year in the large gap, but survival and height growth rate decreased after canopy closure in the forest understory. We suggest that the importance of seed size in determining seedling establishment largely depends on the relationships between seasonal changes of environmental conditions and phenological traits of seedlings, which are related to seed size.
Ichiro Terashima - One of the best experts on this subject based on the ideXlab platform.
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Slow development of leaf photosynthesis in an evergreen broad‐leaved Tree, Castanopsis sieboldii: relationships between leaf anatomical characteristics and photosynthetic rate
Plant Cell & Environment, 2001Co-Authors: Shin-ichi Miyazawa, Ichiro TerashimaAbstract:Changes in net photosynthetic rate on a leaf area basis and anatomical properties during leaf development were studied in an evergreen Broad-Leaved Tree, Castanopsis sieboldii and an annual herb, Phaseolus vulgaris. In C. sieboldii, surface area of mesophyll cells facing the intercellular air spaces on a leaf area basis (S mes ) was already considerable at the time of full leaf area expansion (FLE). However, surface area of chloroplasts facing the intercellular air spaces on a leaf area basis (S c ), and chlorophyll and Rubisco contents on a leaf area basis increased to attain their maximal values 15-40 d after FLE. In contrast, in P. vulgaris, chloroplast number on a leaf area basis, S c and S mes at 10 d before FLE were two to three times greater than the steady-state levels attained at around FLE. In C. sieboldii, the internal CO 2 transfer conductance (g i ) slightly increased for 10 d after FLE but then decreased toward the later stages. Limitation of photosynthesis by g i was only about 10% at FLE, but then increased to about 30% at around 40 d after FLE. The large limitation after FLE by g i was probably due to the decrease in CO 2 concentration in the chloroplast caused by the increases in thickness of mesophyll cell walls and in Rubisco content per chloroplast surface area. These results clearly showed that: (1) in C. sieboldii, chloroplast development proceeded more slowly than mesophyll cell expansion and continued well after FLE, whereas in P. vulgaris these processes proceeded synchronously and were completed by FLE; (2) after FLE, photosynthesis in leaves of C. sieboldii was markedly limited by g i . From these results, it is suggested that, in the evergreen Broad-Leaved Trees, mechanical protection of mesophyll cells has priority over the efficient CO 2 transfer and quick construction of the chloroplasts.
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slow development of leaf photosynthesis in an evergreen broad leaved Tree castanopsis sieboldii relationships between leaf anatomical characteristics and photosynthetic rate
Plant Cell and Environment, 2001Co-Authors: Shin-ichi Miyazawa, Ichiro TerashimaAbstract:Changes in net photosynthetic rate on a leaf area basis and anatomical properties during leaf development were studied in an evergreen Broad-Leaved Tree, Castanopsis sieboldii and an annual herb, Phaseolus vulgaris. In C. sieboldii, surface area of mesophyll cells facing the intercellular air spaces on a leaf area basis (S mes ) was already considerable at the time of full leaf area expansion (FLE). However, surface area of chloroplasts facing the intercellular air spaces on a leaf area basis (S c ), and chlorophyll and Rubisco contents on a leaf area basis increased to attain their maximal values 15-40 d after FLE. In contrast, in P. vulgaris, chloroplast number on a leaf area basis, S c and S mes at 10 d before FLE were two to three times greater than the steady-state levels attained at around FLE. In C. sieboldii, the internal CO 2 transfer conductance (g i ) slightly increased for 10 d after FLE but then decreased toward the later stages. Limitation of photosynthesis by g i was only about 10% at FLE, but then increased to about 30% at around 40 d after FLE. The large limitation after FLE by g i was probably due to the decrease in CO 2 concentration in the chloroplast caused by the increases in thickness of mesophyll cell walls and in Rubisco content per chloroplast surface area. These results clearly showed that: (1) in C. sieboldii, chloroplast development proceeded more slowly than mesophyll cell expansion and continued well after FLE, whereas in P. vulgaris these processes proceeded synchronously and were completed by FLE; (2) after FLE, photosynthesis in leaves of C. sieboldii was markedly limited by g i . From these results, it is suggested that, in the evergreen Broad-Leaved Trees, mechanical protection of mesophyll cells has priority over the efficient CO 2 transfer and quick construction of the chloroplasts.
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SLOW LEAF DEVELOPMENT OF EVERGREEN Broad-Leaved Tree SPECIES IN JAPANESE WARM TEMPERATE FORESTS
Annals of Botany, 1998Co-Authors: Shin-ichi Miyazawa, Shigenari Satomi, Ichiro TerashimaAbstract:Rates of light-saturated net photosynthesis (P N max) and dark respiration (Rd) on a leaf area basis, leaf dry mass per area (LMA), leaf nitrogen content on a leaf area basis (LNa) and instantaneous nitrogen use eciency (NUE fl P N max}LNa) were followed during leaf development in six evergreen Broad-Leaved Tree species typical of warmtemperate forests in Japan. These species were Castanopsis sieboldii, Quercus myrsinaefolia, Quercus glauca, Machilus thunbergii, Cinnamomum japonicum and Neolitsea sericea. When expansion of leaf area was complete, P N max was about one third of its peak value and increased for another 15 to 44 d. Rd at full leaf expansion was about 1‐ 5t o 3‐5times greater than steady-state rates. These facts suggest that leaf development was still underway at the time of full leaf area expansion. Low P N max at full leaf expansion was caused both by low leaf nitrogen content and low NUE. P N max increased with the increase in LMA during leaf development in all six species; data from the literature for other species with dierent life forms also indicated a similar tendency. The steady-state LMA varied markedly among species. Because leaves with larger steady-state LMAs need more resources for their construction, they will also need longer periods for maturation. We hypothesized that the period required for the attainment of peak P N max, the ‘leaf maturation period’, depends on the steady-state LMA. Plotting data from the present study together with those from literature for other plants across several life forms showed a strong positive relationship between leaf maturation period and steady-state LMA, supporting the hypothesis. # 1998 Annals of Botany Company
