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Pubblicazioni Scientifiche
Filtri di ricerca 6 risultati
Pubblicazioni per anno
Forest structure and understory functional diversity at multiple scales: The importance of median tree height
de Benedictis
,
Luciano Ludovico Maria
,
Chelli
,
Stefano
,
Zhu
,
Zhengxue
,
Cervellini
,
Marco
,
Canullo
,
R.
,
Chianucci
,
Francesco
,
Puletti
,
Nicola
,
Tsakalos
,
James L.
,
Bartha
,
Sándor
,
Campetella
,
Giandiego
The Relationship Between Maturation Size and Maximum Tree Size From Tropical to Boreal Climates
Journé
,
Valentin
,
Bogdziewicz
,
Michał
,
Courbaud
,
Benoít
,
Kunstler
,
Georges
,
Qiu
,
Tong
,
Aravena Acuña
,
Marie Claire
,
Ascoli
,
Davide
,
Bergeron
,
Yves
,
Berveiller
,
Daniel
,
Boivin
,
Thomas
,
Bonal
,
Raúl
,
Caignard
,
Thomas
,
Cailleret
,
Maxime
,
Calama
,
Rafael A.
,
Camarero
,
Jesús Julio
,
Chang-Yang
,
Chia Hao
,
Chave
,
Jérôme
,
Chianucci
,
Francesco
,
Curt
,
Thomas
,
Cutini
,
Andrea
,
Das
,
Adrian J.
,
Daskalakou
,
Evangelia N.
,
Davi
,
Hendrik
,
Delpierre
,
Nicolas
,
Delzon
,
Sylvain
,
Dietze
,
Michael C.
,
Calderon
,
Sergio Donoso
,
Dormont
,
Laurent
,
Espelta
,
Josep Maria
,
Farfan-Rios
,
William R.
,
Fenner
,
Michael
,
Franklin
,
Jerry F.
,
Gehring
,
Catherine A.
,
Gilbert
,
Gregory S.
,
Gratzer
,
Georg
,
Greenberg
,
Cathryn H.
,
Guignabert
,
Arthur
,
Guo
,
Qinfeng
,
Hacket-Pain
,
Andrew J.
,
Hampe
,
Arndt
,
Han
,
Qingmin
,
Hanley
,
Mick E.
,
Hille Ris Lambers
,
Janneke
,
Holik
,
Jan
,
Hoshizaki
,
K.
,
Ibáñez
,
Inés
,
Johnstone
,
Jill F.
,
Knops
,
Johannes Michael Hubertus
,
Kobe
,
Richard K.
,
Kurokawa
,
Hiroko
,
Lageard
,
Jonathan G.A.
,
LaMontagne
,
Jalene M.
,
Ledwoń
,
Mateusz
,
Lefèvre
,
François
,
Leininger
,
Theodor D.
,
Limousin
,
Jean Marc
,
Lutz
,
James A.
,
Macias
,
Diana S.
,
Mårell
,
Anders
,
McIntire
,
Eliot J.B.
,
Moran
,
Emily V.
,
Motta
,
Renzo
,
Myers
,
Jonathan A.
,
Nagel
,
Thomas A.
,
Naoe
,
Shoji
,
Noguchi
,
Mahoko
,
Norghauer
,
Julian M.
,
Oguro
,
Michio
,
Ourcival
,
Jean Marc
,
Parmenter
,
Robert R.
,
Pearse
,
Ian S.
,
Pérez-Ramos
,
Ignacio M.
,
Piechnik
,
Łukasz
,
Podgórski
,
Tomasz
,
Poulsen
,
John R.
,
Redmond
,
Miranda D.
,
Reid
,
Chantal D.
,
Šamonil
,
Pavel
,
Scher
,
C. Lane
,
Schlesinger
,
William H.
,
Seget
,
Barbara
,
Sharma
,
Shubhi
,
Shibata
,
Mitsue
,
Silman
,
Miles R.
,
Steele
,
Michael A.
,
Stephenson
,
Nathan L.
,
Straub
,
Jacob N.
,
Sutton
,
Samantha
,
Swenson
,
Jennifer J.
,
Swift
,
Margaret
,
Thomas
,
Peter A.
,
Uríarte
,
María
,
Vacchiano
,
Giorgio
,
Whipple
,
Amy Vaughn
,
Whitham
,
Thomas G.
,
Wright
,
Stuart Joseph
,
Zhu
,
Kai
,
Zimmerman
,
Jess K.
,
Żywiec
,
Magdalena
,
Clark
,
James S.
Mostra abstract
The fundamental trade-off between current and future reproduction has long been considered to result in a tendency for species that can grow large to begin reproduction at a larger size. Due to the prolonged time required to reach maturity, estimates of tree maturation size remain very rare and we lack a global view on the generality and the shape of this trade-off. Using seed production from five continents, we estimate tree maturation sizes for 486 tree species spanning tropical to boreal climates. Results show that a species' maturation size increases with maximum size, but in a non-proportional way: the largest species begin reproduction at smaller sizes than would be expected if maturation were simply proportional to maximum size. Furthermore, the decrease in relative maturation size is steepest in cold climates. These findings on maturation size drivers are key to accurately represent forests' responses to disturbance and climate change. © 2024 John Wiley & Sons Ltd.
Masting is uncommon in trees that depend on mutualist dispersers in the context of global climate and fertility gradients
Qiu
,
Tong
,
Aravena Acuña
,
Marie Claire
,
Ascoli
,
Davide
,
Bergeron
,
Yves
,
Bogdziewicz
,
Michał
,
Boivin
,
Thomas
,
Bonal
,
Raúl
,
Caignard
,
Thomas
,
Cailleret
,
Maxime
,
Calama
,
Rafael A.
,
Calderon
,
Sergio Donoso
,
Camarero
,
Jesús Julio
,
Chang-Yang
,
Chia Hao
,
Chave
,
Jérôme
,
Chianucci
,
Francesco
,
Courbaud
,
Benoít
,
Cutini
,
Andrea
,
Das
,
Adrian J.
,
Delpierre
,
Nicolas
,
Delzon
,
Sylvain
,
Dietze
,
Michael C.
,
Dormont
,
Laurent
,
Espelta
,
Josep Maria
,
Fahey
,
Timothy J.
,
Farfan-Rios
,
William R.
,
Franklin
,
Jerry F.
,
Gehring
,
Catherine A.
,
Gilbert
,
Gregory S.
,
Gratzer
,
Georg
,
Greenberg
,
Cathryn H.
,
Guignabert
,
Arthur
,
Guo
,
Qinfeng
,
Hacket-Pain
,
Andrew J.
,
Hampe
,
Arndt
,
Han
,
Qingmin
,
Holik
,
Jan
,
Hoshizaki
,
K.
,
Ibáñez
,
Inés
,
Johnstone
,
Jill F.
,
Journé
,
Valentin
,
Kitzberger
,
Thomas A.
,
Knops
,
Johannes Michael Hubertus
,
Kunstler
,
Georges
,
Kurokawa
,
Hiroko
,
Lageard
,
Jonathan G.A.
,
LaMontagne
,
Jalene M.
,
Lefèvre
,
François
,
Leininger
,
Theodor D.
,
Limousin
,
Jean Marc
,
Lutz
,
James A.
,
Macias
,
Diana S.
,
Mårell
,
Anders
,
McIntire
,
Eliot J.B.
,
Moore
,
Christopher M.
,
Moran
,
Emily V.
,
Motta
,
Renzo
,
Myers
,
Jonathan A.
,
Nagel
,
Thomas A.
,
Naoe
,
Shoji
,
Noguchi
,
Mahoko
,
Oguro
,
Michio
,
Parmenter
,
Robert R.
,
Pearse
,
Ian S.
,
Pérez-Ramos
,
Ignacio M.
,
Piechnik
,
Łukasz
,
Podgórski
,
Tomasz
,
Poulsen
,
John R.
,
Redmond
,
Miranda D.
,
Reid
,
Chantal D.
,
Rodman
,
Kyle C.
,
Rodríguez-Sánchez
,
Francisco
,
Šamonil
,
Pavel
,
Sanguinetti
,
Javier D.
,
Scher
,
C. Lane
,
Seget
,
Barbara
,
Sharma
,
Shubhi
,
Shibata
,
Mitsue
,
Silman
,
Miles R.
,
Steele
,
Michael A.
,
Stephenson
,
Nathan L.
,
Straub
,
Jacob N.
,
Sutton
,
Samantha
,
Swenson
,
Jennifer J.
,
Swift
,
Margaret
,
Thomas
,
Peter A.
,
Uríarte
,
María
,
Vacchiano
,
Giorgio
,
Whipple
,
Amy Vaughn
,
Whitham
,
Thomas G.
,
Wion
,
Andreas P.
,
Wright
,
Stuart Joseph
,
Zhu
,
Kai
,
Zimmerman
,
Jess K.
,
Żywiec
,
Magdalena
,
Clark
,
James S.
Mostra abstract
The benefits of masting (volatile, quasi-synchronous seed production at lagged intervals) include satiation of seed predators, but these benefits come with a cost to mutualist pollen and seed dispersers. If the evolution of masting represents a balance between these benefits and costs, we expect mast avoidance in species that are heavily reliant on mutualist dispersers. These effects play out in the context of variable climate and site fertility among species that vary widely in nutrient demand. Meta-analyses of published data have focused on variation at the population scale, thus omitting periodicity within trees and synchronicity between trees. From raw data on 12 million tree-years worldwide, we quantified three components of masting that have not previously been analysed together: (i) volatility, defined as the frequency-weighted year-to-year variation; (ii) periodicity, representing the lag between high-seed years; and (iii) synchronicity, indicating the tree-to-tree correlation. Results show that mast avoidance (low volatility and low synchronicity) by species dependent on mutualist dispersers explains more variation than any other effect. Nutrient-demanding species have low volatility, and species that are most common on nutrient-rich and warm/wet sites exhibit short periods. The prevalence of masting in cold/dry sites coincides with climatic conditions where dependence on vertebrate dispersers is less common than in the wet tropics. Mutualist dispersers neutralize the benefits of masting for predator satiation, further balancing the effects of climate, site fertility and nutrient demands. © 2023, The Author(s), under exclusive licence to Springer Nature Limited.
Linking seed size and number to trait syndromes in trees
Bogdziewicz
,
Michał
,
Aravena Acuña
,
Marie Claire
,
Andrus
,
Robert A.
,
Ascoli
,
Davide
,
Bergeron
,
Yves
,
Brveiller
,
Daniel
,
Boivin
,
Thomas
,
Bonal
,
Raúl
,
Caignard
,
Thomas
,
Cailleret
,
Maxime
,
Calama
,
Rafael A.
,
Calderon
,
Sergio Donoso
,
Camarero
,
Jesús Julio
,
Chang-Yang
,
Chia Hao
,
Chave
,
Jérôme
,
Chianucci
,
Francesco
,
Cleavitt
,
Natalie L.
,
Courbaud
,
Benoít
,
Cutini
,
Andrea
,
Curt
,
Thomas
,
Das
,
Adrian J.
,
Davi
,
Hendrik
,
Delpierre
,
Nicolas
,
Delzon
,
Sylvain
,
Dietze
,
Michael C.
,
Dormont
,
Laurent
,
Farfan-Rios
,
William R.
,
Gehring
,
Catherine A.
,
Gilbert
,
Gregory S.
,
Gratzer
,
Georg
,
Greenberg
,
Cathryn H.
,
Guignabert
,
Arthur
,
Guo
,
Qinfeng
,
Hacket-Pain
,
Andrew J.
,
Hampe
,
Arndt
,
Han
,
Qingmin
,
Hoshizaki
,
K.
,
Ibáñez
,
Inés
,
Johnstone
,
Jill F.
,
Journé
,
Valentin
,
Kitzberger
,
Thomas A.
,
Knops
,
Johannes Michael Hubertus
,
Kunstler
,
Georges
,
Kobe
,
Richard K.
,
Lageard
,
Jonathan G.A.
,
LaMontagne
,
Jalene M.
,
Ledwoń
,
Mateusz
,
Leininger
,
Theodor D.
,
Limousin
,
Jean Marc
,
Lutz
,
James A.
,
Macias
,
Diana S.
,
Mårell
,
Anders
,
McIntire
,
Eliot J.B.
,
Moran
,
Emily V.
,
Motta
,
Renzo
,
Myers
,
Jonathan A.
,
Nagel
,
Thomas A.
,
Naoe
,
Shoji
,
Noguchi
,
Mahoko
,
Oguro
,
Michio
,
Kurokawa
,
Hiroko
,
Ourcival
,
Jean Marc
,
Parmenter
,
Robert R.
,
Pérez-Ramos
,
Ignacio M.
,
Piechnik
,
Łukasz
,
Podgórski
,
Tomasz
,
Poulsen
,
John R.
,
Qiu
,
Tong
,
Redmond
,
Miranda D.
,
Reid
,
Chantal D.
,
Rodman
,
Kyle C.
,
Šamonil
,
Pavel
,
Holik
,
Jan
,
Scher
,
C. Lane
,
van Marle
,
Harald Schmidt
,
Seget
,
Barbara
,
Shibata
,
Mitsue
,
Sharma
,
Shubhi
,
Silman
,
Miles R.
,
Steele
,
Michael A.
,
Straub
,
Jacob N.
,
Sun
,
I. Fang
,
Sutton
,
Samantha
,
Swenson
,
Jennifer J.
,
Thomas
,
Peter A.
,
Uríarte
,
María
,
Vacchiano
,
Giorgio
,
Veblen
,
Thomas Thorstein
,
Wright
,
Boyd R.
,
Wright
,
Stuart Joseph
,
Whitham
,
Thomas G.
,
Zhu
,
Kai
,
Zimmerman
,
Jess K.
,
Żywiec
,
Magdalena
,
Clark
,
James S.
Mostra abstract
Aim: Our understanding of the mechanisms that maintain forest diversity under changing climate can benefit from knowledge about traits that are closely linked to fitness. We tested whether the link between traits and seed number and seed size is consistent with two hypotheses, termed the leaf economics spectrum and the plant size syndrome, or whether reproduction represents an independent dimension related to a seed size–seed number trade-off. Location: Most of the data come from Europe, North and Central America and East Asia. A minority of the data come from South America, Africa and Australia. Time period: 1960–2022. Major taxa studied: Trees. Methods: We gathered 12 million observations of the number of seeds produced in 784 tree species. We estimated the number of seeds produced by individual trees and scaled it up to the species level. Next, we used principal components analysis and generalized joint attribute modelling (GJAM) to map seed number and size on the tree traits spectrum. Results: Incorporating seed size and number into trait analysis while controlling for environment and phylogeny with GJAM exposes relationships in trees that might otherwise remain hidden. Production of the large total biomass of seeds [product of seed number and seed size; hereafter, species seed productivity (SSP)] is associated with high leaf area, low foliar nitrogen, low specific leaf area (SLA) and dense wood. Production of high seed numbers is associated with small seeds produced by nutrient-demanding species with softwood, small leaves and high SLA. Trait covariation is consistent with opposing strategies: one fast-growing, early successional, with high dispersal, and the other slow-growing, stress-tolerant, that recruit in shaded conditions. Main conclusions: Earth system models currently assume that reproductive allocation is indifferent among plant functional types. Easily measurable seed size is a strong predictor of the seed number and species seed productivity. The connection of SSP with the functional traits can form the first basis of improved fecundity prediction across global forests. © 2023 John Wiley & Sons Ltd.
A new method to estimate clumping index integrating gap fraction averaging with the analysis of gap size distribution
leaf area index
hemispherical photography
canopy nonrandomness
ordered weighted averaging (owa) operator
orness
Mostra abstract
Estimates of clumping index (Ω) are required to improve the indirect estimation of leaf area index (L) from optical field-based instruments such as digital hemispherical photography (DHP). A widely used method allows estimation of Ω from DHP using simple gap fraction averaging formulas (LX). This method is simple and effective but has the disadvantage of being sensitive to the spatial scale (i.e., the azimuth segment size in DHP) used for averaging and canopy density. In this study, we propose a new method to estimate Ω (LXG) based on ordered weighted gap fraction averaging (OWA) formulas, which addresses the disadvantages of LX and also accounts for gap size distribution. The new method was tested in 11 broadleaved forest stands in Italy; Ω estimated from LXG was compared with other commonly used clumping correction methods (LX, CC, and CLX). Results showed that LXG yielded more accurate Ω estimates, which were also more correlated with the values obtained from the gap size distribution methods (CC and CLX) than Ω obtained from LX. Leaf area index estimates, adjusted by LXG, are only 5%–6% lower than direct measurements obtained from litter traps, while other commonly used clumping correction methods yielded more underestimation. © 2019, Canadian Science Publishing. All rights reserved.
Comparison of seven inversion models for estimating plant andwoody area indices of leaf-on and leaf-off forest canopy using explicit 3D forest scenes
Zou
,
Jie
,
Zhuang
,
Yinguo
,
Chianucci
,
Francesco
,
Mai
,
Chunna
,
Lin
,
Weimu
,
Leng
,
Peng
,
Luo
,
Shezhou
,
Yan
,
Bojie
forest canopy
canopy element and woody component projection functions
clumping effect
digital hemispherical photography
forest scenes
inversion model
leaf area index (lai)
plant area index (pai)
woody area index (wai)
Mostra abstract
Optical methods require model inversion to infer plant area index (PAI) and woody area index (WAI) of leaf-on and leaf-off forest canopy from gap fraction or radiation attenuation measurements. Several inversion models have been developed previously, however, a thorough comparison of those inversion models in obtaining the PAI and WAI of leaf-on and leaf-off forest canopy has not been conducted so far. In the present study, an explicit 3D forest scene series with different PAI,WAI, phenological periods, stand density, tree species composition, plant functional types, canopy element clumping index, and woody component clumping index was generated using 50 detailed 3D tree models. The explicit 3D forest scene series was then used to assess the performance of seven commonly used inversion models to estimate the PAI andWAI of the leaf-on and leaf-off forest canopy. The PAI andWAI estimated from the seven inversion models and simulated digital hemispherical photography images were compared with the true PAI and WAI of leaf-on and leaf-off forest scenes. Factors that contributed to the differences between the estimates of the seven inversion models were analyzed. Results show that both the factors of inversion model, canopy element and woody component projection functions, canopy element and woody component estimation algorithms, and segment size are contributed to the differences between the PAI and WAI estimated from the seven inversion models. There is no universally valid combination of inversion model, needle-to-shoot area ratio, canopy element and woody component clumping index estimation algorithm, and segment size that can accurately measure the PAI and WAI of all leaf-on and leaf-off forest canopies. The performance of the combinations of inversion model, needle-to-shoot area ratio, canopy element and woody component clumping index estimation algorithm, and segment size to estimate the PAI and WAI of leaf-on and leaf-off forest canopies is the function of the inversion model as well as the canopy element and woody component clumping index estimation algorithm, segment size, PAI,WAI, tree species composition, and plant functional types. The impact of canopy element and woody component projection function measurements on the PAI and WAI estimation of the leaf-on and leaf-off forest canopy can be reduced to a low level ( < 4%) by adopting appropriate inversion models. © 2018 by the authors.