title: Woody biomass production lags stem-girth increase by over one month in coniferous forests.
abstract: Wood is the main terrestrial biotic reservoir for long-term carbon sequestration(1), and its formation in trees consumes around 15% of anthropogenic carbon dioxide emissions each year(2). However, the seasonal dynamics of woody biomass production cannot be quantified from eddy covariance or satellite observations. As such, our understanding of this key carbon cycle component, and its sensitivity to climate, remains limited. Here, we present high-resolution cellular based measurements of wood formation dynamics in three coniferous forest sites in northeastern France, performed over a period of 3 years. We show that stem woody biomass production lags behind stem-girth increase by over 1 month. We also analyse more general phenological observations of xylem tissue formation in Northern Hemisphere forests and find similar time lags in boreal, temperate, subalpine and Mediterranean forests. These time lags question the extension of the equivalence between stem size increase and woody biomass production to intra-annual time scales(3, 4, 5, 6). They also suggest that these two growth processes exhibit differential sensitivities to local environmental conditions. Indeed, in the well-watered French sites the seasonal dynamics of stem-girth increase matched the photoperiod cycle, whereas those of woody biomass production closely followed the seasonal course of temperature. We suggest that forecasted changes in the annual cycle of climatic factors(7) may shift the phase timing of stem size increase and woody biomass production in the future.
authors.affiliation: INRA, UMR 1092 LERFOB, Champenoux F-54280, France.|AgroParisTech, UMR 1092 LERFOB, Nancy F-54000, France.|Swiss Federal Research Institute WSL, Birmensdorf CH-8903, Switzerland.
authors.forename: Henri E
authors.initials: HE
authors.lastname: Cuny
authors.affiliation: INRA, UMR 1092 LERFOB, Champenoux F-54280, France.|AgroParisTech, UMR 1092 LERFOB, Nancy F-54000, France.
authors.forename: Cyrille B K
authors.initials: CB
authors.lastname: Rathgeber
authors.affiliation: Swiss Federal Research Institute WSL, Birmensdorf CH-8903, Switzerland.|Oeschger Centre for Climate Change Research, Bern CH-3012, Switzerland.
authors.forename: David
authors.initials: D
authors.lastname: Frank
authors.affiliation: Swiss Federal Research Institute WSL, Birmensdorf CH-8903, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Fonti
authors.affiliation: Natural Resources Institute Finland, PO Box 18, Vantaa 01301, Finland.
authors.forename: Harri
authors.initials: H
authors.lastname: Mäkinen
authors.affiliation: Slovenian Forestry Institute, Vecna pot 2, Ljubljana 1000, Slovenia.
authors.forename: Peter
authors.initials: P
authors.lastname: Prislan
authors.affiliation: Université du Québec à Chicoutimi, Chicoutimi, QC G7H 2B1, Canada.|Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Provincial Key Laboratory of Applied Botany South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Sergio
authors.initials: S
authors.lastname: Rossi
authors.affiliation: Department of Geography and Regional Planning, Environmental Science Institute (IUCA), University of Zaragoza, C/Pedro Cerbuna 12, Zaragoza 50009, Spain.
authors.forename: Edurne Martinez
authors.initials: EM
authors.lastname: Del Castillo
authors.affiliation: Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra 3000-456, Portugal.
authors.forename: Filipe
authors.initials: F
authors.lastname: Campelo
authors.affiliation: Faculty of Forestry and Wood Technology, Department of Wood Science, Mendel University in Brno, Zemědělská 3, Brno 613 00, Czech Republic.
authors.forename: Hanuš
authors.initials: H
authors.lastname: Vavrčík
authors.affiliation: Instituto Pirenaico de Ecología (IPE-CSIC), Avda. Montañana 1005, Zaragoza 50192, Spain.
authors.forename: Jesus Julio
authors.initials: JJ
authors.lastname: Camarero
authors.affiliation: V.N. Sukachev Institute of Forest, SB RAS, Krasnoyarsk 660036, Russia.|Siberian Federal University, 660041 Krasnoyarsk, Russia.
authors.forename: Marina V
authors.initials: MV
authors.lastname: Bryukhanova
authors.affiliation: Natural Resources Institute Finland, PO Box 18, Vantaa 01301, Finland.
authors.forename: Tuula
authors.initials: T
authors.lastname: Jyske
authors.affiliation: Slovenian Forestry Institute, Vecna pot 2, Ljubljana 1000, Slovenia.
authors.forename: Jožica
authors.initials: J
authors.lastname: Gričar
authors.affiliation: Faculty of Forestry and Wood Technology, Department of Wood Science, Mendel University in Brno, Zemědělská 3, Brno 613 00, Czech Republic.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Gryc
authors.affiliation: Department of Geography and Regional Planning, Environmental Science Institute (IUCA), University of Zaragoza, C/Pedro Cerbuna 12, Zaragoza 50009, Spain.
authors.forename: Martin
authors.initials: M
authors.lastname: De Luis
authors.affiliation: Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra 3000-456, Portugal.
authors.forename: Joana
authors.identifier: http://orcid.org/0000-0003-1021-4101
authors.initials: J
authors.lastname: Vieira
authors.affiliation: Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, Ljubljana 1000, Slovenia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Čufar
authors.affiliation: V.N. Sukachev Institute of Forest, SB RAS, Krasnoyarsk 660036, Russia.|Siberian Federal University, 660041 Krasnoyarsk, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kirdyanov
authors.affiliation: University of Innsbruck, Institute of Botany, Sternwartestrasse 15, Innsbruck 6020, Austria.
authors.forename: Walter
authors.initials: W
authors.lastname: Oberhuber
authors.affiliation: Faculty of Science, Charles University in Prague, Prague CZ-12843, Czech Republic.
authors.forename: Vaclav
authors.initials: V
authors.lastname: Treml
authors.affiliation: Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, Provincial Key Laboratory of Applied Botany South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Jian-Guo
authors.identifier: http://orcid.org/0000-0003-3830-0415
authors.initials: JG
authors.lastname: Huang
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes and Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Li
authors.affiliation: University of Innsbruck, Institute of Botany, Sternwartestrasse 15, Innsbruck 6020, Austria.
authors.forename: Irene
authors.initials: I
authors.lastname: Swidrak
authors.affiliation: Université du Québec à Chicoutimi, Chicoutimi, QC G7H 2B1, Canada.
authors.forename: Annie
authors.initials: A
authors.lastname: Deslauriers
authors.affiliation: Key Laboratory of Tibetan Environment Changes and Land Surface Processes and Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Eryuan
authors.initials: E
authors.lastname: Liang
authors.affiliation: Natural Resources Institute Finland, PO Box 18, Vantaa 01301, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Nöjd
authors.affiliation: University of Innsbruck, Institute of Botany, Sternwartestrasse 15, Innsbruck 6020, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Gruber
authors.affiliation: Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra 3000-456, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Nabais
authors.affiliation: Université du Québec à Chicoutimi, Chicoutimi, QC G7H 2B1, Canada.
authors.forename: Hubert
authors.initials: H
authors.lastname: Morin
authors.affiliation: Université du Québec à Chicoutimi, Chicoutimi, QC G7H 2B1, Canada.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Krause
authors.affiliation: Department of Geography, Queen's University, Kingston, Canada.
authors.forename: Gregory
authors.initials: G
authors.lastname: King
authors.affiliation: INRA, UMR 1092 LERFOB, Champenoux F-54280, France.|AgroParisTech, UMR 1092 LERFOB, Nancy F-54000, France.
authors.forename: Meriem
authors.initials: M
authors.lastname: Fournier