title: Structure and Function of Intra-Annual Density Fluctuations: Mind the Gaps.
abstract: Tree rings are natural archives of climate and environmental information with a yearly resolution. Indeed, wood anatomical, chemical, and other properties of tree rings are a synthesis of several intrinsic and external factors, and their interaction during tree growth. In particular, Intra-Annual Density Fluctuations (IADFs) can be considered as tree-ring anomalies that can be used to better understand tree growth and to reconstruct past climate conditions with intra-annual resolution. However, the ecophysiological processes behind IADF formation, as well as their functional impact, remain unclear. Are IADFs resulting from a prompt adjustment to fluctuations in environmental conditions to avoid stressful conditions and/or to take advantage from favorable conditions? In this paper we discuss: (1) the influence of climatic factors on the formation of IADFs; (2) the occurrence of IADFs in different species and environments; (3) the potential of new approaches to study IADFs and identify their triggering factors. Our final aim is to underscore the advantages offered by network analyses of data and the importance of high-resolution measurements to gain insight into IADFs formation processes and their relations with climatic conditions, including extreme weather events.
authors.affiliation: Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Second University of NaplesCaserta, Italy; Centre for Bio-Archaeology and Ecology, PALECO Ecole Pratique des Hautes Etudes, Institut des Sciences de l'Evolution, University of Montpellier 2Montpellier, France; Euro-Mediterranean Center on Climate ChangeLecce, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Battipaglia
authors.affiliation: Department of Life Sciences, Centre for Functional Ecology, University of Coimbra Coimbra, Portugal.
authors.forename: Filipe
authors.initials: F
authors.lastname: Campelo
authors.affiliation: Department of Life Sciences, Centre for Functional Ecology, University of Coimbra Coimbra, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Vieira
authors.affiliation: Institute of Wood Technology and Renewable Resources, University of Natural Resources and Life Sciences Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Grabner
authors.affiliation: Department of Agricultural Sciences, University of Naples Federico II Naples, Italy.
authors.forename: Veronica
authors.initials: V
authors.lastname: De Micco
authors.affiliation: Department of Life Sciences, Centre for Functional Ecology, University of Coimbra Coimbra, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Nabais
authors.affiliation: Swiss Federal Research Institute WSL Birmensdorf, Switzerland.
authors.forename: Paolo
authors.initials: P
authors.lastname: Cherubini
authors.affiliation: Department of Land, Environment, Agriculture and Forestry, University of Padua Padua, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Carrer
authors.affiliation: Department of Geography and Geosciences, Institute of Geography, Friedrich-Alexander-University Erlangen-Nuremberg Erlangen, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Bräuning
authors.affiliation: Department of Wood Science and Technology, Biotechnical Faculty, University of Ljubljana Ljubljana, Slovenia.
authors.forename: Katarina
authors.initials: K
authors.lastname: Čufar
authors.affiliation: Department Agricultural and Forestry, Università degli Studi della Tuscia Viterbo, Italy.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Di Filippo
authors.affiliation: Departamento de Botánica, Escuela Politécnica Superior, University of Santiago de Compostela Lugo, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: García-González
authors.affiliation: Faculty of Biology and Environment Protection, Nicolaus Copernicus University Toruñ, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Koprowski
authors.affiliation: Department of Silviculture and Genetics, Forest Research Institute in Poland Budynek, Poland.
authors.forename: Marcin
authors.initials: M
authors.lastname: Klisz
authors.affiliation: V.N. Sukachev Institure of Forest SB RASKrasnoyarsk, Russia; Department of Math Methods and IT, Siberian Federal UniversityKrasnoyarsk, Russia.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Kirdyanov
authors.affiliation: Department of Plant Pathology and Chemistry, University of Forestry Sofia, Bulgaria.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Zafirov
authors.affiliation: Department of Geography and Regional Planning-IUCA, University of Zaragoza Zaragoza, Spain.
authors.forename: Martin
authors.initials: M
authors.lastname: de Luis
keywords: IADF; network analysis; stable isotopes; tree-ring; wood anatomy; wood formation