This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/GCB.14906 This article is protected by copyright. All rights reserved DR. DANIELE CASTAGNERI (Orcid ID : 0000-0002-2092-7415) DR. MARCO CARRER (Orcid ID : 0000-0003-1581-6259) Article type : Primary Research Articles Wood anatomical traits in black spruce reveal latent water constraints on the boreal forest Running head: Latent water constraint on black spruce PAULINA F. PUCHI 1 , DANIELE CASTAGNERI 1,2* , SERGIO ROSSI 3,4 and MARCO CARRER 1 1 Universitá degli Studi di Padova, Dipartimento Territorio e Sistemi Agro-Forestali (TESAF), Via dell'Università 16, 35020 Legnaro (PD), Italy 2 Swiss Federal Research Institute (WSL), Zurcherstrasse 111, 8903 Birmensdorf (ZH), Switzerland 3 Université du Québec à Chicoutimi, Département des Sciences Fondamentales, 555 Boulevard de l'Université, G7H2B1 Chicoutimi (QC), Canada 4 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, China * Corresponding author ORCID ID: 0000-0002-2092-7415 e-mail: daniele.castagneri@unipd.it phone: +39 049 827 2725 Accepted Article