title: Seasonal variations in the stable oxygen isotope ratio of wood cellulose reveal annual rings of trees in a Central Amazon terra firme forest.
abstract: In Amazonian non-flooded forests with a moderate dry season, many trees do not form anatomically definite annual rings. Alternative indicators of annual rings, such as the oxygen (δ(18)Owc) and carbon stable isotope ratios of wood cellulose (δ(13)Cwc), have been proposed; however, their applicability in Amazonian forests remains unclear. We examined seasonal variations in the δ(18)Owc and δ(13)Cwc of three common species (Eschweilera coriacea, Iryanthera coriacea, and Protium hebetatum) in Manaus, Brazil (Central Amazon). E. coriacea was also sampled in two other regions to determine the synchronicity of the isotopic signals among different regions. The annual cyclicity of δ(18)Owc variation was cross-checked by (14)C dating. The δ(18)Owc showed distinct seasonal variations that matched the amplitude observed in the δ(18)O of precipitation, whereas seasonal δ(13)Cwc variations were less distinct in most cases. The δ(18)Owc variation patterns were similar within and between some individual trees in Manaus. However, the δ(18)Owc patterns of E. coriacea differed by region. The ages of some samples estimated from the δ(18)Owc cycles were offset from the ages estimated by (14)C dating. In the case of E. coriacea, this phenomenon suggested that missing or wedging rings may occur frequently even in well-grown individuals. Successful cross-dating may be facilitated by establishing δ(18)Owc master chronologies at both seasonal and inter-annual scales for tree species with distinct annual rings in each region.
authors.affiliation: Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan. shinta.res@gmail.com.
authors.forename: Shinta
authors.initials: S
authors.lastname: Ohashi
authors.affiliation: National Institute for Amazon Research (INPA), 69060-000, Manaus, AM, Brazil.
authors.forename: Flávia M
authors.initials: FM
authors.lastname: Durgante
authors.affiliation: Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kagawa
authors.affiliation: Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kajimoto
authors.affiliation: University of California, Irvine, CA, 92697-3100, USA.|Max Planck Institute for Biogeochemistry, 07745, Jena, Thuringia, Germany.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Trumbore
authors.affiliation: University of California, Irvine, CA, 92697-3100, USA.
authors.forename: Xiaomei
authors.initials: X
authors.lastname: Xu
authors.affiliation: Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, 305-8687, Japan.|Japan International Forestry Promotion and Cooperation Center, Bunkyo, Tokyo, 112-0004, Japan.
authors.forename: Moriyoshi
authors.initials: M
authors.lastname: Ishizuka
authors.affiliation: National Institute for Amazon Research (INPA), 69060-000, Manaus, AM, Brazil.
authors.forename: Niro
authors.initials: N
authors.lastname: Higuchi
mesh_terms: D001938:Brazil; D002247:Carbon Isotopes / Q000032:analysis; D002482:Cellulose / Q000737:chemistry*; D065928:Forests; D010103:Oxygen Isotopes / Q000032:analysis*; D012621:Seasons; D014197:Trees / Q000737:chemistry* / Q000254:growth & development; D014934:Wood / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D010103:Oxygen Isotopes; D002482:Cellulose
keywords: Radiocarbon dating; Stable carbon isotope ratio; Tree-ring detection; Tropical moist forest; Wood anatomy