title: Stable carbon isotope labeling reveals different carry-over effects between functional types of tropical trees in an Ethiopian mountain forest.
abstract: We present an intra-annual stable carbon isotope (δ(13)C) study based on a labeling experiment to illustrate differences in temporal patterns of recent carbon allocation to wood structures of two functional types of trees, Podocarpus falcatus (a late-successional evergreen conifer) and Croton macrostachyus (a deciduous broadleaved pioneer tree), in a tropical mountain forest in Ethiopia. Dendrometer data, wood anatomical thin sections, and intra-annual δ(13)C analyses were applied. Isotope data revealed a clear annual growth pattern in both studied species. For P. falcatus, it was possible to synchronize annual δ(13) C peaks, wood anatomical structures and monthly precipitation patterns. The labeling signature was evident for three consecutive years. For C. macrostachyus, isotope data illustrate a rapid decline of the labeling signal within half a year. Our δ(13)C labeling study indicates a distinct difference in carryover effects between trees of different functional types. A proportion of the labeled δ(13)C is stored in reserves of wood parenchyma for up to 3 yr in P. falcatus. By contrast, C. macrostachyus shows a high turnover of assimilates and a carbon carryover effect is only detectable in the subsequent year.
authors.affiliation: Institute of Geography, University of Erlangen-Nuremberg, Kochstr 4/4, 91054, Erlangen, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Krepkowski
authors.affiliation: World Agroforestry Centre, PO Box 30677, Nairobi, Kenya.
authors.forename: Aster
authors.initials: A
authors.lastname: Gebrekirstos
authors.affiliation: Institute of Soil Science, Leibniz University Hannover, Herrenhäuser Str 2, 30419, Hannover, Germany.|V.N.Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, 660036, Krasnoyarsk, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Shibistova
authors.affiliation: Institute of Geography, University of Erlangen-Nuremberg, Kochstr 4/4, 91054, Erlangen, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Bräuning
mesh_terms: D002247:Carbon Isotopes; D017753:Ecosystem; D005002:Ethiopia; D007553:Isotope Labeling / Q000379:methods*; D014197:Trees / Q000378:metabolism*; D014329:Tropical Climate
chemical_list: D002247:Carbon Isotopes