Stable carbon isotope labeling reveals different carry‐over effects between functional types of tropical trees in an Ethiopian mountain forest

Abstract

SummaryWe present an intra-annual stable carbon isotope (d 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 d 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 d 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 d 13 C labeling study indicates a distinct difference in carryover effects between trees of different functional types. A proportion of the labeled d 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.

Wet season precipitation during the past century reconstructed from tree-rings of a tropical dry forest in Southern Ecuador

“…On the other hand, for the species C. scabrida, C. trichistandra, C. loxensis, C. mollis, I. calodendrum, T. chrysantha, T. valverdae and Viguiera sp., it was not feasible to develop chronologies, although their growth behavior is probably also influenced by climatic factors. More detailed wood and tree physiological anatomical studies are necessary to identify their growth rates and their rings borders, as intra-annual stable isotope analysis (Anchukaitis et al, 2008;Evans and Schrag, 2004;Krepkowski et al, 2013). So far, annual rings of these species have only been reported for T. chrysantha (Volland-Voigt et al, 2011).…”

Age-Effect on Intra-Annual δ13C-Variability within Scots Pine Tree-Rings from Central Siberia

“…Recent observations with intra-annual resolution are providing a more detailed picture of tree-ring structural-functional relationships due to environmental changes or extreme events [18][19][20][21]. Moreover, there are indications that younger trees better capture the environmental signal than older trees, and thus, allow us to better distill information on short-term environmental control.…”

Nonstructural Carbon in Woody Plants

“…Trees utilize recent NSC (current and previous year) for reproductive masting-years of large, synchronized seed production among conspecific individuals-regardless of the interval between mast years (52). New roots, leaf buds, and flowers grow from stored NSC up to two years old (52,139), and stored NSC up to three or four years old has been incorporated into tree ring cellulose growth (54,65). NSC used for root (14,22,51) and stem (12,87) respiration can be several years old.…”