Long‐term carbon budget of the above‐ground parts of a young hinoki cypress (Chamaecyparis obtusa) stand

Abstract

The carbon budget of the above‐ground parts of a young hinoki (Chamaecyparis obtusa) stand was analyzed over a 4‐year period to evaluate trends in changes in carbon use efficiency and growth conversion (biosynthetic) efficiency with stand development. Litter production of the stand was estimated from the stem cross‐sectional area at the crown base. A biomass increment was estimated using the stem volume of individual trees in the stand, measured at monthly intervals. Net production, estimated from litter production and the biomass increment, was 7.40, 8.44, 8.45 and 8.29 Mg C ha−1 year−1 for Years I–IV, respectively. The respiration rate of the entire above‐ground parts of selected sample trees were measured at monthly intervals using the enclosed whole‐tree method. The Q10 value of respiration decreased with increasing air temperature. Respiration rate was partitioned into growth and maintenance components using a two‐component functional model. The maintenance respiration coefficient increased in the following order: winter, spring, autumn and summer. The maintenance respiration coefficient also decreased with either stand development or age for all seasons. The growth respiration coefficient, which did not vary with stand development, was 0.69 ± 0.08 (mean ± SE), 0.61 ± 0.03, 0.54 ± 0.03 and 0.67 ± 0.07 g C g−1 C for winter, spring, summer and autumn, respectively. The growth conversion efficiency of the stand was 0.76, 0.72, 0.72 and 0.75 for Years I–IV, respectively. Carbon use efficiency was estimated to be 0.58, 0.57, 0.54 and 0.53 for Years I–IV, respectively. The hypothesis that respiration reduces productivity in old stands could not be validated for this hinoki stand.

Litterfall and associated nutrient pools extend beyond the canopy of scattered eucalypt trees in temperate pastures

“…In evergreen forest systems (eucalypts and other species), it is typically reported that leaf litter represents >50%, and often >70%, of total annual litterfall (Lamb 1985;O'Connell 1988;Pook et al 1997;Sundarapandian and Swamy 1999;Adu-bredu and Hagihara 2003). In our study however, leaf litter contributed only 23-34% of the total amount of litter.…”

The partitioning of gross primary production for young Eucalyptus tereticornis trees under experimental warming and altered water availability

“…Given the evidence for thermal acclimation of tissue-specific respiration rates to experimental warming in this experiment (Aspinwall et al, 2016;Drake et al, 2016b), we investigated growth and maintenance respiration as drivers of R a (McCree, 1970;Tjoelker et al, 1999;Amthor, 2000;Adu-Bredu & Hagihara, 2003). Separating growth and maintenance components of R a is not possible in all C-cycle studies, but we were able to couple direct measures of tree growth with continuous measurements of integrated whole-tree aboveground respiration to enable quantification of growth and maintenance components.…”

Dendrometry and litterfall of neotropical pioneer and early secondary tree species

“…The significant correlation between stem diameter and annual litterfall among the different tree species suggests that such correlation could be true in interspecific comparisons, at least among pioneer and early secondary tree species, as the intraspecific correlation observed by Adu-Bredu & Hagihara (2003). On the other hand, crown width seems to be as good predictor of litter production as stem diameter, in these early stages of succession.…”