© 1996 Heron Publishing—Victoria, Canada
Carbon balance of the aerial parts of a young hinoki cypress (Chamaecyparis obtusa) stand
Stephen Adu-Bredu, Taketo Yokota and Akio Hagihara
Forest Ecophysiology Laboratory, Forest Sciences Division, School of Agricultural Sciences, Nagoya University, Nagoya 464-01,
Japan / Received March 2, 1995
Summary
The aerial carbon balance of a 9-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.) stand with an aerial biomass of 24.6 MgDW ha–1 was studied over a 1-year period. Various components that constitute gross production were measured on the basis of the summation
method. Respiration of the aerial parts of six sample trees was measured at monthly intervals by an enclosed standing-tree
method. The aerial respiration of sample trees was partitioned into growth and maintenance respiration by a two-component
model. The growth coefficient varied between 1.2791 and 1.7957 g CO2 gDW–1 giving a mean value of 1.5223 ± 0.0729 (SE) g CO2 gDW–1, whereas the maintenance coefficient ranged between 0.0200 and 0.0373 g CO2 gDW–1 month–1 with a mean value of 0.0299 ± 0.0031 (SE) g CO2 gDW–1 month–1. Growth and maintenance respiration of the stand were estimated to be 8.62 and 10.52 Mg CO2 ha–1 year–1, respectively. An open-top cloth trap method was employed to measure the death of the parts of five sample trees. The death
of leaves and total organs in the stand were assessed to be 6.26 and 7.60 MgDW ha–1 year–1, respectively. Tree mortality and biomass increment were 1.47 and 4.64 MgDW ha–1 year–1, respectively. In terms of carbon, respiration, death, grazing and biomass increment were equivalent to 5.22, 4.53, 0.04
and 2.32 Mg C ha–1 year–1, respectively. Net production and gross production were estimated to be 6.89 and 12.11 Mg C ha–1 year–1, respectively. Biomass accumulation ratio (biomass/net production) and overall efficiency (net production/gross production)
were 1.8 and 0.57, respectively.
Keywords:
biomass increment, grazing, gross production, growth respiration, maintenance respiration, net production.
