Spatial and temporal patterns in stand structure, biomass, growth, and mortality in a monospecific Nothofagus solandri var. cliffortioides (Hook. f.) Poole forest in New Zealand.
Measurements in 1970 on 250 permanent plots (20×20 m) in Nothofagus solandri [N. solanderi] var. cliffortioides in the Craigieburn Range, Canterbury, New Zealand, showed that stem density was 2191/ha, basal area was 52.4 m2/ha, and stem biomass was 178.1 t/ha. Net production of stemwood (1974-87) was 2.0 t/ha per year; annual mortality was 3.5 t/ha. By 1987, density had decreased by 30%, basal area by 12%, and stem biomass by 13%. Stands with many short trees of small mean diameter at breast height (dbh) were common at high altitude, whereas stands with fewer, taller trees with large mean dbh were common at low altitude. Stemwood production and mortality rate were higher in tall stands. Mortality was well distributed among plots, indicating small, frequent canopy openings; stand turnover calculations were 66 years (based on 2.2% annual biomass loss) to 83 years (based on 1.2% annual stemwood production). Larger canopy openings were also evident, but were more infrequent, so stand turnover times due to 'catastrophic' disturbances were in the range of 350-4000 years. Consequently, the small, high-frequency disturbances blurred effects of larger disturbances on stand structure and also constrained the fluctuation in forest biomass.