Biomass, and carbon and nitrogen pools in a subtropical evergreen broad-leaved forest in eastern China

Abstract

Subtropical evergreen broad-leaved forest is the most widely distributed land-cover type in eastern China. As the rate of land-use change accelerates worldwide, it is becoming increasingly important to quantify ecosystem biomass and carbon (C) and nitrogen (N) pools. Above and below-ground biomass and ecosystem pools of N and C in a subtropical secondary forest were investigated at Laoshan Mountain Natural Reserve, eastern China. Total biomass was 142.9 Mg ha -1 for a young stand (18 years) and 421.9 Mg ha -1 for a premature stand (ca. 60 years); of this, root biomass was from 26.9 (18.8% of the total) to 100.3 Mg ha -1 (23.8%). Total biomass C and N pools were, respectively, 71.4 Mg ha -1 and 641.6 kg ha -1 in the young stand, and 217.0 Mg ha -1 and 1387.4 kg ha -1 in the premature stand. The tree layer comprised 91.8 and 89.4% of the total biomass C and N pools in the young stand, and 98.0 and 95.6% in the premature stand. Total ecosystem C and N pools were, respectively, 101.4 and 4.6 Mg ha -1 for the young stand, and 260.2 and 6.6 Mg ha -1 for the premature stand. Soil C comprised 23.8-29.6% of total ecosystem C whereas soil N comprised 76.9-84.4% of the total. Our results suggest that a very high percentage of N in this subtropical forest ecosystem is stored in the mineral soil, whereas the proportion of organic C in the soil pool is more variable. The subtropical forest in eastern China seems to rapidly accumulate biomass during secondary succession, which makes it a potentially rapid accumulator of, and large sink for, atmospheric C.

Sensitivity of subtropical forest and savanna productivity to climate variability in South America, Uruguay

“…This link between productivity and climate in subtropical South America implies that with increasing rainfall, the potential for carbon sequestration by native forests increases (Zhang et al. ). While native woodland cover is limited relative to the vast grasslands and agriculture that characterize the Rio de la Plata Basin (Eva et al.…”

“…While increasing annual rainfall and declining drought risk in southeastern South America is assumed to provide favourable climate conditions for forest growth, we provide some of the first evidence to show how different native woodland ecosystems in Uruguay respond to climate variability in terms of leaf phenology and productivity. This link between productivity and climate in subtropical South America implies that with increasing rainfall, the potential for carbon sequestration by native forests increases (Zhang et al 2010). While native woodland cover is limited relative to the vast grasslands and agriculture that characterize the Rio de la Plata Basin (Eva et al 2013), forests along riparian corridors are a critical buffer between a terrestrial landscape undergoing rapid agricultural intensification (Achkar et al 2011;Vassallo et al 2013) and a hydrological network that serves as the country's principal source of drinking water and energy (Conde & Sommruga 1999).…”

Carbon distribution and its correlation with floristic diversity in subtropical broad-leaved forests during natural succession

“…C storage in each soil layer was higher than young stands of subtropical, evergreen broadleaved forests in eastern China (12.70, 9.53 and 3.70 Mg C ha -1 in 0-10, 10-30 and 30-50 cm depth respectively) (Zhang et al 2010). Approximately 30% of soil C in the top 100 cm was stored in the 0-20 cm soil layer, which was lower than in a broad-leaved forest (40.9%) (Zhong & Zhao 2001).…”

“…Many ecological studies have reported community structure, composition, biodiversity and C storage assessment of subtropical broadleaved forests (Legendre et al 2009, Zhang et al 2010, Feng et al 2014. There are also studies focused on the relationship between C stocks and biodiversity for temperate (Hatanaka et al 2011) and tropical forests (Williams et al 2008, Cavanaugh et al 2014, Magnago et al 2015.…”

Nitrogen deposition and soil nitrogen dynamics in subtropical evergreen broad-leaved stands along an age-sequence

“…Permanent plots (30 m × 20 m) were set up in each stands, which were located at the centre to eliminate edge effects. The chronosequence was based on tree-ring counts for at least 15 canopy trees per stand (Zhang et al, 2010a). The general characteristics of the sampling stands are given in Table 1.…”