Diameter Growth, Biological Rotation Age and Biomass of Chinese Fir in Burning and Clearing Site Preparations in Subtropical China

Abstract

Sustained forest management of Cunninghamia lanceolata (Chinese fir) plantations in subtropical China is restricted by the limited availability of quantitative data. This study combines inventory data and tree-ring analysis of Chinese fir from natural and plantation forests that were subjected to controlled burning or brush clearing site preparations. Inter-annual variation of Chinese fir tree-ring widths were measured for the controlled burning, brush clearing and natural forest sites. The mean annual diametric growth of Chinese fir was 0.56 cm·year −1 for the natural forest, 0.80 cm·year −1 for the brush clearing site and 1.10 cm·year −1 for the controlled burning site. The time needed to reach the minimum cutting/logging diameter of 15 cm was 14 years in the controlled burning site, 19 years in the brush clearing site and >40 years in the natural forest. The biological rotation ages for the burning, cutting and natural forest sites were 15, 26 and >100 years, respectively. The total aboveground biomasses for the burning and clearing sites were 269.8 t·ha −1 and 252 t·ha −1 , respectively. These results suggest that the current 25-year cutting cycle greatly underestimates the growth rate of Chinese fir plantations.

Effects of prescribed burning on carbon accumulation in two paired vegetation sites in subtropical China

“…The biomass of fast-growing Eucalyptus increased fast as the nutrients were relatively abundant at the early stage. That prescribed burning increased tree biomass C storage to some extent in Eucalyptus plantations in the present study was consistent with that observed in Chinese fir plantations by Zhou et al (2016).…”

Long-Term Thinning Does not Significantly Affect Soil Water-Stable Aggregates and Diversity of Bacteria and Fungi in Chinese Fir (Cunninghamia lanceolata) Plantations in Eastern China

“…Aboveground vegetation is one of the primary sources of the soil nitrogen pool, and plant species affect nitrogen mineralization rates [64]. Some studies have shown that thinning increased the composition and biomass of the understory [47,65], which subsequently altered litter decomposition and nutrient status, and enhanced nitrogen input into soil [66]. Similarly, in the present study, we found that understory vegetation biomass, forest floor biomass, and nitrogen concentration associated with the thinning intensity had a positive correlation with soil nitrogen concentration (Table A1).…”

“…Chinese fir is native to China, Northern Vietnam, and Laos, and is one of the most important timber species in Southern China [46]. Chinese fir is a fast-growing tree species that accounts for 16% of all plantations in China, covering approximately 12 million ha [47]. A number of studies have mainly focused on Chinese fir growth and timber production [46,48,49].…”

Exploring the Sensitivity of Subtropical Stand Aboveground Productivity to Local and Regional Climate Signals in South China

“…It has been developed into a representative conifer and broadleaf mixed forest because a few natural broadleaf tree species (mentioned above) were reserved (ca. 10% of the initial aboveground biomass [48]) after cutting. The single-species forest (Sin) was completely cleared before 1988 and planted with Chinese fir in the late 1980s.…”

“…After the initial planting, a forest tending approach was implemented for 1 and 5 years. More supporting information on tree species composition, stand structure, hydrological characteristics, and soil parameters can be found in previous publications conducted at the same research site [37,48,49]. Meteorological data (air temperature, maximum air temperature, minimum air temperature, and precipitation) measured by a ground meteorological station ( Figure 1) were available to inform the calculation of the correlation with stand aboveground productivities.…”