Biomass, Carbon and Nutrient Storage in a 30-Year-Old Chinese Cork Oak (Quercus Variabilis) Forest on the South Slope of the Qinling Mountains, China

Abstract

Chinese cork oak (Quercus variabilis) forests are protected on a large-scale under the Natural Forest Protection (NFP) program in China to improve the ecological environment. However, information about carbon (C) storage to increase C sequestration and sustainable management is lacking. Biomass, C, nitrogen (N) and phosphorus (P) storage of trees, shrubs, herb, litter and soil (0-100 cm) were determined from destructive tree sampling and plot level investigation in approximately 30-year old Chinese cork oak forests on the south slope of the Qinling Mountains. There was no significant difference in tree components' biomass estimation, with the exception of roots, among the available allometric equations developed from this study site and other previous study sites. Leaves had the highest C, N and P concentrations among tree components and stems were the major compartments for tree biomass, C, N and P storage. In contrast to finding no difference in N concentrations along the whole soil profile, higher C and P concentrations were observed in the upper 0-10 cm of soil than in the deeper soil layers. The ecosystem C, N, and P storage was 163.76, 18.54 and 2.50 t ha −1 , respectively. Soil (0-100 cm) contained the largest amount of C, N and P storage, accounting for 61.76%, 92.78% and 99.72% of the total ecosystem, followed by 36.14%, 6.03% and 0.23% for trees, and 2.10%, 1.19% and 0.03% for shrubs, herbs and litter, respectively. The equations accurately estimate ecosystem biomass, and the OPEN ACCESSForests 2015, 6 1240 knowledge of the distribution of C, N and P storage will contribute to increased C sequestration and sustainable management of Chinese cork oak forests under the NFP program.

C:N:P Stoichiometry and Carbon Storage in a Naturally-Regenerated Secondary Quercus variabilis Forest Age Sequence in the Qinling Mountains, China

“…Biomass of all age classes in this study were all larger than that of natural Quercus wutaishanica forest (young and middle-aged stands 76.02 Mg·ha −1 , near-mature stands 79.35 Mg·ha −1 , mature stands 96.71 Mg·ha −1 ) in Ziwuling of Loess Plateau [43]. Consistent with previous studies, the biomass of stems accounted for the largest proportion, roots secondly, leaves the least in tree tissues of all age classes [25,42]. The biomass of understory vegetation was 1.99-5.66 Mg·ha −1 in different age classes, and the biomass of understory vegetation and litter accounted for small proportion of the stand biomass (young stands 11.47%, middle-aged stands 5.77%, near-mature stands 6.57%, mature stands 8.06%), which was also consistent with previous studies [25].…”

“…Consistent with previous studies, the biomass of stems accounted for the largest proportion, roots secondly, leaves the least in tree tissues of all age classes [25,42]. The biomass of understory vegetation was 1.99-5.66 Mg·ha −1 in different age classes, and the biomass of understory vegetation and litter accounted for small proportion of the stand biomass (young stands 11.47%, middle-aged stands 5.77%, near-mature stands 6.57%, mature stands 8.06%), which was also consistent with previous studies [25]. This may be associated with forest management, canopy structure, and soil conditions, which affect the growth of understory vegetation by light, nutrition and hydrothermal conditions [26].…”

“…The biomass of tree components, including leaves, branches, stems, barks and roots, were generally estimated using different allometric regression models based on DBH or DBH-H [26]. The allometric regression models used in this study were developed in the Shangluo county area in Qinling Mountain area in early August 2013, and the detailed operation process was recorded by Cao Y and Chen YM [25]. The allometric regression models are shown in Table 1.…”

“…Under the Natural Forest Protection (NFP) program in China, their potential carbon sequestration will be greatly improved. A growing number of studies have addressed C storage and sequestration in key national ecological restoration programs in China [25], such as Three-North Shelterbelt Forest program, the Sloping Land Conversion program, Beijing-Tianjin Sandstorm Source Control program, Changjiang (Yangtze) River Basin Forest Protection program. However, there is still a lack of focus on the NFP program and the biomass and C storage of Quercus variabilis natural secondary forests in the Qinling Mountain area, which is crucial for prediction of the responses of regional and global carbon balance to future climate change.…”

Variations and determinants of carbon content in plants: a global synthesis

“…However, an increasing number of studies have indicated that C content varied significantly among plant organs (Alriksson and Eriksson, 1998;Bert and Danjon, 2006;Yao et al, 2015), life forms (Tolunay, 2009;Fang et al, 2010;Cao and Chen, 2015), biomes (He et al, 2006;Martin and Thomas, 2011;Martin et al, 2015), and even across individuals (Elias and Potvin, 2003;Uri et al, 2012;Martin et al, 2013). Using the default value of 50 % as biomass C con-version factor which ignores the variation of C content may lead to biases (Zhang et al, 2009;Martin and Thomas, 2011;Rodrigues et al, 2015).…”