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Cao J.,Beijing Forestry University | Cao J.,Chinese Academy of Forestry | Wang X.,Beijing Forestry Carbon Administration | Wang X.,Chinese Institute of Green Carbon | And 4 more authors.
Ecological Research | Year: 2012

The pattern of carbon (C) allocation across different stages of stand development of Chinese pine (Pinus tabulaeformis) forests is poorly documented. In order to understand the effects of stand age on the C pool of the Chinese pine forest ecosystem, we have examined the above- and belowground C pools in three differently aged stands of Chinese pine in the northern mountains of Beijing, China, by plot-level inventories and destructive sampling. Our results suggest that tree branch and foliage biomass should be estimated by age-specific equations. Reasonably accurate estimates of tree stem, tree root, aboveground, and total tree biomass in a Chinese pine forest at different development stages were obtained using age-independent allometric equations from tree diameter only. The ratio of belowground to aboveground tree biomass was relatively constant with stand aging, remaining around 21 %. The contribution of aboveground tree biomass C increased from 21 % of the total ecosystem C in a 25-year-old stand to 44 % in a 65-year-old stand, subsequently falling to 41 % in a 105-year-old stand, while the contribution of mineral soil C decreased from 64 % of the total ecosystem C in 25-year-old stand to 38 % in a 65-year-old stand, subsequently increasing to 41 % in a 105-year-old stand. The C stock of the total ecosystem and its aboveground tree, tree root, forest floor, and mineral soil components continuously increased with stand ageing, whereas the C stock of the understory showed a declining trend and contributed little to the total site C pool. © 2012 The Ecological Society of Japan.

Li H.,Beijing Forestry University | Li C.,Chinese Academy of Forestry | Zha T.,Beijing Forestry University | Liu J.,Beijing Forestry University | And 4 more authors.
Forestry Chronicle | Year: 2014

Tree biomass was investigated in an age-sequence of secondary lacebark pine (Pinus bungeana) forests to understand biomass partitioning patterns during stand development. Mean biomass of each tree component increased steadily as stands aged. Average growth rates and ratios of tree biomass to stand age increased with age. The ratio of below- to above-ground biomass remained relatively constant independent of stand age. Compared to DBH-H allometric equations, the DBH-only equations performed slightly better and are more efficient to apply. These new equations for lacebark pine are an important supplement to China's national tree biomass equations. These equations and the findings on biomass partitioning patterns during stand development are applicable for the accurate estimation of ecosystem carbon accounting and will contribute to the sustainable management of lacebark pine forests. © 2014 - Canadian Institute of Forestry.

Wang J.,Beijing Forestry University | Yu H.,Beijing Forestry Carbon Administration | Li G.,Beijing Forestry University | Zhang F.,Beijing Forestry Carbon Administration
Silva Fennica | Year: 2016

Stored nutrient reserves are closely correlated with survival and growth of transplanted seedlings. Previous studies have proven that combining pre-hardening fertilization (PF) with fall fertilization (FF) built seedling nutrient reserves more effectively; however, their effect on transplanting performance is poorly documented. We investigated the independent and interacting effects of 2 levels of PF and 4 levels of FF on seedling growth, nutrient acquisition and accumulation during different growth phases 1 year after transplanting of Quercus variabilis Blume in a nursery. High PF benefited nutrient reserves and subsequent transplanted seedling growth and tissue nutrient storage at the end of the rapid growth and hardening phases. Fall fertilization with 36 mg N increased stem dry mass and tissue nutrient content at the end of the hardening phase. At the conclusion of establishment, PF and FF showed a significant interaction for N and K uptake from soil. At the end of the rapid growth and hardening phases, high PF consistently increased nutrient uptake. Enhanced N and K uptake occurred following application of 36 mg N of FF at the end of the hardening phase. Distinct roles for PF and FF on 3 phases of transplanted seedlings demonstrated the necessity to evaluate fertilization in terms of nutrient reserves and subsequent transplanting performance in consecutive phases. Combining 100 mg N seedling–1 during pre-hardening with 36 mg N seedling–1 during fall yielded ideal transplanting performance for Quercus variabilis seedlings. © 2016, Finnish Society of Forest Science. All right reserved.

Chen B.,Beijing Forestry University | Wang X.,Beijing Forestry University | Chen J.,Beijing Forestry Carbon Administration | Zhu J.,Beijing Forestry Carbon Administration | Liu J.,Beijing Forestry University
Forestry Chronicle | Year: 2015

Tree planting has been proposed by Beijing's municipal government as a measure to alleviate airborne fine particulate matter (PM) in the city as trees have large surface areas to filter pollution out of the air. To maximize this eco-efficiency, a series of active measures have been taken by the city's forestry sector. These strategies are elaborated here to provide a valuable reference for other megacities facing similar challenges. © 2015 Published by NRC Research Press.

Chen W.,Beijing Forestry University | Jia X.,Beijing Forestry University | Zha T.,Beijing Forestry University | Zha T.,Chinese Institute of Green Carbon | And 8 more authors.
European Journal of Soil Biology | Year: 2013

We investigated how soil temperature (Ts) and water content (VWC) affect soil respiration (Rs) in a mixed urban forest. Continuous half-hourly measurements of soil surface efflux were made during the period March-December 2011 in a mixed forest in Beijing Olympic Forest Park, China. Daily mean Rs varied from 0.28 to 3.62 μmol CO2 m-2 s-1. Over this period of record, Rs increased exponentially with rising temperature; a Q10 model with 5-cm soil temperature as the independent variable explained 76% of the variation in half-hourly Rs. The temperature sensitivity of respiration (Q10) varied seasonally, being greater in fall than in spring, suggesting seasonal hysteresis in the Rs-Ts relationship. During the summer months (June-August 2011), when Ts was high and had relatively little day-to-day variation, Rs was hyperbolically related to VWC, increasing with increasing VWC up to a VWC threshold of 0.17 m3 m-3, but decreasing with increasing VWC above the threshold. A bivariate Q10-hyperbolical model, which incorporated both Ts and VWC effects, improved the performance of Rs simulation in summer, but not annually. These results indicated that Rs was dominantly controlled by soil temperature over the annual cycle. However, VWC served as the dominant control in summer. The annual total of Rs estimated from the Q10 model was 475 g C m-2. We recommend the use of the Q10 model for predicting annual soil respiration due to its good performance and physiological basis. © 2012 Elsevier Masson SAS.

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