Changes in carbon stocks of <i>Fagus</i> forest ecosystems along an altitudinal gradient on Mt. Fanjingshan in Southwest China

2018 ◽  
Author(s):  
Qiong Cai ◽  
Chengjun Ji ◽  
Xuli Zhou ◽  
Wenjing Fang ◽  
Tianli Zheng ◽  
...  

Abstract. There are four components of carbon (C) pools in a natural forest ecosystem: vegetation, soil, litter and woody debris. Quantifying these C pools and their contributions to forest ecosystems is important in understanding C cycling in forests. Here, we investigated these four C pools in nine beech (Fagus L., Fagaceae) forests along an altitudinal gradient in southwest China. We found that the C pools of beech forest ecosystems ranged from 190.7 to 503.9 Mg C ha−1, mainly attributed to vegetation C (accounting for 33.7–73.9 %) and soil C (accounting for 24.6–65.4 %). No more than 4 % of ecosystem C pools were stored in woody debris (0.25–3.4 %) and litter (0.2–0.7 %). Ecosystem C storage increased significantly with altitude, where the vegetation and woody debris C pools increased concomitantly with increasing altitude, while those of litter and soil exhibited no significant variations. The forest stand age was found to be a key driver of such altitudinal patterns, especially for vegetation C storage. The present study provides reliable data for understanding the structure and function of Chinese beech forests, and emphasizes the importance of considering the influence of stand age on C accumulation.

2019 ◽  
Vol 13 (2) ◽  
pp. 139-149
Author(s):  
Qiong Cai ◽  
Chengjun Ji ◽  
Xuli Zhou ◽  
Helge Bruelheide ◽  
Wenjing Fang ◽  
...  

Abstract Aims There are different components of carbon (C) pools in a natural forest ecosystem: biomass, soil, litter and woody debris. We asked how these pools changed with elevation in one of China’s ecologically important forest ecosystem, i.e. beech (Fagus L., Fagaceae) forests, and what were the underlying driving factors of such variation. Methods The four C pools in nine beech forests were investigated along an elevational gradient (1095–1930 m) on Mt. Fanjingshan in Guizhou Province, Southwest China. Variance partitioning was used to explore the relative effects of stand age, climate and other factors on C storage. In addition, we compared the four C pools to other beech forests in Guizhou Province and worldwide. Important Findings The total C pools of beech forest ecosystems ranged from 190.5 to 504.3 Mg C ha–1, mainly attributed to biomass C (accounting for 33.7–73.9%) and soil C (accounting for 23.9–65.5%). No more than 4% of ecosystem C pools were stored in woody debris (0.05–3.1%) and litter (0.2–0.7%). Ecosystem C storage increased significantly with elevation, where both the biomass and woody debris C pools increased with elevation, while those of litter and soil exhibited no such trend. For the Guizhou beech forests, climate and stand age were found to be key drivers of the elevational patterns of ecosystem and biomass C storage, while for beech forests globally, stand age was the most important predictor. Compared to beech forests worldwide, beech forests in Guizhou Province displayed a relatively higher biomass C accumulation rate, which may be explained by a much higher precipitation in this area. The present study provides basic data for understanding the C budgets of Chinese beech forests and their possible roles in regional C cycling and emphasizes the general importance of stand age and climate on C accumulation.


2016 ◽  
Vol 2 (4) ◽  
pp. 165-182 ◽  
Author(s):  
Chelsea L. Petrenko ◽  
Julia Bradley-Cook ◽  
Emily M. Lacroix ◽  
Andrew J. Friedland ◽  
Ross A. Virginia

Shrub species are expanding across the Arctic in response to climate change and biotic interactions. Changes in belowground carbon (C) and nitrogen (N) storage are of global importance because Arctic soils store approximately half of global soil C. We collected 10 (60 cm) soil cores each from graminoid- and shrub-dominated soils in western Greenland and determined soil texture, pH, C and N pools, and C:N ratios by depth for the mineral soil. To investigate the relative chemical stability of soil C between vegetation types, we employed a novel sequential extraction method for measuring organo-mineral C pools of increasing bond strength. We found that (i) mineral soil C and N storage was significantly greater under graminoids than shrubs (29.0 ± 1.8 versus 22.5 ± 3.0 kg·C·m−2 and 1.9 ± .12 versus 1.4 ± 1.9 kg·N·m−2), (ii) chemical mechanisms of C storage in the organo-mineral soil fraction did not differ between graminoid and shrub soils, and (iii) weak adsorption to mineral surfaces accounted for 40%–60% of C storage in organo-mineral fractions — a pool that is relatively sensitive to environmental disturbance. Differences in these C pools suggest that rates of C accumulation and retention differ by vegetation type, which could have implications for predicting future soil C pool storage.


2004 ◽  
Vol 34 (7) ◽  
pp. 1538-1542 ◽  
Author(s):  
Heidi Steltzer

Soil carbon (C) and nitrogen (N) pools were measured under the canopy of 29 white spruce (Picea glauca (Moench) Voss) trees and in the surrounding tundra 3 and 6 m away from each tree at three sites of recent forest expansion along the Agashashok River in northwestern Alaska. The aim was to characterize the potential for forest expansion to lead to increased soil C pools across diverse tundra types. Soil C beneath the trees correlated positively with tree age, suggesting that tree establishment has led to C storage in the soils under their canopy at a rate of 18.5 ± 4.6 g C·m–2·year–1. Soil C in the surrounding tundra did not differ from those under the trees and showed no relationship to tree age. This characterization of the soil C pools at the 3-m scale strengthens the assertion that the pattern associated with the trees is an effect of the trees, because tree age cannot explain variation among tundra sampling locations at this scale. Potential mechanisms by which these white spruce trees could increase soil C pools include greater production and lower litter quality.


2012 ◽  
Vol 79 (4) ◽  
pp. 1191-1199 ◽  
Author(s):  
Sarah D. Eisenlord ◽  
Zachary Freedman ◽  
Donald R. Zak ◽  
Kai Xue ◽  
Zhili He ◽  
...  

ABSTRACTFuture rates of anthropogenic N deposition can slow the cycling and enhance the storage of C in forest ecosystems. In a northern hardwood forest ecosystem, experimental N deposition has decreased the extent of forest floor decay, leading to increased soil C storage. To better understand the microbial mechanisms mediating this response, we examined the functional genes derived from communities of actinobacteria and fungi present in the forest floor using GeoChip 4.0, a high-throughput functional-gene microarray. The compositions of functional genes derived from actinobacterial and fungal communities was significantly altered by experimental nitrogen deposition, with more heterogeneity detected in both groups. Experimental N deposition significantly decreased the richness and diversity of genes involved in the depolymerization of starch (∼12%), hemicellulose (∼16%), cellulose (∼16%), chitin (∼15%), and lignin (∼16%). The decrease in richness occurred across all taxonomic groupings detected by the microarray. The compositions of genes encoding oxidoreductases, which plausibly mediate lignin decay, were responsible for much of the observed dissimilarity between actinobacterial communities under ambient and experimental N deposition. This shift in composition and decrease in richness and diversity of genes encoding enzymes that mediate the decay process has occurred in parallel with a reduction in the extent of decay and accumulation of soil organic matter. Our observations indicate that compositional changes in actinobacterial and fungal communities elicited by experimental N deposition have functional implications for the cycling and storage of carbon in forest ecosystems.


2020 ◽  
Vol 29 (2) ◽  
pp. e009
Author(s):  
Cuong Levan ◽  
Hung Buimanh ◽  
Bolanle-Ojo Oluwasanmi Tope ◽  
Xiaoniu Xu ◽  
Thanh Nguyenminh ◽  
...  

Aim of the study: The major objective of this study was to estimate the biomass increment and carbon (C) storage of the main ecosystem components in an age-sequence of three Acacia mangium plantation stands.Area of study: Chang Riec Historical - Cultural Forest, Southeastern region, Vietnam.Material and methods: In order to assess the biomass of different tree components, 36 trees with diameter at breast height ranging from 13.38 to 22.87 cm were harvested from the different aged stands. Biomasses of understory (shrubs and herbs), and litter were also determined. Carbon storage in the trees and understory biomass, litter, and mineral soil (0-50 cm) were determined by analyzing the C content of each compartment.Main results: The biomass in trees, understory vegetation, litter, and ecosystem increased with stand age. Soil C represented 61.99% of the total, aboveground tree biomass C made up 26.73%, belowground tree biomass C accounted for 7.01%, and litter comprised 2.96%, whereas only a small amount (1.30%) was associated with understory vegetation. The average C content of total tree (47.97%) was higher than those of understory and litter. Soil organic C stock in the top 50 cm depth in 4-, 7- and 11-year-old stands of A. mangium were 86.86, 126.88 and 140.94 Mg. C ha-1 respectively. Soil C concentration decreased continually with increasing soil depth. Total C storage of three planted forests ranged from 131.36 to 255.86 Mg. C ha-1, of which 56.09 - 67.61% of C storage was in the soil and 26.88 - 40.40% in the trees.Research highlights: These results suggest that A. mangium is a promising afforestation tree species with fast growing, high biomass accumulation and high C sequestration potential.Keywords: Acacia mangium plantations; Biomass; Ecosystem carbon storage; Age-sequence; Vietnam.


2007 ◽  
Vol 87 (1) ◽  
pp. 93-102 ◽  
Author(s):  
J M Kranabetter ◽  
A M Macadam

The extent of carbon (C) storage in forests and the change in C stocks after harvesting are important considerations in the management of greenhouse gases. We measured changes in C storage over time (from postharvest, postburn, year 5, year 10 and year 20) in logging slash, forest floors, mineral soils and planted lodgepole pine (Pinus contorta var. latifolia) trees from six prescribed-burn plantations in north central British Columbia. After harvest, site C in these pools averaged 139 Mg ha-1, with approximately equal contributions from mineral soils (0–30 cm), forest floors and logging slash. Together these detrital pools declined by 71 Mg C ha-1, or 51% (28% directly from the broadcast burn, and a further 23% postburn), in the subsequent 20 yr. Postburn decay in logging slash was inferred by reductions in wood density (from 0.40 to 0.34 g cm-3), equal to an average k rate of 0.011 yr-1. Losses in forest floor C, amounting to more than 60% of the initial mass, were immediate and continued to year 5, with no reaccumulation evident by year 20. Mineral soil C concentrations initially fluctuated before declining by 25% through years 10 and 20. Overall, the reductions in C storage were offset by biomass accumulation of lodgepole pine, and we estimate these plantations had become a net sink for C before year 20, although total C storage was still less than postharvest levels. Key words: C sequestration, forest floors; coarse woody debris; soil organic matter


2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Witoon Purahong ◽  
Michael Schloter ◽  
Marek J. Pecyna ◽  
Danuta Kapturska ◽  
Veronika Däumlich ◽  
...  

2011 ◽  
Vol 8 (8) ◽  
pp. 2195-2208 ◽  
Author(s):  
A. Kammer ◽  
F. Hagedorn

Abstract. Very few field studies have quantified the different pathways of C loss from decomposing litter even though the partitioning of C fluxes is essential to understand soil C dynamics. Using 0.75 kg m−2 of 13C-depleted leaf (δ13C = −40.8 ‰) and 2 kg m−2 of twig litter (δ13C = −38.4 ‰), we tracked the litter-derived C in soil CO2 effluxes, dissolved organic C (DOC), and soil organic matter of a beech forest in the Swiss Jura. Autotrophic respiration was reduced by trenching. Our results show that mineralisation was the main pathway of C loss from decomposing litter over 1 yr, amounting to 24 and 31 % of the added twig and leaf litter. Contrary to our expectations, the leaf litter C was mineralised only slightly (1.2 times) more rapidly than the twig litter C. The leaching of DOC from twigs amounted to half of that from leaves throughout the experiment (2 vs. 4 % of added litter C). Tracing the litter-derived DOC in the soil showed that DOC from both litter types was mostly removed (88–96 %) with passage through the top centimetres of the mineral soil (0–5 cm) where it might have been stabilised. In the soil organic C at 0–2 cm depth, we indeed recovered 4 % of the initial twig C and 8 % of the leaf C after 1 yr. Much of the 13C-depleted litter remained on the soil surface throughout the experiment: 60 % of the twig litter C and 25 % of the leaf litter C. From the gap in the 13C-mass balance based on C mineralisation, DOC leaching, C input into top soils, and remaining litter, we inferred that another 30 % of the leaf C but only 10 % of twig C could have been transported via soil fauna to soil depths below 2 cm. In summary, over 1 yr, twig litter was mineralised more rapidly relative to leaf litter than expected, and much less of the twig-derived C was transported to the mineral soil than of the leaf-derived C. Both findings provide some evidence that twig litter could contribute less to the C storage in these base-rich forest soils than leaf litter.


2010 ◽  
Vol 7 (2) ◽  
pp. 1575-1602 ◽  
Author(s):  
Y. Carrillo ◽  
E. Pendall ◽  
F. A. Dijkstra ◽  
J. A. Morgan ◽  
J. M. Newcomb

Abstract. Elevated CO2 generally increases soil C pools. However, greater available C concentrations can potentially stimulate soil organic matter (SOM) decomposition. The effects of climate warming on C storage can also be positive or negative. There is a high degree of uncertainty on the combined effects of climate warming and atmospheric CO2 increase on SOM dynamics and its potential feedbacks to climate change. Semi-arid systems are predicted to show strong ecosystem responses to both factors. Global change factors can have contrasting effects for different SOM pools, thus, to understand the mechanisms underlying the combined effects of multiple factors on soil C storage, effects on individual C pools and their kinetics should be evaluated. We assessed SOM dynamics by conducting long-term laboratory incubations of soils from PHACE (Prairie Heating and CO2 Enrichment experiment), an elevated CO2 and warming field experiment in semi-arid, native northern mixed grass prairie, Wyoming, USA. We measured total C mineralization and estimated the size of the labile pool and the decomposition rates of the labile and resistant SOM pools. To examine the role of plant inputs on SOM dynamics we measured aboveground biomass, root biomass, and soil dissolved organic C (DOC). Greater aboveground productivity under elevated CO2 translated into enlarged pools of readily available C (measured as total mineralized C, labile C pool and DOC). The effects of warming on the labile C only occurred in the first year of warming suggesting a transient effect of the microbial response to increased temperature. Experimental climate change affected the intrinsic decomposability of both the labile and resistant C pools. Positive relationships of the rate of decomposition of the resistant C with aboveground and belowground biomass and dissolved organic C suggested that plant inputs mediated the response by enhancing the degradability of the resistant C. Our results contribute to a growing body of literature suggesting that priming is a ubiquitous phenomenon that should be included in C cycle models.


2020 ◽  
Author(s):  
Lucia M. Eder ◽  
Enrico Weber ◽  
Johannes Rousk ◽  
Marion Schrumpf ◽  
Sönke Zaehle

&lt;p&gt;Rising atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations may induce or aggravate nitrogen (N) limitation to plant growth. To overcome this limitation, plants may invest their newly assimilated carbon (C) into N acquiring strategies, such as root growth, root exudation or C allocation to mycorrhizal symbionts. These shifts in C allocation can increase the turnover of soil organic matter by stimulating microbial activity. As these processes are poorly quantified, their net effects on ecosystem C storage remain uncertain.&lt;/p&gt;&lt;p&gt;To gain a better quantitative understanding of these processes, we assessed the effect of elevated CO&lt;sub&gt;2&lt;/sub&gt; on plant C and N allocation in a mesocosm experiment. For four months of one growing season, 64 saplings of Fagus sylvatica L. were grown in a natural beech forest topsoil. Plants were exposed to near ambient (390 ppm) or elevated (560 ppm, eCO&lt;sub&gt;2&lt;/sub&gt;) CO&lt;sub&gt;2&lt;/sub&gt; concentrations at two levels of continuous &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; enrichment (&amp;#948;&lt;sup&gt;13&lt;/sup&gt;C +50 or +150&amp;#8240;). At the end of the experiment, we determined dry biomass, C and N concentrations and isotopic compositions for all leaves, buds, twigs, stems and fine and coarse roots for all plants. For all plants, C and N budgets and the amount of newly incorporated C were evaluated.&lt;/p&gt;&lt;p&gt;We found a positive effect of eCO&lt;sub&gt;2&lt;/sub&gt; on tree growth, with the highest growth response in fine root biomass. In both CO&lt;sub&gt;2&lt;/sub&gt; treatments, newly fixed C was preferentially allocated to roots compared to other plant compartments, but under eCO&lt;sub&gt;2&lt;/sub&gt;, we found a shift in C allocation patterns towards higher belowground C allocation. These results suggest enhanced plant investments into belowground resource acquisition. Decreased N concentrations in all plant organs of these trees under eCO&lt;sub&gt;2&lt;/sub&gt; may indicate plant N limitation and suggest that the effect of increased belowground C allocation was insufficient to fulfil the plants N demand. Still, the observed increase in C allocation to microbial biomass in these soils may be a mechanism to enhance plant N nutrition. CO&lt;sub&gt;2&lt;/sub&gt; concentrations also affected C allocation within the whole plant-soil-system: Under eCO&lt;sub&gt;2&lt;/sub&gt;, more C was stored in tree biomass and less C was stored in soils. Overall, there was no effect of CO&lt;sub&gt;2&lt;/sub&gt; treatment on total mesocosm C. We will discuss these findings with regard to the N mining hypothesis.&lt;/p&gt;


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