Mangrove carbon budget in dynamic urban areas

Transcription

1 International Summer Water Resources Research School Dept. of Water Resources Engineering, Lund University Mangrove carbon budget in dynamic urban areas By Tove Juhl Andersen

2 Abstract One of the most efficient carbon sink aquatic ecosystem on the planet is the mangrove. Mangroves are coastal wetlands that exist in tropical and subtropical areas all over the world. In China they are distributed in five provinces in the south east part of the country. In addition to their high potential as carbon sinks, they also contribute with many ecological functions. Among others they provide habitat to many species, filter runoff, improve water quality and protect land against flooding and wind. However, in the past 50 years about one third of the world s mangroves have been destroyed due to development of fishery, agriculture and aquaculture and mangroves are therefore one of the most threatened ecosystems on the planet. In order to change this trend, mangrove reforestation programs have been initiated in many countries. The aim of this project is to compare the carbon concentration in sediment from the native species Kandelia obovata with the non native species Sonneratia apetala in Futian National Nature Mangrove Reserve in the city of Shenzhen. By collecting samples of sediments of different depths, the sediment can be analyzed. In order to collect sediment samples, a 50cm long soil coring sword with a 50 cm extension arm was used. When analyzing the samples they were firstly dried in order to find the bulk density. By using a 2-mm filter, gravel was removed and the gravel weight was subtracted from the bulk density to obtain pure soil bulk density. After this, the entire sample was ground in order to pass through a 250 µm filter. Finally, in order to make a carbon analysis, subsamples of mg were analyzed for carbon concentration using a Vario EL CHN autoanalyzer. Due to lack of time, samples from 2012 were used. The results showed that the native species Kandelia obovata had the highest concentration of carbon in the sediment. However, other factors might affect the results such as the age of the forests. In this study we have been looking at two mature forests but with an age difference of 50 years. It is not possible to find Sonneratia apetala in Shenzhen that is older than 20 years since it is a non-native species that fast planted in the beginning of the 1990s. In order to get even more reliable results it would probably be good to analyze samples from forests with the same age to see if this affects the carbon content in the sediment. The carbon concentration was highest in the top 40 cm of the soil both for Sonneratia apetala and for Kandelia obovata and decreases with the depth from approximately 50 cm down in the soil. This correlates well with the fact that most mangrove roots are in the top layer of the soil and that the carbon rises to the top layer after decomposition of organic material. The results in this project give important and interesting knowledge that should be considered in future reforestation programs. However, even though the significance of the results is good it would be good to combine them with historical data and more field studies from a longer time period in order to get even more reliable results. Keywords: Mangrove, Coastal ecosystems, Carbon sequestration, Reforestation, Global warming 2

3 Table of Contents 1. Introduction Aim Theory Mangrove in China Blue Carbon Carbon storage Previous studies Species Sonneratia apetala Kandelia obovata Description of the sampling site Shenzhen site Description of the excursion site Hainan site Field sampling Method Calculations Results Analysis and Conclusion Acknowledgement References Appendix Appendix 1 Table with soil bulk density and carbon percentage Appendix 2 Table with avg soil bulk density, avg C (%), layer avg C and total C

4 1. Introduction The whole world is facing a global climate change that is partly due to humans over consuming fossil fuels and emitting an unhealthy amount of CO 2. As China is a growing economy, infrastructure, cities and industries are developing rapid (Fu Liu & Prabhu 2012). The development does not only need to be economically beneficial, but also sustainable from an environmental point of view. Usually when it comes to decreasing the amount of emitted CO 2, new and sustainable technology in the transport and energy sectors are considered to be a solution to the problem. However, it is easy to forget that our planet consist of carbon consuming oceans, coastal wetlands and other ecosystems which play an important role in storing carbon and therefore could be part of the solution. One of the most efficient carbon sink aquatic ecosystems on the planet is the mangrove (Lunstrum & Chen 2014). Mangroves are coastal wetlands that exist in tropical and subtropical areas all over the world. In China they are distributed in five provinces in the south east part of the country. In addition to their high potential as carbon sinks, they also contribute with many ecological functions. Among others they provide habitat to many species, filter runoff, improve water quality and protect land against flooding and wind. (Zhang 2014). In the past 50 years about one third of the world s mangroves have been destroyed due to development of fishery, agriculture and aquaculture (UNFCCC 2012) Mangroves are one of the most threatened ecosystems on the planet (Lunstrum & Chen 2014). In order to change this trend, mangrove reforestation programs have been initiated in many countries. According to Chen 1 the non native species Sonneratia apetala has often been used for reforestation because it is believed to have a great ability to store carbon due to high rates of biomass growth and because it grows faster than e.g. the native species Kandelia obovata. Today the interest in mangroves as carbon sinks has increased and they are often included as an important part of reforestation programs. (Lunstrum & Chen 2014). Mangroves occupy less than 0.1% of the Earth s continent s surface but they are responsible for 8-15 % of the carbon deposited in coastal sediments and 10-11% of the total export of terrestrial carbon to the ocean (Liu et al. 2013). Many studies have showed the importance of mangroves ability as carbon sinks. However, they have mostly focused on carbon quantity import, export and production per year instead of researching the mangroves capability to trap carbon. (Liu et al. 2013). Such researches, on a national level, are necessary in order to design management policies and restoration programs for mangroves in China. 1.1 Aim The aim of this project is to compare the carbon concentration in sediment from the native species Kandelia obovata with the non native species Sonneratia apetala. This will be determined by analyzing data from field studied that have been carried out in Futian National Nature Mangrove Reserve in the city of Shenzhen in Another purpose of this project is to learn and understand how the field studies are carried out. This knowledge will be maintained by a field excursion to Dongzhaigang National Nature Mangrove 1 Chen Luzhen, Professor at Xiamen University, interviews during the period june 24 th to july 16 th.

5 Reserve in Haikou on the island Hainan. However, the field samples in Dongzhaigang National Nature Mangrove Reserve will not be analyzed due to lack of time. These samples are therefore only used as illustrative examples. The main question that will be answered in this report is: - Is there a difference in the concentration of carbon in the sediment from Kandelia obovata and Sonneratia apetala in the sediment at Futian National Nature Mangrove Reserve? This study is a small part of a bigger project where the goal is to submit a report of mangrove as carbon sinks to Shenzhen government and provide suggestions of how to protect mangroves. 5

6 2. Theory 2.1 Mangrove in China China has in recent history, just like many other countries, experienced radical losses of mangrove forest. Only one third of the historical extent of mangroves still exists and the total area of mangroves in China today is approximately 22,700 ha. Due to this, the Chinese government started to investigate the possibilities of mangrove reforestation in the early 1990s. Year 2002 more than 10 % of the mangrove area had been replanted. (Lunstrum & Chen 2014). There are 24 species of true mangrove and 12 species of semi-mangrove in China. They are found in five provinces; Hainan, Guangxi, Guangdong, Fujian and Zheijang (Zhang 2014). Mangroves grow in environments that can be hard on other species. They are highly adaptable and can tolerate high salinity, tidal water and extreme weather such as tsunamis. (National Geographic 2007, Zhang 2014) However, factors such as climate, salinity and tidal fluctuation can still limit the distribution of mangroves. (Mangrove Action Project 2014). 2.2 Blue Carbon Carbon persevered in aquatic wetlands is sometimes referred to as blue carbon. This term is commonly used in studies investigating the carbon storage in especially sediments and soils of mangroves. An increase of studies in the subject can be seen due to mangroves disproportionate small area compared to their high ability to store carbon, which make them interesting from a global climate change point of view. (Alongi 2014). Coastal wetlands sequesters carbon up to hundreds times faster than terrestrial forests. Governments and non-governmental organizations are putting a lot of effort into reforestation of mangroves with the hope that it can help minimizing the global climate change. According to Alongi this is a simplification of the problem and global expansion of mangrove forests is unlikely to notably level out the imbalance of the global climate change (2014). Compared with the annual emissions of CO 2, the function of mangroves as carbon sinks is small. Even if the area of mangroves was doubled so that the function as a carbon sink globally would be 24 Tg C y -1, this is a small number compared to the annual global emissions that currently lies at 30.6 Gt C y -1. (Alongi 2014). 2.3 Carbon storage The carbon storage in mangrove sediment is estimated by taking the difference of carbon losses, from e.g. export, mineralization and consumption, and the rate of annual accumulation. What is left is assumed to be preserved. Mangroves in China accumulate soil carbon at rate of 200 g C m -2 y -1. This is a high number compared to other forests, probably due to high human impact. (Alongi 2014). The soil carbon concentration of mangroves is globally estimated to 8.5 % when assuming that the carbon concentration increases as the mangrove grows older. However, the concentration can vary a lot when looking at different studies where the sediment samples have been taken at different or unknown depths. (Lunstrum & Chen 2014). Most mangroves have their roots in the top 50 cm layer of the soil. When organic material is decomposed the carbon will rise to the top layer of the soil. According to Chen 1, both of these two factors are the reasons that the carbon content in mangrove sediment is highest in the top layer. 6

7 Due to the deforestation of mangroves the concerns of how much carbon is being emitted to the atmosphere is increasing. Changes in the soil chemistry have appeared caused by clearing of the forest for industrial and agricultural purposes and emission rates of CO 2 have increased rapidly. (Alongi 2014). According to Alongi the mangrove contribution of carbon sequestration in the global coastal ocean has a sequestration rate of g C m -2 y -1, a global sequestration rate of 24 Tg C y -1 and a potential global loss of Tg C y -1 (2014). 2.4 Previous studies The research of carbon sequestration in Mangroves sediment is a field that often needs many years of sampling and evaluations in order to get good and reliable results. Lunstrum and Chen (2014) published an article in 2014 where they had made field studies on how the carbon concentration in the top layer of the sediment differed for Kandelia obovata and Sonneratia apetala during a time period of 6 years. The results, however, showed that the increased carbon concentration for the two species did not differ significantly even though Sonneratia apetala had much greater biomass (Lunstrum and Chen 2014). In a research by Wang et al. (2013) it was found that there was a significant correlation between soil organic carbon (SOC) and vegetation biomass in the upper 0-50 cm of the soil layer. This could be a positive indication that an increase in vegetation biomass will lead to an increase of mangrovederived SOC in the upper half meter soil. (Wang et al. 2013). According to Ren et al. (2008) Sonneratia apetala, a non-native species in China has a very high biomass carbon accumulation rate compared to other native species. In the same research it was found that carbon content in the soil of Sonneratia apetala was higher compared to surrounding native species. Therefore it is also suggested that the rate of carbon accumulation in the soil is higher compared to native species. (Lunstrum and Chen 2014). 2.5 Species The species that have been analyzed in this project are Sonneratia Apetala and Kandelia obovata. The samples collected in Dongzhaigang National Nature Mangrove Reserve were taken from one area with pure Sonneratia apetala and one area with pure Kandelia obovata Sonneratia apetala Sonneratia apetala is a member of the Lythraceae family. The species is native in India, Bangladesh and Myanmar, and has been introduced to southern parts of China. Even though it is a fast growing species, the Sonneratia apetala is mainly decreasing. (Kathiresan et al 2010). 7

8 Figure 1. Sonneratia apetala. Picture taken in Dongzhaigang National Nature Mangrove Reserve Sonneratia apetala grow up to 20 meter but is usually between meter high (Kathiresan et al 2010). It can be distinguished by its round and green fruits (see figure 1) that has given the species its English name, Mangrove apple (Macau Biodiversity 2014a) Kandelia obovata Kandelia obovata is a member of the Rhizophoraceae family. The species can usually be found in southern China, Vietnam, Taiwan and Japan. The distribution is decreasing in north of Japan but the population trend is mainly decreasing. (Duke et al 2010). Figure 2. Kandelia obovata (Manko Waterbird and Wetland Center 2014) Kandelia obovata can be recognized by its pen-like droppers that hang down from the tree branches (see figure 2). It reproduces quickly and is found in intertidal regions in the downstream estuarine zone (Macau Biodiversity 2014b, Duke et al 2010). The species grows relatively slow, 1.5 meters in 5 years, and generally grows up to 3 meters (Duke et al 2010). The English name of the species is simply Kandelia (Macau Biodiversity 2014b) 8

9 2.6 Description of the sampling site Shenzhen site Futian National Nature Mangrove Reserve is located in the city of Shenzhen in the province Guangdon. The reserve is separated from the urban area by a large levee. The amount of nutrients, heavy metals and other pollutants in the area is high due to sewage and industry, but the physical disturbance from humans is limited due to strict regulation and limitation to visit and access the area. (Lunstrum & Chen 2014). Figure 3. Map of Futian National Nature Mangrove Reserve. The climate in the area is sub-tropical and much influenced by the monsoon. The mean annual temperature is 22.5 C and it is very humid. The mangroves in the Futian reserve are spread in a meters long strip along the coast (figure 3) and consist of both naturally colonized forests and also reforestation. The dominant species of mangroves in the area are Kandelia obovata, Aegicerias corniculatum and Avicennia marina. There are also smaller areas of Sonneratia apetala and Sonneratia caseolaris. S. caseolaris is native in the Hainan province whereas Sonneratia apetala is non-native. These two species have been planted in patches near the native forests since the beginning of (Lunstrum & Chen 2014). 2.7 Description of the excursion site Hainan site Dongzhaigang National Nature Mangrove Reserve is located in Haikou city in the north of the island Hainan (see figure 4). The mangrove site that will be used for sampling in this study is located west of the Dongzhaigang Estuary and has a total area of 1,733 ha. There are 23 different mangrove species in this area. The dominant species are Bruguiera sexangula, Bruguiera gymnorrihiza, Avicennia marina, Kandelia obovata and Rhizophora stylosa. 9

10 Figure 4. Map of Dongzhaigang National Nature Mangrove Reserve. (Whats on Sanya 2010) 10

11 3. Field sampling 3.1 Method Three squares with the size of 10m*10m were set up for two areas with the dominant species Sonneratia apetala and Kandelia obovata. In order to collect sediment samples, a 50cm long soil coring sword with a 50 cm extension arm was used (figure 5). By using this equipment, samples from 0-50 cm and cm could be obtained. Figure 5 (right) Professor Chen using the soil coring sword Figure 6 and 7. Soil core sword with sediment (left) and cutting ring (right) In order to divide the different core sample sections representing different depth, a 98 cm 3 cutting ring was used. The cutting ring helped making samples representing depths at 0-10 cm, cm, cm, cm, cm and cm (figure 6 and figure 7). All collected samples were dried at 60 C in order to find a constant weight. The depth-interval samples were weighed to obtain the bulk density. Bulk density is a density measurement used for porous material and gives the soils mass per unit volume of the total soil material, including the volume of open and closed pores (Houston, Tranter & Miller 2014). All samples were ground by using a mortar and pestle in order to remove large roots, sticks and shells. By using a 2-mm filter, gravel was removed and the gravel weight was subtracted from the 11

12 bulk density to obtain pure soil bulk density. After this, the entire sample was ground in order to pass through a 60-mesh (250 µm) filter. Finally, in order to make a carbon analysis, subsamples of mg were analyzed for carbon concentration (percentage of dry soil mass) using a Vario EL CHN autoanalyzer. 3.2 Calculations All the gathered data were compiled in excel in order to calculate the different parameters necessary for the results. To determine the carbon content in each soil layer, the bulk density and the soil carbon concentration of each layer were used. In order to find the total carbon storage of 1 m 3, the different soil layers carbon content was added together. Equation 1-3 below, show the equations that were used to find carbon percentage, bulk density and layer average carbon content. In order to find the carbon percentage per wet weight (C %) equation 1 was used: In order to find the bulk density (BD) in g soil/m 3, equation 2 was used: (equation 1) (equation 2) In order to find the Layer average carbon content (LA C) in g/m 3, equation 3 was used: (equation 3) The average soil dry bulk density (Avg soildbd), the average carbon concentration (Avg C (%)) and the total carbon (g/m 2 ) were as seen in equation 4-5. The results of these calculations can be seen in appendix 1 and appendix 2. (equation 4) (equation 5) (equation 6) In order to estimate the carbon content in the soil taken from areas of Sonneratia apetala and Kandelia obovata, the average carbon content in each layer (Layer average) for the two different species was calculated, see table 1 and table 2 in Results. Finally, the average carbon content per m 3 is found by taking the average of the total carbon content for each species. 12

13 4. Results Table 1 and table 2 show the Layer average for the different average depths for Sonneratia apetala (table 1) and for Kandelia obovata (table 2). Table 1. Layer average and standard deviation for Sonneratia apetala at the top 1 meter layer of the soil. Average depth (m) Layer average (g/m 2 ) Standard deviation (g/m 2 ) 0, , ,075 0, , ,196 0, , ,084 0, , ,384 0, , ,9483 0, , ,7602 Table 2. Layer average and standard deviation for Kandelia obovata at the top 1 meter layer of the soil. Average depth (m) Layer average (g/m 2 ) 0, ,856 0, ,38 0, ,4 454,0987 0, ,8 1751,345 0, , ,751 0, , ,79 Standard deviation (g/m 2 ) In table 3 the final average carbon content per m 3 can be seen (bold numbers). Table 3. An overview of the two species ages, average soil bulk density, average carbon content in percentage, total carbon content, the average carbon content per m 3 and the standard deviation. Age of the trees (years) Species 20 Sonneratia apetala 20 Sonneratia apetala 20 Sonneratia apetala 70 Kandelia obovata 70 Kandelia obovata 70 Kandelia obovata Average Soil dry bulk density (g/cm 3 ) Average C (%) Total C (g/m 2 ) (1 m deep) Average C content (g/m 3 ) Standard deviation 1,01 0, , , ,53 1,05 0, ,83 1,16 0, ,10 0,79 1, , , ,35 0,76 2, ,54 0,63 2, ,72 13

14 In figure 8, the results shown in table 1 and table 2 are plotted against each other. By that it is possible to determine which species has the highest carbon concentration in the sediment and at what depth. The graph also shows the significance and the variation of the values Depth (cm) Sonneratia apetala Kandelia obovata C concentration (g m -3 ) Figure 8. Distribution of carbon in the sediment of Sonneratia apetala and Kandelia obovata at different depths in the soil. 14

15 5. Analysis and Conclusion Table 3 shows that the average carbon content per cubic meter is for Sonneratia apetala and for Kandelia obovata. The standard deviation seems high at first. However, earlier studies show that the carbon content in mangrove sediment can vary a lot. Considering the high variations of carbon that is usually seen in mangrove sediment the size of the standard deviation is normal. The graph in figure 8 shows that the carbon concentration is highest in the top 40 cm of the soil both for Sonneratia apetala and for Kandelia obovata. From 40 cm to 85 cm down in the soil, the concentration of carbon decreases for both of the species. For Sonneratia apetala the highest concentration of carbon will be found in the top layer of the soil, while for Kandelia obovata the highest carbon concentration is found approximately 15 cm down in the soil. This correlates well with the fact that most mangrove roots are in the top layer of the soil and that the carbon rises to the top layer after decomposition of organic material. Figure 8 also shows that the carbon concentration is higher in the soil of Kandelia obovata through the whole depth compared to Sonneratia apetala. However, the study by Lunstrum and Chen (2014) that was completed during a six years period showed that the difference over time between the two species did not differ significantly. It is important, to remember that other factors might affect the results such as e.g. the age of the forests. In this study we have been looking at two mature forests but with an age difference of 50 years. It is not possible to find Sonneratia apetala in Shenzhen that is older than 20 years since it is a non-native species that was planted in the beginning of the 1990s. In order to get even more reliable results it would probably be good to analyze samples from forests with the same age to see if this affects the carbon content in the sediment. Considering the fact that Sonneratia apetala grows faster and gets bigger and higher compared to Kandelia obovata, according to the study made by Wang et al. (2013) the amount of carbon in the sediment of Sonneratia apetala should be higher than Kandelia obovata. This is however not the case in our results. Ones again the reason for this might depend on other factors such as time period of sampling and age. A source of error in this project could be that the method used is very dependent on the collection of samples being accurate and precise. When penetrating the soil core sword into the soil this might make the sample slightly more compact and therefore result in an inaccurate bulk density. However, since the same soil core sword is used for both species, the errors are probably not very big. To conclude, the results show that Kandelia obovata has a higher concentration of carbon in the sediment compared to Sonneratia apetala in Futian National Nature Mangrove Reserve. This is important and interesting knowledge that should be considered in future reforestation programs. However, even though the significance of the results is good it would be good to combine them with historical data and more field studies from a longer time period in order to get even more reliable results. 15

16 6. Acknowledgement I would like to thank Professor Luzhen Chen for having me in part of her important project and for bringing me on an exciting fieldtrip to Dongzhaigang National Nature Mangrove Reserve. I would also like to thank all the students at Xiamen University for their hospitality and for taking so good care of me during my stay at Xiamen University. I would especially like to thank the students Lin Ting, Naxu Hu, Congjiao Peng and Xudong for the cooperation in the project, laughs and good talks about Chinese culture and Mangroves. Further, I would like to thank Lund University, Xiamen University and the companies Tyréns, Sweco and Sveriges Ingenjörer for making this project and cultural experience possible. 16

17 7. References Alongi, D. M. (2014) Carbon Cycling and Storage in Mangrove Forests. Annu. Rev. Mar. Sci : Duke, N., Kathiresan, K., Salmo III, S.G., Fernando, E.S., Peras, J.R., Sukardjo, S. & Miyagi, T. (2010) Kandelia obovata. The IUCN Red List of Threatened Species. Version Avaliable at: [ ] Fu C., Liu J. & Prabhu R. (2012) China and UN-REDD Programme, what they can do together to move the REDD+ agenda forward? UNEP POLICY SERIES ECOSYSTEM MANAGEMENT. POLICY BRIEF Houston A., Tranter G. & Miller I. (2014) Bulk Density. Avaliable at: [ ] Kathiresan, K., Salmo III, S.G., Fernando, E.S., Peras, J.R., Sukardjo, S., Miyagi, T., Ellison, J., Koedam, N.E., Wang, Y., Primavera, J., Jin Eong, O., Wan-Hong Yong, J. & Ngoc Nam, V. (2010) Sonneratia apetala. The IUCN Red List of Threatened Species. Version Avaliable at: [ ] Liu H., Ren H., Hui D., Wang W., Liao B. &Cao Q. (2013) Carbon stocks and potential carbon storage in the mangrove forests of China. Elsevier, Journal of Environmental Management 133 (2014) Lunstrum, A. & Chen, L. (2014) Soil carbon stocks and accumulation in young mangrove forests. Elsevier, Soil Biology & Biochemistry 75 (2014) Mangrove Action Project. (2014) Distribution. Avaliable at: [ ] Macau Biodiversity. (2014a) Sonneratia apetala. Avaliable at: [ ] Macau Biodiversity. (2014b) Kandelia obovata. Avaliable at: [ ] Manko Waterbird and Wetland Center. (2014) Kandelia obovata. Avaliable at: [ ] Mesa. (2014) Gallery-Mangrove species. Avaliable at: [ ] National Geographic. (2007) Mangroves Forests of the Tide. Avaliable at: [ ] Pendleton L, Donato DC, Murray BC, Crooks S, Jenkins WA, et al. (2012) Estimating Global Blue Carbon Emissions from Conversion and Degradation of Vegetated Coastal Ecosystems. PLoS ONE 7(9): e doi: /journal.pone UNFCCC. (2012) Update on developments in research activities relevant to the needs of the Convention, including on the long-term global goal; and information on technical and scientific aspects of emissions and removals of all greenhouse gases from coastal and marine ecosystems. Subsidiary Body for Scientific and Technological Advice. Thirty-sixth session, Bonn, May

18 Whats on Sanya. (2010) Dongzhaigang: 1st & largest mangrove natural reserve in China. Available at: [ ] Zhang, Y. (2014) Lecture: Global Climate Change and Vulnerability of Coastal Wetland Ecosystems. Lecture june 25 th, College of the Environment & Ecology Xiamen University. Wang, G., Guan, D., Peart, M.R., Chen, Y. & Peng, Y. (2013) Ecosystem carbon stocks of mangrove forest in Yingluo Bay, Guangdong Province of South China. Elsevier, Forest Ecology and Management 310 (2013)

19 8. Appendix 8.1 Appendix 1 Table with soil bulk density and carbon percentage The gathering of Soil Dry Bulk Density and the carbon concentration in percentage. Increment depth Species and age (years) Depth (cm) Soil DBD (g/m3) C (%) x (cm) 10 Sa ,20 1,402 1, Sa ,78 1, Sa ,17 1, Sa ,12 0, Sa ,07 0, Sa ,73 0, Sa ,36 2, Sa ,33 1, Sa ,87 1, Sa ,39 0, Sa ,05 0, Sa ,71 0, Sa ,93 1, Sa ,23 1, Sa ,30 0,2 20 Sa ,14 0, Sa ,97 0, Sa ,31 0, Ko ,05 2,672 4, Ko ,41 4, Ko ,24 3, Ko ,77 2, Ko ,74 0, Ko ,29 0, Ko ,43 3, Ko ,52 6, Ko ,17 2, Ko ,09 1, Ko ,53 1, Ko ,15 1, Ko ,58 5, Ko ,69 8, Ko ,25 3,04 20 Ko ,32 2, Ko ,34 0, Ko ,55 0,101 19

20 8.2 Appendix 2 Table with avg soil bulk density, avg C (%), layer avg C and total C. The gathering of average soil dry bulk density, the average carbon concentration in percentage, the layer average carbon content and the total carbon. Avg SoilDBD(g/cm 3 ) Avg C (%) Layer Avg C(g/m 2 ) Total C (g/m 2 ) (1 m deep) 1,01 0, , , , , , , ,72 1,05 0, , , , , , , ,51 1,16 0, , , , , , , ,87 0,79 1, , , , , , , ,99 0,76 2, , , , , , , ,30 0,63 2, , , , , , , ,48 20