Figure 7 - uploaded by Jukka Pumpanen
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(a) Soil CO 2 concentration in O-, A-, B-and C-horizons and (b) soil temperatures in respective horizons in the old forest before clear-cutting and at the clear-cut site.
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... paper III, the automated chambers and manual chambers were compared in situ on forest soil, and with a diffusion box method developed by Widén & Lindroth (2003). The non-flow-through chamber gave ~50% lower efflux values than the flow- through chamber during high efflux in summer (Fig. 7a in III). When compared to known CO 2 effluxes generated artificially and ranging from 0.4 to 0.8 g CO 2 m -2 h -1 , the flow-through chamber gave equal effluxes at the lower end of the range, but overestimated high effluxes by 20%. The non-flow-through chamber underestimated the CO 2 efflux by 30% (Fig. 7b in III). These differences should be ...
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... chamber during high efflux in summer (Fig. 7a in III). When compared to known CO 2 effluxes generated artificially and ranging from 0.4 to 0.8 g CO 2 m -2 h -1 , the flow-through chamber gave equal effluxes at the lower end of the range, but overestimated high effluxes by 20%. The non-flow-through chamber underestimated the CO 2 efflux by 30% (Fig. 7b in III). These differences should be taken into consideration when interpreting the results of this ...
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... -1 in B-horizon and 3860 µmol mol -1 in C-horizon in June and July. However, in O-and A-horizons the concentrations were of the same magnitude than those in the young forest. High concentrations in April were also measured in the old forest, CO 2 concentrations peaking at 14254 µmol mol -1 and 9530 µmol mol -1 in O-and A-horizons, respectively (Fig. 7a.). After clear-cutting the CO 2 concentrations in all soil horizons were substantially lower than before clear- cutting. In O-and A-horizons the average CO 2 concentrations between June and July in 1998 were 29% and 33% lower than those before clear-cutting. In B-and C- horizons the concentration decreased less, 20-26 % respectively. CO ...
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... ( Fig. 8 in II). There was a gradient in CO 2 concentration the concentrations being highest in deeper soil layers throughout the year indicating that there was biological activity in the soil profile all year round (Fig. 6. in III). According to model simulations, most of the CO 2 production occurred in the humus layer throughout the year ( Fig. 7. in II). However, the relative contribution of deeper layers to total respiration was at its highest in late autumn, because of low temperature at the soil surface. The three years studied represented extreme variation concerning soil water content. The late summers of 1997 and 1999 were very dry whereas the summer of 1998 was exceptionally ...
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... years were on the same level (Fig. 7a). The concentration increased in the spring, partly because of increased soil moisture by thawing and formation of ice crust on the soil ...
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... CO 2 concentration decreased significantly in all soil horizons. This is an indication of decreased biological activity in the soil profile. Evidently, the respiration by living roots deceased shortly after clear-cutting resulting in decreased CO 2 concentration especially in O-and A-horizons, where most of the CO 2 production occurred ( Fig. 7 in ...
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... times higher than that of boles during the first 5 years of decomposition. Therefore in the long run, the actual mass losses of the logging residue, roots and stumps are probably much lower than those presented here. On the other hand, the method used for measuring CO 2 effluxes on the clear-cut site seemed to underestimate effluxes even by 30% (Fig. 7, in III). If this underestimation was taken into account, the mass losses of the logging residue, roots and stumps would be higher, but still the decomposition that material would take more than 20 ...
Citations
... There is also a possibility that the chamber measurements underestimate the CO2 efflux. According to Rayment (2000) and Pumpanen (2003) the closed chamber systematically underestimates the CO2 efflux. This is possibly because the actual volume in effect does not include just the volume of the chamber, but also the air filled space in the ground under the chamber (Rayment 2000). ...
Even-aged forests usually act as carbon sinks during most of their rotation. However, after clearcut they become sources of carbon for a period of several years. Applying uneven-aged forest management with selective cuttings will maintain tree cover and reduce the environmental impact on forest floor. The aim of this study was to compare the soil CO2 efflux between uneven-aged and even-aged Norway spruce stands with similar site properties, to investigate the effect of management practices on soil CO2 efflux and its possible correlation with soil environmental and chemical properties. We measured soil CO2 efflux in even- and uneven-aged Norway spruce stands (Picea abies [L.] Karst) in southern Finland during the summer of 2013 using closed chamber method on fixed measuring points. The study included two uneven-aged stands and two even-aged stands (a clearcut site and a mature even-aged stand). Soil moisture and soil temperature were measured at the same time as soil CO2 efflux. Soil cores were collected from the topsoil of each study plot to determine soil carbon and nitrogen concentrations. Mean soil CO2 efflux through the summer was highest in the clearcut plot (0.367 mg m-2 s-1) followed by the uneven-aged stands (0.298 and 0.257 mg m-2 s-1, respectively) and the smallest fluxes were measured in the mature even-aged stand (0.224 mg m-2 s-1). There was no statistically significant difference in soil CO2 efflux between the even- and uneven-aged stands of the same site fertility. Even- and uneven-aged stands did not differ significantly in soil moisture or soil temperature. Soil CO2 efflux increased steadily with soil temperature, whereas increasing soil moisture considerably increased soil CO2 efflux at lower moisture levels but only moderately at higher soil moisture levels. Soil carbon and nitrogen concentration did not differ between the study plots of the same fertility. Uneven-aged structure forestry did not prevent the increase in soil CO2 efflux after cuttings. However, the large variation in soil CO2 efflux rates within the uneven-aged stands suggests that the stand level CO2 efflux can be controlled with the intensity of the cutting.
... The elevated CO 2 flux in the cut areas can be attributed to increased organic input, increase in disturbed soil surface area, and organic material decomposition rate (Mallik and Hu, 1997;Str€ omgren et al., 2016). The decomposition of large amounts of logging slashes and root biomass of cut shrubs and herbs may compensate for the decrease in root and rhizosphere respiration compared to areas without soil treatment (Pumpanen, 2003). In our study, the harvest and tending residues increased the amount of organic matter after clear-cutting. ...
... The physical disturbance of the soil by mixing and burying organic matter into the mineral soil in reforestation plots accelerate the rate of decomposition (Pumpanen, 2003;Levy-Booth et al., 2016), and hence stimulate microbial activity and increase microbial abundance (Kuzyakov, 2006). In our study, the soil disturbance intensity in the treatments varied. ...
Reforestation after clear-cutting is used to facilitate rapid establishment of new stands. However, reforestation may cause additional soil disturbance by affecting soil temperature and moisture, thus potentially influencing soil respiration. Our aim was to compare the effects of different reforestation methods on soil CO2flux after clear-cutting in a Chinese fir plantation in subtropical China: uncut (UC), clear-cut followed by coppicing regeneration without soil preparation (CC), clear-cut followed by coppicing regeneration and reforestation with soil preparation, tending in pits and replanting (CCRP), and clear-cut followed by coppicing regeneration and reforestation with overall soil preparation, tending and replanting (CCRO). Clear-cutting significantly increased the mean soil temperature and decreased the mean soil moisture. Compared to UC, CO2fluxes were 19.19, 37.49 and 55.93 mg m-2h-1higher in CC, CCRPand CCRO, respectively (P < 0.05). Differences in CO2fluxes were mainly attributed to changes in soil temperature, litter mass and the mixing of organic matter with mineral soil. The results suggest that, when compared to coppicing regeneration, reforestation practices result in additional CO2released, and that regarding the CO2emissions, soil preparation and tending in pits is a better choice than overall soil preparation and tending.
... These results support our second hypothesis. Both Mallik and Hu (1997) and Pumpanen (2003) reported that mixing organic matter with mineral soil significantly increased R S rate. In detail, the organic matter decomposition rate was faster in buried sites than left on soil surface (Johansson, 1994;Lundmark-Thelin and Johansson, 1997). ...
... The level and temporal range of plot averages of soil CO2 efflux, from 0.04 to 0.90 gCO2 m -2 h -1 in Huhus and 0.05 to 1.12 gCO2 m -2 h -1 in Mekrijärvi during the snow-free period (Papers I, III), was within the range reported for other boreal Scots pine forests (e.g. Shibistova et al. 2002b;Bhupinderpal-Singh et al. 2003;Pumpanen 2003;Kolari et al. 2009). The snow-free period was covered with over 5000 measurements during three consequent snow-free periods in Huhus, of which the data from two latter years were used to model efflux and thus estimate annual efflux (Paper I). ...
... Ґрунтовий покрив є найбільш заселеною частиною біосфери: в 1 кг ґрунту міститься 500 млрд бактерій, 10 млрд актиноміцетів, 1 млрд грибів, 0,5 млрд мікрофауни (Керженцев, 2006), що забезпечують тісний зв'язок між органічною частиною ґрунту і суміжними резервуарами Карбону (у фітомасі, атмосфері, гідросфері). Фактично, ґрунт виступає обмінним резервуаром С. Співвідношення між виділенням CO2 гетеротрофними організмами і поглинанням CO2 автотрофами визначає напрям і характер змін ґрунтового резервуару Карбону, який, внаслідок знеліснення, перетворюється зі стоку СО2 на джерело його емісії (Pumpanen, 2003). ...
У монографії розглянуті екосистемна роль органічної частини ґрунту та новітні теоретико-методологічні підходи до її дослідження. Головну увагу зосереджено на її лабільних, зокрема легкоокиснювальних і водорозчинних фракціях, компонентах та пулах. На підставі експериментів по вивченню впливу лісогосподарських заходів різної інтенсивності та аграрного використання суміжних післялісових земель (сінокіс та рілля) на структурно-функціональний стан ґрунтового резервуару Карбону органічних сполук (Сорг) показано високу інформативність якісно-кількісних змін «свіжої» високолабільної органічної речовини в оцінці антропопресії. У зв’язку з цим, детально охарактеризовані процеси трансформування лабільного пулу органічної речовини ґрунту в процесі знеліснення, особливості мінералізаційної здатності та дихальної активності ґрунтів лісових і аграрних екосистем, вплив знеліснення на якість та екопротекторну здатність органічних сполук ґрунту, речовинно-енергетичні зміни ґрунтів за різних способів лісокористування та аграрного використання.
У модельних експериментах, за імітування умов глобального потепління клімату, виявлено зменшення термочутливості (Q10) процесу мінералізації органічної речовини і емісії СО2 з ґрунту лісових і післялісових екосистем, що дозволило припустити наявність компенсаторного механізму підтримання балансу Карбону у системі “ґрунт-рослина-атмосфера”, який функціонує за принципом від’ємного зворотного зв’язку (negative feedback).
Для вдосконалення системи екологічного моніторингу на рівні блоку «ґрунт» запропоновано, у разі відбору зразків для аналітичних робіт, виокремити контактний із зовнішнім середовищем шар ґрунту товщиною 0-5 см як його «стрес-чутливу зону», – найбільш вразливу до різних впливів, які порушують едафічну рівновагу.
Для екологів, ґрунтознавців і спеціалістів в цій галузі.
... Ґрунтовий покрив є найбільш заселеною частиною біосфери: в 1 кг ґрунту міститься 500 млрд бактерій, 10 млрд актиноміцетів, 1 млрд грибів, 0,5 млрд мікрофауни (Керженцев, 2006), що забезпечують тісний зв'язок між органічною частиною ґрунту і суміжними резервуарами Карбону (у фітомасі, атмосфері, гідросфері). Фактично, ґрунт виступає обмінним резервуаром С. Співвідношення між виділенням CO2 гетеротрофними організмами і поглинанням CO2 автотрофами визначає напрям і характер змін ґрунтового резервуару Карбону, який, внаслідок знеліснення, перетворюється зі стоку СО2 на джерело його емісії (Pumpanen, 2003). ...
... The categories are broad enough to classify all land areas in most countries, and to accommodate differences in national land-use classification systems and can be identified using approaches provided by the Intergovernmental Panel on Climate Change (IPCC) (IPCC, 2006a). Based on the studies of IPCC (2006a) and Pumpanen (2003), the calculation method for estimating GHG emissions during site preparation are proposed as follows: Table 1, CO 2 efflux from boreal forest DOM before site preparation is 1026 g CO 2 e/m 2 /yr. The total amount of carbon in the logging residue at steady state was about 1.7 kg C/m 2 . ...
... Emissions from the movement of DOM: DOM is composed of dead wood and litter that is mainly from logging residues. At the place where the logging residue and root litter are left on the site after site preparation, the estimated annual effluxes are nearly 4730 g CO 2 e/m 2 during the first three years and 478 g CO 2 e/m 2 in later years (Pumpanen, 2003). Given that the total amount of carbon in logging residue at steady state is approximately 1.7 kg C/m 2 , the annual effluxes from DOM account for approximately 76.4% (first three years) and 7.7% (other years) of the logging residue pool. ...
... Note: The total amount of carbon in the soil and logging residue simulated by the model at steady state was about 5.5 kg C/m 2 and 1.7 kg C/m 2 . Data source: Pumpanen, 2003. Emissions from soil movement: Although both organic and inorganic forms of carbon are found in soils, land-use conversion typically has a larger impact on organic carbon stocks (IPCC, 2006a). ...
Pavement rehabilitation is carbon intensive and the choice of pavement type is a critical factor in controlling greenhouse gas (GHG) emissions. The existing body of knowledge is not able to support decision-making on pavement choice due to a lack of consensus on the system boundaries, the functional units and the estimation periods. Excessive data requirements further inhibit the generalization of the existing methodologies for design evaluation at the early planning stage. This study proposes a practical life-cycle GHG estimation approach, which is arguably effective to benchmark pavement emissions given project bid tabulation. A set of case studies conducted for this study suggest that recycled asphalt pavement (e.g., foam stabilized base (FSB), and warm mix asphalt (WMA)) would prevent up to 50% of GHGs from the initial construction phase. However, from a life-cycle perspective, pavement emissions are dictated largely by the traffic characteristics and the analysis period for the use phase. The benefits from using recycled materials (e.g., FSB) are likely to diminish if the recycled products do not perform as well as those properly proportioned with less recycled materials, or if the recycled materials are locally unavailable. When the AADT reaches 10,000, use phase releases more than 97% of the life cycle emissions and the emissions difference among alternative designs will be within 1%.
... It describes the diffusive flux between soil air and atmosphere, which is the primary mechanism for gas exchange (Glí nski and St ˛ epniewski, 1985). Furthermore, top soil CO 2 concentration can be used as integrative parameter to describe soil aeration (SchackKirchner, 1994; Gaertig et al., 2002; Pumpanen, 2003). Depending on soil respiration, i.e., respiration of roots and microorganisms, and soil gas diffusivity, the CO 2 concentration in the topsoil is up to 100 times higher than in the atmosphere (Gaertig et al., 2002; Pumpanen, 2003 ). ...
... Furthermore, top soil CO 2 concentration can be used as integrative parameter to describe soil aeration (SchackKirchner, 1994; Gaertig et al., 2002; Pumpanen, 2003). Depending on soil respiration, i.e., respiration of roots and microorganisms, and soil gas diffusivity, the CO 2 concentration in the topsoil is up to 100 times higher than in the atmosphere (Gaertig et al., 2002; Pumpanen, 2003 ). Elevated CO 2 concentration in the soil atmosphere can be attributed to restricted gas exchange rather than to high soil respiration (Schack-Kirchner, 1994; Gaertig, 2001; Gaertig et al., 2002). ...
... The highest soil respiration fluxes in the northern hemisphere have typically been measured in July and August (Högberg et al., 2001;Pumpanen et al., 2004b). In our study, the soil CO 2 fluxes ranged from 0.36 to 0.67 g m −2 h −1 , and are thus comparable to rates measured in similar forest ecosystems, from 0.01 g CO 2 m −2 h −1 up to 3.60 g CO 2 m −2 h −1 (Boone et al., 1998;Gulledge and Schimel, 2000;Pumpanen, 2003). The removal of wind-damaged timber decreased instantaneous CO 2 flux from the soil surface/forest floor, whereas the highest instantaneous fluxes were measured on the areas with total canopy destruction and wind thrown material left on site. ...
Storms can turn a great proportion of forests’ assimilation capacity into dead organic matter because
of windthrow and thus its role as a carbon sink will be diminished for some time. However, little is
known about the magnitude or extent to which storms affect carbon efflux. We compared soil CO2 fluxes
in wind-thrown forest stands with different time periods since a storm event, and with different management
practices (deadwood cleared or left on-site). This study examined changes in soil CO2 efflux
in two windthrow areas in north-eastern Estonia and one area in north-western Latvia, which experienced
severe wind storms in the summers of 2001, 2002 and 1967, respectively. We measured soil CO2
fluxes in stands formerly dominated by Norway spruce (Picea abies L. Karst.) with total and partial canopy
destruction (all trees or roughly half of the trees in stand damaged by storm), in harvested areas (material
removed after the wind storm) and in control areas (no damage by wind). Removal of wind-damaged
material decreased instantaneous CO2 flux from the soil surface. The highest instantaneous fluxes were
measured in areas with total and partial canopy destruction (0.67 g CO2m−2 h−1 in both cases) compared
with fluxes in the control areas (0.51 g CO2m−2 h−1), in the new storm-damaged areas where the material
was removed (0.57 g CO2m−2 h−1) and in the old storm-damaged area where wood was left on site
(0.55 g CO2m−2 h−1). The only factor affecting soil CO2 flux was location of the measuring collar (plastic
collar with diameter 100mm, height 50mm) – either on undamaged forest ground or on the uprooted
tree pit, where the mineral soil was exposed after disturbance. New wind-thrown stands where residues
are left on site would most likely turn to sources of CO2 for several years until forest regeneration reaches
to substantial assimilation rates. New wind-thrown stands where residues are left on site would most
likely tend to have elevated CO2 fluxes for several years until forest regeneration reaches to substantial
assimilation rates. However, forest managers might be concerned about the amounts of CO2 immediately
released into the atmosphere if the harvested logs are burned.
... The results in this study would in some cases also be applicable to unburnt clear-cuts, in which the soil temperature is normally higher than in uncut forests (Pumpanen, 2003;Grenon et al., 2004;Hashimoto and Suzuki, 2004). Temperatures as high as 40 1C were measured in the litter-soil interface in a clear-cut in North Carolina (Seastedt and Crossley, 1981) while temperatures above 30 1C were measured 3.5 cm below ground in a clear-cut in Washington (Fowler and Anderson, 1987). ...
... Temperatures as high as 40 1C were measured in the litter-soil interface in a clear-cut in North Carolina (Seastedt and Crossley, 1981) while temperatures above 30 1C were measured 3.5 cm below ground in a clear-cut in Washington (Fowler and Anderson, 1987). The insulating effect of the organic layer in clear-cuts of a boreal forest will normally keep the temperature in the lower part of the humus layer well below that measured as lethal in this study (Pumpanen, 2003). However, some heat-induced mortality of soil animals in clear-cuts cannot be excluded, especially in patches where the heatabsorbing black humus layer is directly exposed to sunlight. ...
Forest fires markedly reduce the abundance of surface-dwelling soil animals; animal densities also decline in soil layers underlying the char layer. The aim of the present study was to determine lethal temperatures for different species within the more abundant microarthropod groups in boreal forests, namely Collembola, Protura, Mesostigmata and Oribatida. In the laboratory, forest soil humus containing naturally occurring microarthropods was heated in plastic bags to avoid desiccation. Each sample was heated to one of 11 different temperatures between 20 and 60 °C for 1, 4, or 12 h. At the 1-h exposure, 36 °C was the highest temperature tolerated before significant decreases in numbers were detected. The corresponding temperatures after 4- and 12-h exposures were 34 °C for Oribatida and 30–32 °C for Collembola, Protura and Mesostigmata, respectively. Individual species responded differently, and the most heat-tolerant species within Oribatida was Tectocepheus velatus (40 °C at 4-h exposure) while Friesea mirabilis and Mesaphorura sp. (36 °C at 4-h exposure) were the most tolerant within Collembola. During a forest fire, temperatures higher than those tolerated by the investigated groups and species may well be reached.
