Diurnal and seasonal dynamics of soil respiration in desert shrubland of Artemisia Ordosica on Ordos Plateau of Inner Mongolia, China

The diurnal and seasonal dynamics of soil respiration in the A. ordosica shrubland on Ordos Plateau were investigated in the growing season （May-October） of 2006 and their environmental driving factors were also analyzed, Results indicated that diurnal dynamics of soil respiration rate and its temperature dependence showed some discrepancy in two different growth stages （the vegetative growth stage and the reproductive growth stage）. During the vegetative growth stage, the diurnal variation of soil respiration was slight and not correlated with the daily temperature change, but during the reproductive growth stage, the daily respiration variation was relatively large and significantly correlated with the diurnal variation of air and soil temperature. In the growing season, the peak value of soil respiration occurred at July and August because of the better soil water-heat conditions and their optimal deployment in this period. In the shrubland ecosystem, precipitation was the switch of soil respiration pulses and can greatly increase soil respiration rates after soil rewetting. Moreover, the soil respiration rates in the growing season and the air temperature and soil surface water content were closely correlated （p〈0.05） each other. The stepwise regression model indicated that the variation of soil surface moisture accounted for 41.9% of the variation in soil respiration （p〈0.05）.     

Effects of adding water on seasonal variation of soil nitrogen availability under sandy grasslands in semi-arid region

Water is usally thought of a limiting factor for the restoration of semi-arid ecosystem. In the growing season of 2006, a study was conducted to determine the effects of modeling precipitation on seasonal patterns in concentrations of soil-available nitrogen and to describe the seasonal patterns in soil nitrogen availability and seasonal variation in the rates of net nitrogen mineralization of topsoil at Daqinggou ecological station in Keerqin sand lands, Inner Mongolia Autonomous Region, China. Manipulation of water （80 mm） was designed to be added to experiment plots of sandy grasslands in dry season. Water addition （W） treatment and control （CK） treatment were separately taken in six replications and randomly assigned in 12 plots （4 m×4 m for each） with 2-m buffers betweens. Results showed that the content of soil inorganic nitrogen and net nitrogen mineralization rate were not affected by adding water in sandy grassland of Keerqin sand lands. Net ni- trogen mineralization rates ranged from 0.5μg·g^-1,month^-1 to 4 μg.g^-1.month^-1. The highest values of soil inorganic nitrogen and net nitrogen mineralization occurred on October 15 in control plots. The seasonal changes of soil inorganic nitrogen contents exhibited ＂V＂ shape pattern that was related to seasonal patterns of soil ammonium-N （ascending trend） and nitrate-N transformation （descending trend）.     

Wildland fires and moist deciduous forests of Chhattisgarh,India: divergent component assessment

We studied moist deciduous forests of Chhattisgarh, India （1） to assess the effect of four levels of historic wildland fire frequency （high, medium, low, and no-fire） on regeneration of seedlings in fire affected areas during pre and post-fire seasons, （2） to evaluate vegetation struc- ture and diversity by layer in the four fire frequency zones, （3） to evalu- ate the impact of fire frequency on the structure of economically impor- tant tree species of the region, and （4） to quantify fuel loads by fire fre- quency level. We classified fire-affected areas into high, medium, low, and no-fire frequency classes based on government records. Tree species were unevenly distributed across fire frequency categories. Shrub density was maximum in zones of high fire frequency and minimum in low- frequency and no-fire zones. Lower tree density after fires indicated that regeneration of seedlings was reduced by fire. The population structure in the high-frequency zone was comprised of seedlings of size class （A） and saplings of size class （B）, represented by Diospyros melanoxylon, Dalbergia sissoo, Shorea robusta and Tectona grandis. Younger and older trees were more abundant for Tectona grandis and Dalbargia sis- soo after fire, whereas intermediate-aged trees were more abundant pre- fire, indicating that the latter age-class was thinned by the catastrophic effect of fire. The major contributing components of fuel load included duff litter and small woody branches and twigs on the forest floor. Total fuel load on the forest floor ranged from 2.2 to 3.38 Mg/ha. The netchange in fuel load was positive in high- and medium-frequency fire zones and negative under low- and no-fire zones. Repeated fires, how- ever, slowly reduced stand stability. An ecological approach is needed for fire management to restore the no-fire spatial and temporal structure of moist deciduous forests, their species composition and fuel loads. The management approach should incorporate participatory forest manage- ment. Use of c     

Short-term effects of nitrogen deposition on soil respiration components in two alpine coniferous forests,southeastern Tibetan Plateau

Nitrogen (N) deposition to alpine forest ecosystems is increasing gradually, yet previous studies have seldom reported the effects of N inputs on soil CO2 flux in these ecosystems. Evaluating the effects of soil respiration on N addition is of great significance for understanding soil carbon (C) budgets along N gradients in forest ecosystems. In this study, four levels of N (0, 50, 100, 150 kg N ha^-1 a^-1) were added to soil in a Picea baifouriana and an Abies georgei natural forest on the Tibetan Plateau to investigate the effect of the N inputs on soil respiration. N addition stimulated total soil respiration (Rt) and its components including heterotrophic respiration (Rh) and autotrophic respiration (Ra);however, the promoted effects declined with an increase in N application in two coniferous forests. Soil respiration rate was a little greater in the spruce forest (1.05 μmol CO2 m^-2 s^-1) than that in the fir forest (0.97 μmol CO2 m^-2 s^-1). A repeated measures ANOVA indicated that N fertilization had significant effects on Rt and its components in the spruce forest and Rt in the fir forest, but had no obvious effect on Rh or Ra in the fir forest. Rt and its components had significant exponential relationships with soil temperature in both forests. N addition also increased temperature sensitivity (Q10) of Rt and its components in the two coniferous forests, but the promotion declined as N in put increased. Important, soil moisture had great effects on Rt and its components in the spruce forest (P<0.05), but no obvious impacts were observed in the fir forest (P>0.05). Following N fertilization, Ra was significantly and positively related to fine root biomass, while Rh was related to soil enzymatic activities in both forests. The mechanisms underlying the effect of simulated N deposition on soil respiration and its components in this study may help in forecasting C cycling in alpine forests under future levels of reactive N deposition.     

Herbaceous species diversity in relation to fire severity in Zagros oak forests,Iran

Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For this purpose neighboring burned and unburned areas were selected with the same plant species and ecological conditions. The data were collected from areas subjected to different fire severities. Overall 6 treatments were considered with respect to fire severity and the mi-crosites of inside and outside of oak sprout clumps including： unburned inside and outside of sprout clumps （Ni and No）, inside of sprout clumps that burned with high fire severity （H）, inside of sprout clumps that burned with moderate fire severity （M）, outside of sprout clumps that burned with low fire severity （OH and OM）. Different herbaceous com-position was observed in the unburned inside and outside of oak sprout clumps. The species diversity and richness were increased in treatments burned with low and moderate fire severity. However, in treatment burned with high fire severity （H）, herbaceous cover was reduced, even-ness was increased, and richness and diversity were not significantly changed. We concluded that besides the microsites conditions in forest, fire severity is an inseparable part of the ecological effect of fire on her-baceous composition.     

Effects of selective logging on tree diversity and some soil characteristics in a tropical forest in southwest Ghana

We investigated the effects of selective logging disturbances on tree diversity and soil characteristics in the Bia Conservation Area in southwest Ghana.The study was conducted in unlogged,29-35 years post-logged and swamp forests using ten 25 m×25 m plots.In total,we identified 310 individual trees belonging to 87 species.Mean ShannonWeiner index was highest in the post-logged forest but there were no significant differences in tree density,dominance,or DBH size class distributions between these forests.Soil physical properties such as pH and bulk density up to 30 cm depth were similar in the two of forests In terms of soil nutrient status,available P,exchangeable K and total N contents were all similar in the unlogged and post-logged forests.Our findings suggest that the effects of logging on tree diversity are comparatively long-term,in contrast to its short-term effects on some top soil physical and chemical characteristics.     

Effects of phenolic acids on soil nitrogen mineralization over successive rotations in Chinese fir plantations

Phenolic acids are secondary metabolites of plants that significantly affect nutrient cycling processes.To investigate such effects,the soil available nitrogen(N)content,phenolic acid content,and net N mineralization rate in three successive rotations of Chinese fir plantations in subtropical China were investigated.Net N mineralization and nitrification rates in soils treated with phenolic acids were measured in an ex situ experiment.Compared with first-rotation plantations(FCP),the contents of total soil nitrogen and nitrate in second(SCP)-and third-rotation plantations(TCP)decreased,and that of soil ammonium increased.Soil net N mineralization rates in the second-and third-rotation plantations also increased by 17.8%and 39.9%,respectively.In contrast,soil net nitrification rates decreased by 18.0%and 25.0%,respectively.The concentrations of total phenolic acids in the FCP soils(123.22±6.02 nmol g^-1)were 3.0%and 17.9%higher than in the SCP(119.68±11.69 nmol g^-1)and TCP(104.51±8.57 nmol g^-1,respectively).The total content of phenolic acids was significantly correlated with the rates of net soil N mineralization and net nitrification.The ex situ experiment showed that the net N mineralization rates in soils treated with high(HCPA,0.07 mg N kg^-1 day^-1)and low(LCPA,0.18 mg N kg^-1 day^-1)concentrations of phenolic acids significantly decreased by 78.6%and 42.6%,respectively,comparing with that in control(0.32 mg N kg^-1 day^-1).Soil net nitrification rates under HCPA and LCPA were significantly higher than that of the control.The results suggested that low contents of phenolic acids in soil over successive rotations increased soil net N mineralization rates and decreased net nitrification rates,leading to consequent reductions in the nitrate content and enhancement of the ammonium content,then resulting in enhancing the conservation of soil N of successive rotations in Chinese fir plantation.     

Forecasting the development of boreal paludified forests in response to climate change: a case study using Ontario ecosite classification

Background:Successional paludification,a dynamic process that leads to the formation of peatlands,is influenced by climatic factors and site features such as surficial deposits and soil texture.In boreal regions,projected climate change and corresponding modifications in natural fire regimes are expected to influence the paludification process and forest development.The objective of this study was to forecast the development of boreal paludified forests in northeastern North America in relation to climate change and modifications in the natural fire regime for the period 2011–2100.Methods:A paludification index was built using static(e.g.surficial deposits and soil texture)and dynamic(e.g.moisture regime and soil organic layer thickness)stand scale factors available from forest maps.The index considered the effects of three temperature increase scenarios(i.e.+1°C,+3°C and+6°C)and progressively decreasing fire cycle(from 300 years for 2011–2041,to 200 years for 2071–2100)on peat accumulation rate and soil organic layer(SOL)thickness at the stand level,and paludification at the landscape level.Results:Our index show that in the context where in the absence of fire the landscape continues to paludify,the negative effect of climate change on peat accumulation resulted in little modification to SOL thickness at the stand level,and no change in the paludification level of the study area between 2011 and 2100.However,including decreasing fire cycle to the index resulted in declines in paludified area.Overall,the index predicts a slight to moderate decrease in the area covered by paludified forests in 2100,with slower rates of paludification.Conclusions:Slower paludification rates imply greater forest productivity and a greater potential for forest harvest,but also a gradual loss of open paludified stands,which could impact the carbon balance in paludified landscapes.Nonetheless,as the thick Sphagnum layer typical of paludified forests may protect soil organic layer from drought and deep burns,a significant proportion of the territory has high potential to remain a carbon sink.     

Effect of fire severity on physical and biochemical soil properties in Zagros oak(Quercus brantii Lindl.) forests in Iran

Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares,where we sampled soils in areas that were classified by fire severity: low(LS), high(HS) and medium severity(MS),and unburned(UB), which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide,and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchangecapacity, accessible phosphorus, accessible potassium,bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physical–chemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned.     

Response of soil respiration to a severe drought in Chinese Eucalyptus plantations

Extreme droughts can adversely affect the dynamics of soil respiration in tree plantations. We used a severe drought in southwestern China as a case study to estimate the effects of drought on temporal variations in soil respiration in a plantation of Eucalyptus globulus. We documented a clear seasonal pattern in soil respiration with the highest values(100.9 mg C–CO_2 m~(-2)h~(-1)) recorded in June and the lowest values(28.7 mg C–CO_2 m~(-2)h~(-1)) in January. The variation in soil respiration was closely associated with the dynamics of soil water driven by the drought. Soil respiration was nearly twice as great in the wet seasons as in the dry seasons. Soil water content accounted for 83–91% of variation in soil respiration, while a combined soil water and soil temperature model explained 90–99% of the variation in soil respiration. Soil water had pronounced effects on soil respiration at the moisture threshold of 6–10%. Soil water was strongly related to changes in soil parameters(i.e., bulk density, p H,soil organic carbon, and available nitrogen). These strongly influenced seasonal variation in soil respiration. We found that soil respiration was strongly suppressed by severe drought. Drought resulted in a shortage of soil water which reduced formation of soil organic carbon, impacted soil acid–base properties and soil texture, and affected soil nutrient availability.     

Characteristics of runoff and sediment generation of forest vegetation on a hill slope by use of artificial rainfall apparatus

We studied the impact of forest vegetation on soil erosion,surface runoff, and sediment generation by using field simulated rainfall apparatus. We measured runoff and sediment generation of five 4.5 × 2.1m runoff plots (a bare soil as a control; two Pinus tabulaeformis forestplots and two Platycladus orientalis forest with row spacing of 1 m × 1m and 1.5 m × 1.5 m, respectively) in Beijing Jiu Feng National ForestPark under three rainfall intensities (0.42, 0.83, 1.26 mm per minute).Forest vegetation significantly reduced soil erosion and sediment yield.Mean total runoff volume in the four tree stand plots was 93% of that inthe control plot, demonstrating the limited effectiveness of forest vegetation in runoff control. With increasing rainfall intensity, runoff reductionin forest plots declined from 28.32% to 2.1%. Similar trends in runoff coefficient and the relationship between runoff volume and rainfall duration was observed. Mean total sediment yield and mean sediment yield reduction rate under different treatments was 55.05% and 43.17% of those in the bare soil control plot, respectively. Rainfall intensity playedan important role in runoff and sediment generation processes, and had agreater impact on runoff than on soil erosion and sediment generation.When considering several factors in runoff and sediment transport processes, the P. tabulae form plot with row spacing at 1 × 1 m had a greater effect on soil and water conservation than did other forested plots.     

Three-source partitioning of soil respiration by ~(13)C natural abundance and its variation with soil depth in a plantation

Partitioning soil respiration into three components is vital to identify CO_2 sink or source and can help us better understand soil carbon dynamics. However, knowledge about the influences of soil depth and the priming effect on soil respiration components under field has been limited. Three components of soil respiration(root respiration, rhizomicrobial respiration and basal respiration) in a plantation in the hilly area of the North China were separated by the 13 C natural abundance method. The results showed that the average proportions of rhizomicrobial respiration, root respiration and basal respiration at the 25–65 cm depths were about 14, 23 and 63 %, respectively. Three components of soil respiration varied with soil depth, and root respiration was the main component of soil respiration in deeper soil. The priming effect was obvious for the deep soil respiration, especially at the 40–50 cm depth. Thus, depth and priming effect should be taken into account to increase the accuracy of estimations of soil carbon flux.     

Impacts of low-intensity prescribed fire on microbial and chemical soil properties in a Quercus frainetto forest

Prescribed fire is a common economical and effective forestry practice, and therefore it is important to understand the effects of fire on soil properties for better soil management. We investigated the impacts of low-intensity prescribed fire on the microbial and chemical properties of the top soil in a Hungarian oak(Quercus frainetto Ten.) forest. The research focused on microbial soil parameters(microbial soil respiration(RSM), soil microbial biomass carbon(Cmic) and metabolic quotient(qCO_2) and chemical topsoil properties(soil acidity(pH),electrical conductivity(EC), carbon(C), nitrogen(N), C/N ratio and exchangeable cations). Mean annual comparisons show significant differences in four parameters(C/N ratio,soil pH, Cmic and qCO_2) while monthly comparisons do not reveal any significant differences. Soil pH increased slightly in the burned plots and had a significantly positive correlation with exchangeable cations Mg, Ca, Mn and K.The mean annual C/N ratio was significantly higher in the burned plots(28.5:1) than in the control plots(27.0:1). The mean annual Cmic(0.6 mg g~(-1)) was significantly lower although qCO_2(2.5 lg CO_2–C mg Cmic h~(-1)) was significantly higher, likely resulting from the microbial response to fire-induced environmental stress. Low-intensity prescribed fire caused very short-lived changes. The annual mean values of C/N ratio, pH, Cmic and qCO_2 showed significant differences.     

Decomposition of labile and recalcitrant coniferous litter fractions affected by temperature during the growing season

Temperate coniferous forest soils are considered important sinks of soil organic carbon(C).Fresh C inputs may,however,affect soil microbial activity,leading to increased organic matter decomposition and carbon dioxide production.Litter consists of labile and recalcitrant fractions which are thought to be utilized by distinct microbial communities and at different rates during the growing season.In this study,we incubated the whole litter(LC+RC),the labile(LC) and the recalcitrant(RC)fractions with the coniferous soil at two temperatures representing spring/autumn(10℃) and summer(20℃)for one month.Soil respiration and microbial community composition were regularly determined using phospholipid fatty acids as biomarkers.The LC fraction greatly increased soil respiration at the beginning of the incubation period but this effect was rather short-term.The effect of the RC fraction persisted longer and,together with the LC+RC fraction,respiration increased during the whole incubation period.Decomposition of the RC fraction was more strongly affected by higher temperatures than decomposition of the more labile fractions(LC and LC+RC).However,when we consider the relative increase in soil respiration compared to the dH_2 O treatment,respiration increased more at a lower temperature,suggesting that available C is more important for microbial metabolism at lower temperatures.Although C was added only once in our study,no changes in microbial community composition were detected,possibly because the microbial community is adapted to relatively low amounts of additional C such as the amounts naturally found in litter.     

Application of pre-emergence herbicides in poplar nursery production

In addition to pests and diseases, weeds are a major problem in poplar nursery production. The possibilities of herbicide application in juvenile poplar growth were researched, taking into account that weeds are one of the main limiting factors. The following pre-emergence herbicides were tested: acetochlor, S-metolachlor, metribuzin,oxifluorfen, and dimethenamid during two vegetation seasons at two locations, which differed by the soil physicochemical characteristics. The study results show that the number of weeds on sample plots was significantly reduced by the tested herbicides when compared to control plots. The highest reduction in the number of weeds was achieved using the herbicides acetochlor and metribuzin. However, metribuzin showed a phytotoxic effect on sandy soil. Metribuzin application is recommended only on the soils with higher contents of organic matter, where the phytotoxic effect was absent. Acetochlor, S-metolachlor, oxifluorfen, and dimethenamid were not phytotoxic to poplars and can be used for weed suppression in the production of poplar plants.     

Germination characteristics and diversity of soil seed banks and above-ground vegetation in disturbed and undisturbed oak forests

The destruction of natural ecosystems is an important issue in many parts of the world. In the west of Iran, a vast area of the Zagros Mountain range is covered by typical vegetation including several rare plant species, of which many are currently considered endangered by anthropogenic activities. Despite the important role of soil seed banks to help conserve these degraded plant communities, the floristic studies in the Zagros forests have only focused on above- ground vegetation. In this study, the characteristics of soil seed banks and above-ground vegetation were examined at two forest sites： an undisturbed control （Un） and a disturbed （D） site. The objectives of this study were 1） to investigate the diversity of above-ground vegetation and soil seed banks in disturbed and undisturbed forests, 2） to examine the soil properties and the germination characteristics of the soil seed bank in disturbed and undisturbed oak forests and 3） to estimate the potential of soil seed banks in the restoration of disturbed sites. The results show that soil properties between Un and D sites were significantly different with higher values of pH, NH4-N, N~o,, CEC, OC, clay and canopy percentage in the Un site than in the D site. The Simpson diversity, Margalef richness and evenness indices differed significantly between sites, either for the soil seed banks or the above-ground vegetation. After a period of 26 weeks, the germination speed and the mean daily number of germinants were significantly different between Un and D sites. Without other conservation measures, soil seed banks alone cannot result in a full recovery after severe disturbances in the oak forests of Zagros.     

Effects of biochar and litter on carbon and nitrogen mineralization and soil microbial community structure in a China fir plantation

To investigate the effects of biochar addition(1 or 3%)to the soil of a China fir plantation with or without litter,we conducted a 90-day incubation experiment.We also studied the C and N dynamics and the microbial community structure of the soil.In soil without litter,the application of biochar at a rate of 3%significantly decreased CO2 emissions,while addition of 1%biochar had no effect.Biochar application did not affect the net N mineralization rate but significantly reduced the NH4?concentration after 90 days.In litter-enriched soil,biochar application had no significant effect on total CO2 emissions;however,application of 3%biochar significantly reduced the net N mineralization rate.Biochar application to soil with or without litter immediately reduced the dissolved organic carbon(DOC)concentration independent of the application rate,which was primarily due to sorption of DOC by the biochar.Phospholipid fatty acid analysis demonstrated that both concentrations of added biochar to soil(with or without litter)altered the soil microbial community structure at the end of incubation,although the effect of biochar was not as strong as the effect of time or litter application.The effect of biochar addition alone on microbial community structure was inconsistent over time.Litter added to soil significantly increased fungi and reduced Gram-positive bacteria.In the presence of litter,biochar applied at both 1%and 3%significantly increased(p<0.05)the proportion of actinomycete only at day 90.Our results indicate biochar as a potentially effective measure for C sequestration in the test soil of a China fir plantation,even in the presence of litter.     

Subsurface accumulation of CaCO_3 and Cl~- from groundwater under black locust and poplar plantations

When conditions are similar,more water evaporates from forest plantations than herbaceous vegetation,thereby affecting hydrological fluxes and ion transport in the soil.The vertical distribution of CaCO3 and Cl^-ions shifts due to afforestation.The effect of groundwater depth and clay content were studied in the Great Hungarian Plain where forest area has been increasing for decades by analyzing soil and groundwater samples from stands of black locust(Robinia pseudoacacia,11 plots)and poplar(Populus spp.,11 plots).All study sites contained one herbaceous(control)and one or more forested plots.CaCO3 and Cl^-ions accumulated in the soil profile in greater quantities under tree cover than in the controls.The scale of this process largely depended on the species and on soil and ion properties.Under black locust,Cl^-accumulated between 1.3 and 6.3 m,with a maximum difference of 0.3 pCl unit(pCl is Cl^-activity,the negative of the logarithm to base 10 of the concentration of the chloride ion,determined using an ion-selective electrode,it is a dimensionless quantity.),while the difference in CaCO3 accumulation was at most 3.5%in some layers,compared to control plots.This result may be explained by the difference in the mobility of Ca+and Cl^-ions.Different mechanisms were noticeable under poplar plantations due to their higher water uptake:Cl-accumulation was detected below 0.9 m to the groundwater with a maximum difference of 0.5 pCl units,while CaCO3 accumulation was continuous at depths of 2.3–6.8 m with a maximum difference of 8.4%,compared to the controls.With increasing clay content,there was a discernible effect on CaCO3 and Cl-accumulation under black locust,but not observed under poplars.These differences were explained by the differences in water uptake mechanisms and root patterns of the two species and the different mobility of Ca2^+and Cl-ions.     

Soil respiration in paludified forests of European Russia

Soil respiration studies in paludified forests of the European part of Russia are quite rare in comparison with those of open peat bogs, which make long-term observations in this region highly relevant. In this study,soil CO_2 emissions were measured by the close chamber method in different microlandscapes of paludified forests.For four summer seasons with different environments, soil respiration ranged from 1078 to 248 mg CO_2 m~(-2) h~(-1) in a paludified spruce forest site with coarse woody debris to659–820 mg CO_2 m~(-2) h~(-1) in a paludified boggy pine forest. The most intensive soil respiration was observed during the hot summer of 2013 and the lowest in the hot and humid summer of 2016. Annual total soil CO_2 emissions in paludified forests in 2015–2016 were approximately 2000–3000 g CO_2 m~(-2). During the year, the lowest CO_2 emission values were observed from November to April(14–84 mg CO_2 m~(-2) h-1) and the maximum were in July and August(522–1205 mg CO_2 m-2 h-1). The contributions of CO_2 emissions in the cold November–Aprilperiod were 6–8.5%. The impacts of temperature on soil respiration were higher(r~2= 0.45–0.57) than those of groundwater levels(r~2= 0.17–0.49). Soil respiration in the paludified spruce forest and in the pine bog generally were higher than emissions from ecosystems with similar hydrothermal conditions in the boreal zone.