Coniferous Forest Ecosystems Research Articles

Seasonal patterns of fine root dynamics and their contribution to net primary production in hinoki cypress (Chamaecyparis obtusa) and konara oak (Quercus serrata) forests

Key messageFine root and litterfall are major contributor of NPP and fine root production may reflect forest productivity in a warm-temperate forest in Japan.Forest ecosystems play an important role as the major carbon sink on land, with fine root dynamics and litterfall representing major carbon fluxes. The objectives of this research were to estimate NPP including annual fine root production values, to investigate fine root dynamics and the relationships between above– and belowground organs in konara oak (Quercus serrata) and hinoki cypress (Chamaecyparis obtusa) forests. Litterfall was collected seasonally for 1 year from June 2013. The ingrowth core method and the sequential soil core method were applied with a root litterbag experiment to estimate fine root (< 2 mm) production (FRP), mortality (FRM), and decomposition (FRD) for 1 year (from 2013 to 2014), using the continuous inflow estimate method and the simplified decision matrix. The total NPP ranged from 8.2 to 13.9 (t ha− 1 yr− 1), and the sum of aboveground litterfall and FRP accounted for 60% of the total NPP on average, confirming the significance of above- and belowground litter for the forest NPP as a source of detritus for the decomposer system. In hinoki cypress stand, fine root biomass peaked in the end of winter while fine root necromass showed the highest peak in late summer. In konara oak stand, only very fine root (< 0.05 mm) biomass and necromass demonstrated significant seasonal patterns. The seasonal patterns of fine root production did not differ between forest types and root diameter classes. We found a possible relationship between above- and belowground production and fine root production tended to be high in productive forests. This study improves our understanding of different patterns of carbon dynamics between temperate broadleaved and coniferous forest ecosystems.

Degradative Capacity of Two Strains of Rhodonia placenta: From Phenotype to Genotype

Brown rot fungi, such as Rhodonia placenta (previously Postia placenta), occur naturally in northern coniferous forest ecosystems and are known to be the most destructive group of decay fungi, degrading wood faster and more effectively than other wood-degrading organisms. It has been shown that brown rot fungi not only rely on enzymatic degradation of lignocellulose, but also use low molecular weight oxidative agents in a non-enzymatic degradation step prior to the enzymatic degradation. R. placenta is used in standardized decay tests in both Europe and North America. However, two different strains are employed (FPRL280 and MAD-698, respectively) for which differences in colonization-rate, mass loss, as well as in gene expression have been observed, limiting the comparability of results. To elucidate the divergence between both strains, we investigated the phenotypes in more detail and compared their genomes. Significant phenotypic differences were found between the two strains, and no fusion was possible. MAD-698 degraded scots pine more aggressively, had a more constant growth rate and produced mycelia faster than FPRL280. After sequencing the genome of FPRL280 and comparing it with the published MAD-698 genome we found 660,566 SNPs, resulting in 98.4% genome identity. Specific analysis of the carbohydrate-active enzymes, encoded by the genome (CAZome) identified differences in many families related to plant biomass degradation, including SNPs, indels, gaps or insertions within structural domains. Four genes belonging to the AA3_2 family could not be found in or amplified from FPRL280 gDNA, suggesting the absence of these genes. Differences in other CAZy encoding genes that could potentially affect the lignocellulolytic activity of the strains were also predicted by comparison of genome assemblies (e.g., GH2, GH3, GH5, GH10, GH16, GH78, GT2, GT15, and CBM13). Overall, these mutations help to explain the phenotypic differences observed between both strains as they could interfere with the enzymatic activities, substrate binding ability or protein folding. The investigation of the molecular reasons that make these two strains distinct contributes to the understanding of the development of this important brown rot reference species and will help to put the data obtained from standardized decay tests across the globe into a better biological context.

Repeated fire shifts carbon and nitrogen cycling by changing plant inputs and soil decomposition across ecosystems

AbstractFires shape the biogeochemistry and functioning of many ecosystems, and fire frequencies are changing across much of the globe. Frequent fires can change soil carbon (C) and nitrogen (N) storage by altering the quantity and chemistry of plant inputs through changes in plant biomass and composition as well as the decomposition of soil organic matter. How decomposition rates change with shifting inputs remains uncertain because most studies focus on the effects of single fires, where transient responses may not reflect responses to decadal changes in burning frequencies. Here, we sampled seven sites exposed to different fire frequencies. In four of the sites, we intensively sampled both soils and plant communities across four ecosystems in North America and Africa spanning tropical savanna, temperate coniferous savanna, temperate broadleaf savanna, and temperate coniferous forest ecosystems. Each site contained multiple plots burned frequently for 33–61 years and nearby plots that had remained unburned over the same period replicated at the landscape scale. Across all sites, repeatedly burned plots had 25–185% lower bulk soil C and N concentrations but also 2–10‐fold lower potential decomposition of organic matter compared to unburned sites. Soil C and N concentrations and extracellular enzyme activities declined with frequent fire because fire reduced both plant biomass inputs into soils and dampened the localized enrichment effect of tree canopies. Examination of soil extracellular enzyme activities revealed that fire decreased the potential turnover of organic matter in the forms of cellulose, starch, and chitin (P &lt; 0.0001) but not polyphenol and lignin (P = 0.09), suggesting a shift in soil C and N cycling. Inclusion of δ13C data from three additional savanna sites (19–60 years of altered fire frequencies) showed that soil C losses were largest in sites where estimated tree inputs into soils declined the most (r2 = 0.91, P &lt; 0.01). In conclusion, repeated burning reduced C and N storage, consistent with previous studies, but fire also reduced potential decomposition, likely contributing to slower C and N cycling. Trees were important in shaping soil C and N responses across sites, but the magnitude of tree effects differed and depended on how tree biomass inputs into soil responded to fire.

Heavy metals content in soils of Western Siberia in relation to international soil quality standards

Russian soil quality standards (maximum permissible concentrations) exist only for Mn, Pb and V out of the many heavy metals (HMs) indicative of soil pollution resulting from hydrocarbon mining. This paper presents a comparative analysis of the total content of Ba, Cr, Cu, Ni and Zn as well as Mn, Pb and V in background soils of Western Siberia (Russia) in relation to the wider range of available internationally recognised assessment criteria. The criteria used include the increase in abundance of elements relatively to the upper part of the continental earth's crust, their levels in background soils of other countries and their threshold concentration values for soils of residential and/or agricultural areas in soil quality standards (SQSs) of Netherlands, Germany, the USA and Canada. Specified countries have similar soils and background concentrations of HMs and well-developed methodologies for soil quality assessment. It is concluded that Cu, Ni and Zn levels in West-Siberian background soils are harmless for an ecosystem and human health, while Ba, Cr, Mn, Pb and V concentrations in some of the soils studied are above threshold values (ThVs) and, therefore, require special attention through further assessment. The studied Retisols, Phaeozems and Chernozems of Western Siberia are characterized by the following range of mean concentrations (mg kg−1) of HMs in topsoil: Ba 373–1360, Cr 5–212, Cu 5–100, Mn 50–1800, Ni 7–100, Pb 5–35, V 5–180, and Zn 10–135. In preliminary assessment of contaminated soils within a coniferous forest and forest-steppe ecosystems of Western Siberia, it is most suitable to use the following national ThVs for HMs (mg kg−1): Canadian Pb (45), German Ni (140) and Cr (400) and Dutch Cu (96) and, considering the local geochemical background (especially for the folic horizon of Retisols), it is also appropriate to use Russian Mn (1500), Canadian Zn (200) and Dutch Ba (890). An eluvial pattern of vertical differentiation is typical for total Cr, Cu, Ni, Pb, Zn in Retisols, Ni and Pb in Phaeozems and Cr, Ni and Pb in Chernozems. In topsoil of background landscapes at Western Siberia, total Mn (in all soils studied), Cu (in Phaeozems), Zn (in Phaeozems and Chernozems), as well as mobile Mn (in Retisols and Phaeozems), Ni (in Retisols) and Zn (in Phaeozems) accumulates.

Production, decomposition and nutrient contents of litter in subtropical broadleaved forest surpass those in coniferous forest, Meghalaya

Litter plays a crucial role in forest ecosystem functioning as its production and decomposition govern the pools and fluxes of forest nutrient cycling. The release of nutrients through litterfall and decomposition influences forest productivity. Therefore, these two factors are considered to be important indicators of forest ecosystem health. Such processes vary across different ecosystem types because of natural as well as anthropogenic factors. Hence, studying such processes would help in better understanding and management of forest ecosystems. Litter production and decomposition rates between a broadleaved and a coniferous forest ecosystem of Meghalaya in Northeast India were compared. We selected six subtropical broadleaved forest stands in Muthlong, Ialong, Nongbah, Mukhla, Nongkrem and Mawnai, and six adjacent coniferous forest stands dominated by pine. We estimated leaf litter production, decomposition and nutrient release, and analyzed the nitrogen and phosphorus contents in the litter of both the forest types. The study revealed that litter production and decomposition rates, and the litter nitrogen and phosphorous contents were significantly higher in the broadleaved forest compared to the pine forest. The variability in the litter characteristics was greater in the broadleaved forest compared to the coniferous forest indicating that the former is functionally more dynamic than the latter. Such dynamism in the broadleaved forest could be an important factor for providing greater ecological services compared to the coniferous forest, which nevertheless requires an in-depth study.

Rainfall Partitioning in Chinese Pine (Pinus tabuliformis Carr.) Stands at Three Different Ages

Chinese pine (Pinus tabuliformis Carr.) is the main forest species in northern China, with the potential to dramatically affect biotic and abiotic aspects of ecosystems in this region. To discover the rainfall partitioning patterns of different growth periods of Chinese pine forest, we studied the throughfall (Tf), stemflow (Sf) and canopy interception (I) in three stand ages (40-, 50-, 60-year-old) in Liaoheyuan Natural Reserve of Hebei Province during the growing seasons of 2013 and 2014, and analyzed effect of rainfall amount, rainfall intensity, and canopy structure on rainfall partitioning in Chinese pine forest. The results showed that throughfall decreased with the stand age, accounting for 78.8%, 74.1% and 66.7% of gross rainfall in 40-, 50- and 60-year-old Chinese pine forests, respectively. Canopy interception, on the other hand, increased with the stand age (20.4%, 24.8%, and 32.8%, respectively), while the pattern in stemflow was less clear (0.8%, 1.1%, and 0.6%, respectively). As rainfall intensity increased, the Tf and Sf increased and I declined. Additionally, our results showed that leaf area index (LAI) and the diameter at breast height (DBH) increased with age in Chinese pine stands, probably explaining the similar increase in canopy interception (I). On the other hand, the mean leaf angle, openness, gap fraction all decreased with the stand age. Stepwise regression analysis showed that the rainfall amount and LAI were the major determinants influencing the rainfall partition. Our study highlights the importance of stand age in shaping different forest canopy structures, and shows how age-related factors influence canopy rainfall partitioning. This study also significantly adds to our understanding the mechanisms of the hydrological cycle in coniferous forest ecosystems in northern China.

Оценка компонентов нижних ярусов растительного покрова в антропогенно нарушенных березняках Красноярской лесостепи

The vegetation cover characteristics of anthropogenically disturbed birch stands of Krasnoyarsk forest-steppe are studied. The research purpose is to study the current state of under story vegetation cover of the birch stands, which have been exposed to recreational and anthropogenic impacts for a long time, as well as to assess the degree and nature of its changeover the 12-year period since the last research. The studies were carried out on the sample plots laid out in mixed herbs birch stands. Cenosises are characterized by V–VI age classes,II–IV quality classes, and 0.6–0.9 density of stocking. The birch stands are located in the main transfer of Krasnoyarsk industrial emissions. Phytocenoses were under significant anthropogenic and recreational impact for a long time. At each facility, 30 sites (1 m2 each) were laid, where species composition, horizontal and vertical structure, projective cover and occurrence of undergrowth and forest live cover species were assessed. The comparative analysis of floristic lists was performed using the Sorensen-Czekanowski coefficient (Ksc). The degree of species diversity was estimated by using the Shannon index; the degree of recreational transformation – synanthropization index. Cuttings were taken from 10 sites (20 × 25 cm each) for recording the phytomass stock of forest live cover on each sample area. Plants were cut off at the litter level, sorted by species, dried and weighed. Rating scales of digression were used to study the recreation influence. The degree of anthropogenic impact was determined by the content of toxic ingredients in plants of living ground cover. It is found that the toxic elements concentration in plants does not reach excessive values at which homeostasis disturbance happens. It was concluded that the changes in vegetation cover observed in 2017 in relation to the state of 2005 are more due to recreational than anthropogenic impact; which changed due to the introduction of a new technology at the JSC “RUSAL Krasnoyarsk Aluminum Plant”, which made it possible to reduce toxic industrialemissions. According to the study results, the species composition of the undergrowth and forest live cover was determined, the features of its change over a 12-year period were revealed. It is noted that species diversity has decreased and the proportion of synanthropic species has increased across all plots. Total forest live cover phytomass and individual species phytomass are determined at each plot. The regularities of change in different species contribution to the total stock of phytomass, depending on recreational impact changes, were identified. The ground cover recreational digression stages are determined by analyzing the changes in species diversity, the quantitative ratio of ecological-cenotic groups, the structure and the absolute value of phytomass. For citation: Goncharova I.A., Skripal’shchikova L.N., Barchenkov A.P., Shushpanov A.S. Understory Vegetation Cover Components Assessment in Anthropogenically DisturbedBirch Stands of Krasnoyarsk Forest-Steppe. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 1, pp. 75–87. DOI: 10.37482/0536-1036-2020-1-75-87 Funding: The study was carried out within the framework of the basic research projects of the Sukachev Institute of Forest SB RAS “Biodiversity of Indigenous Coniferous and Derivative Forest Ecosystems” (No. 0356-2016-0301) and “Dynamics of Siberian Forests in a Changing Climate. Monitoring of the Living State, Productivity and Ranges of the MainForest-Forming Species of Woody Plants” (No. 0356-2018-0739).

MODIS-Derived Estimation of Soil Respiration within Five Cold Temperate Coniferous Forest Sites in the Eastern Loess Plateau, China

Soil respiration (Rs) is seldom analyzed using remotely sensed data because satellite technology has difficulty monitoring various respiratory processes in the soil. We investigated the potential of remote sensing data products to estimate Rs, including land surface temperature (LST) and spectral vegetation indices from the Moderate Resolution Imaging Spectroradiometer (MODIS), using a nine-year (2007–2015) field measurement dataset of Rs and soil temperature (Ts) at five forest sites at the eastern Loess Plateau, China. The results indicate that soil temperature is the primary factor influencing the seasonal variation of Rs at the five sites. The accuracy of the model based on the observed data is not significantly different from the model based on MODIS-derived nighttime LST values. There was a significant difference with the model based on MODIS-derived daytime LST values. Therefore, nighttime LST was the optimum LST for estimation of Rs. The normalized difference vegetation index (NDVI) consistently exhibited a stronger correlation with Rs when compared to the green edge chlorophyll index and enhanced vegetation index. Further analysis showed that adding the NDVI into the model considering only Ts or nighttime LST could significantly improve the simulation accuracy of Rs. The models depending on nighttime LST and NDVI showed comparable accuracy with the models based on the in situ Ts and NDVI. These results suggest that models based entirely on remote sensing data from MODIS have the potential to estimate Rs at the cold temperate coniferous forest sites. The performance of the model in other vegetation types or regions has also been proved. Our conclusions further confirmed that it is feasible for large-scale estimates of Rs by means of MODIS data in temperate coniferous forest ecosystems.

Tree growth declines and mortality were associated with a parasitic plant during warm and dry climatic conditions in a temperate coniferous forest ecosystem.

Insects and pathogens are widely recognized as contributing to increased tree vulnerability to the projected future increasing frequency of hot and dry conditions, but the role of parasitic plants is poorly understood even though they are common throughout temperate coniferous forests in the western United States. We investigated the influence of western hemlock dwarf mistletoe (Arceuthobium tsugense) on large (≥45.7cm diameter) western hemlock (Tsuga heterophylla) growth and mortality in a 500year old coniferous forest at the Wind River Experimental Forest, Washington State, United States. We used five repeated measurements from a long-term tree record for 1,395 T. heterophylla individuals. Data were collected across a time gradient (1991-2014) capturing temperature increases and precipitation decreases. The dwarf mistletoe rating (DMR), a measure of infection intensity, varied among individuals. Our results indicated that warmer and drier conditions amplified dwarf mistletoe effects on T. heterophylla tree growth and mortality. We found that heavy infection (i.e., high DMR) resulted in reduced growth during all four measurement intervals, but during warm and dry intervals (a) growth declined across the entire population regardless of DMR level, and (b) both moderate and heavy infections resulted in greater growth declines compared to light infection levels. Mortality rates increased from cooler-wetter to warmer-drier measurement intervals, in part reflecting increasing mortality with decreasing tree growth. Mortality rates were positively related to DMR, but only during the warm and dry measurement intervals. These results imply that parasitic plants like dwarf mistletoe can amplify the impact of climatic stressors of trees, contributing to the vulnerability of forest landscapes to climate-induced productivity losses and mortality events.

Root–microbial interaction accelerates soil nitrogen depletion but not soil carbon after increasing litter inputs to a coniferous forest

Net primary productivity is expected to increase in many forests as Earth warms, which can increase litter inputs to soils and affect carbon (C) and nitrogen (N) dynamics. Understanding how increasing litter inputs affect soil C and N cycling in tropical and subtropical forests is important because they represent some of the most productive ecosystems on Earth, suggesting that small changes in these cycles can have large effects. To test the effects of increased litter inputs and the interactive effect between microbes and roots on soil C and N stocks and dynamics, we manipulated litter inputs and used trenching to exclude roots in a 40-year-old Cunninghamia lanceolata Lamb. (Chinese fir) plantation. At the site, we measured soil C and N pools, soil 13C and 15N natural abundance, and potential activities for C-, N-, and phosphorus-acquiring enzymes. After four years of experimental treatment, we found that increasing litter inputs reduced total soil N content by 26% relative to background litter inputs, but that increasing litter inputs did not affect soil C content in the plots with roots. In the plots without roots, both soil N and C did not change in response to litter inputs. In the plots with roots, soil δ15N increased with increasing litter inputs, but there was no effect in the plots without roots. We found a strong interactive effect between root and litter treatment on soil N pools and δ15N. The decline in soil N pools and increase in soil δ15N were associated with elevated potential enzyme activity for N-acquisition (N-acetyl glucosaminidase). Adding litter did not have a significant effect on soil C pools, likely because potential soil C losses were offset by increasing litter-derived C inputs. In contrast to C, adding litter decreased N availability, likely through multiple pathways including gaseous N losses, NO3− leaching, root N uptake, and interactions between saprotrophic microbes and roots during the four-year litter addition experiment. Global changes that increase litter production may lower N pools and imbalance C and N cycling in subtropical coniferous forest ecosystems.

Soil net methane uptake rates in response to short-term litter input change in a coniferous forest ecosystem of central China

The uptake of CH4 by well-drained soil plays a vital role in mitigating the atmospheric CH4, but the impacts of shift in plant litter input on uptake of CH4 and the underlying mechanism are not fully understood. Here, we conducted in situ measurements of soil CH4 flux rates monthly throughout the year after the short-term litter input manipulations (i.e. Detritus Input and Removal Treatment-DIRT: control, CK; double litter, DL; no litter, NL; no roots, NR; and no aboveground litter and no roots, NRNL) in a coniferous forest (Platycladus orientalis (Linn.) Franco) ecosystem in subtropical China. The associated microclimates, soil properties and microbial PLFAs were also measured. Our results showed that soils acted as CH4 sink in all litter manipulation treatments, and the CH4 sink capacity significantly differed under litter manipulation treatments. Based on annual average values, net CH4 uptake rates decreased by 37.7 ± 4.9% and 41.7 ± 5.8% in the NL and NRNL treatments (i.e. litter layer removal), respectively, compared to the CK treatment. Thus, the net CH4 uptake induced by litter layer approximately accounted for 37.7 ± 4.9% of the total net CH4 uptake rate. The net CH4 uptake rate was not significantly influenced by the root exclusion (NR) treatment. In contrast, the effect of litter addition on net CH4 uptake rate was strongly depended on soil water content. During the dry season, litter addition did not significantly affect net CH4 uptake rate. In contrast, during the wet season, the net CH4 uptake rate decreased by 47.1 ± 4.9% in the DL treatment compared to the CK treatment. There was no significant difference in net CH4 uptake rate between dry and wet season under other litter input manipulation treatments. The net CH4 uptake rate was positively correlated with the abundance of methanotrophic bacteria across all litter input manipulation treatments, whereas the significant negative relationship between net CH4 uptake rate and water filled pore space (WFPS) was only found in the DL treatment. Overall, our results suggest that aboveground organic layer (i.e. litter) is more important in regulating the soils acting as atmospheric CH4 sink than roots, while the regulating function primarily depends on soil dry/wet conditions and the abundance of methanotrophic bacteria.

Effects of Experimental Warming and CO2 Concentration Doubling on 13C CPMAS NMR Spectra of Humin in Coniferous Forest Ecosystems of the Eastern Tibetan Plateau in China

Effects of Experimental Warming and CO2 Concentration Doubling on 13C CPMAS NMR Spectra of Humin in Coniferous Forest Ecosystems of the Eastern Tibetan Plateau in China

Growing season water balance of an inner alpine Scots pine (Pinus sylvestris L.) forest.

We estimated components of the water cycle of a 150-year-old Pinus sylvestris forest in an inner Alpine dry valley of the Tyrol, Austria throughout five growing seasons. Forest canopy transpiration (TC) was measured by sap flow measurements scaled to the stand canopy level. Estimates of understory transpiration and forest floor evaporation (ETU) were derived from the soil water budget method, while interception (I) was modelled. Growing season cumulative evapotranspiration (ET = TC + ETU + I) varied between 256 and 322 mm or 51 to 79% of the growing season precipitation. The contribution of TC, ETU, and I to ET were 33, 40 and 27% respectively. Although these values of each layer (evapo)-transpiration are in good agreement with studies carried out in other European Scots pine forests, our estimated growing season total forest water use (Ttot = Tc + ETu) of 200-244 mm is at the lower end of values reported for coniferous forest ecosystems, and thus reflects an adaptation to the low shallow soil water availability. We conclude that Scots pine forests in inner alpine dry valleys are able to cope with high evaporative demand, even when shallow soil water availability is limited.

Shifts in soil organic carbon dynamics under detritus input manipulations in a coniferous forest ecosystem in subtropical China

The underlying mechanism of how shifts in plant detritus input impact soil organic carbon (SOC) dynamics is not fully understood. Here we investigated the soil C content in different fractions (aggregates, labile and recalcitrant pool) after two years of detritus input manipulations (i.e. detritus input and removal treatment–DIRT: control, CK; double litter, DL; no litter, NL; no roots, NR; no aboveground litter and no roots, NRNL) in a coniferous forest (Platycladus orientalis (Linn.) Franco) ecosystem in subtropical China. The root exclusion treatments (NR and NRNL) significantly decreased the macro-aggregate (>2000 μm) fraction by 23.4%–27.7% compared to CK after two-year detritus input manipulation, and accordingly decreased the C content in macroaggregates. In contrast, the aboveground litter removal and addition (DL and NL) did not significantly impact those properties. Labile SOC significantly declined in the detritus removal treatments, while recalcitrant SOC remained relatively stable. In addition, root exclusion significantly reduced total microbial biomass and most of the taxonomic biomarkers compared to the CK. Fungal biomass were positively correlated with the proportion of macroaggregates across treatments. Principal component analysis revealed the separation of root exclusion treatments from the other detritus input manipulations was based on lower soil C content and proportion of macroaggregates. Overall, our results suggest that future shifts in plant detritus input, especially decreases in belowground litter inputs, can strongly and rapidly reduce SOC pools by reducing the proportion of macroaggregates and the C content in macroaggregates, highlighting the importance of root in regulating soil C sequestration in response to future climatic scenarios.

Experimental addition of nitrogen to a whole forest ecosystem at Gårdsjön, Sweden (NITREX): Nitrate leaching during 26 years of treatment

Chronic high deposition of nitrogen (N) to forest ecosystems can lead to increased leaching of inorganic N to surface waters, enhancing acidification and eutrophication. For 26 years nitrogen has been added as ammonium nitrate (NH4NO3) at 40 kg N ha−1 yr−1 to a whole forested catchment ecosystem at Gårdsjön, Sweden, to experimentally simulate the transition from a N-limited to N-rich state. Over the first 10 years of treatment there was an increasing amount of nitrate (NO3−) and to a lesser extent ammonium (NH4+) lost in runoff, but then N leaching stabilised, and for the subsequent 16 years the fraction of N added lost in runoff remained at 9%. NO3− concentrations in runoff were low in the summer during the first years of treatment, but now are high throughout the year. High frequency sampling showed that peaks in NO3− concentrations generally occurred with high discharge, and were enhanced if high discharge coincided with occasions of N addition. Approximately 50% of the added N has gone to the soil. The added N is equivalent to 140 years of ambient N deposition. At current ambient levels of N deposition there thus appears to be no immediate risk of N saturation at this coniferous forest ecosystem, and by inference to other such N-limited forests in Scandinavia.

Response diversity, functional redundancy, and post-logging productivity in northern temperate and boreal forests.

The development of efficient ecosystem resilience indicators was identified as one of the key research priorities in the improvement of existing sustainable forest management frameworks. Two indicators of tree diversity associated with ecosystem functioning have recently received particular attention in the literature: functional redundancy (FR) and response diversity (RD). We examined how these indicators could be used to predict post-logging productivity in forests of Québec, Canada. We analysed the relationships between pre-logging FR and RD, as measured with sample plots, and post-logging productivity, measured as seasonal variation in enhanced vegetation index obtained from MODIS satellite imagery. The effects of the deciduous and coniferous tree components in our pre-disturbance diversity assessments were isolated in order to examine the hypothesis that they have different impacts on post-disturbance productivity. We also examined the role of tree species richness and species identity effects. Our analysis revealed the complementary nature of traditional biodiversity indicators and trait-based approaches in the study of biodiversity-ecosystem-functioning relationships in dynamic ecosystems. We report a significant and positive relationship between pre-disturbance deciduous RD and post-disturbance productivity, as well as an unexpected significant negative effect of coniferous RD on productivity. This negative relationship with post-logging productivity likely results from slower coniferous regeneration speeds and from the relatively short temporal scale examined. Negative black-spruce-mediated identity effects were likely associated with increased stand vulnerability to paludification and invasion by ericaceous shrubs that slow down forest regeneration. Response diversity outperformed functional redundancy as a measure of post-disturbance productivity most likely due to the stand-replacing nature of the disturbance considered. To the best of our knowledge, this is among the first studies to report a negative significant relationship between a component of RD and ecosystem functioning, namely coniferous RD and forest ecosystem productivity after a stand-replacing disturbance.

Throughfall, stemflow, and interception characteristics of coniferous forest ecosystems in the western black sea region of Turkey (Daday example).

This study aims to identify precipitation, throughfall, stemflow, precipitation, and interception processes in pure black pine, pure Scots pine, and mixed black pine-Scots pine forest ecosystems and present the precipitation partitioning according to different stand types. Throughfall and stemflow measurements were performed using five standard precipitation gauges in a pilot area established to represent pure black pine, pure Scots pine, and mixed black pine-Scots pine stands in the Bezirgan Basin. The total precipitation was measured in an open field close to the study area. Throughfall values were calculated as the percentage of precipitation measured in an open field. According to the results of the study, the throughfall values were 69.8% in black pine, 73.9% in Scots pine, and 77.7% in the mixed black pine-Scots pine stands; the stemflow values were 2.6% in black pine, 5.9% in Scots pine, and 3.1% in the mixed black pine-Scots pine stands; the amounts of precipitation reaching the forest floor were 72.3% in black pine, 79.8% in Scots pine, and 80.7% in the mixed black pine-Scots pine stands; and the interception values were found to be 27.7% in black pine, 20.2% in Scots pine, and 19.2% in the mixed black pine-Scots pine stands.

Distribution patterns of tree, understorey, and detritus biomass in coniferous and broad-leaved forests of Western Himalaya, India

ABSTRACTForest biomass pools are the major reservoirs of atmospheric carbon in both coniferous and broad-leaved forest ecosystems and thus play an important role in regulating the regional and global carbon cycle. In this study, we measured the biomass of trees, understorey, and detritus in temperate (coniferous and broad-leaved) forests of Kashmir Himalaya. Total ecosystem dry biomass averaged 234.2 t/ha (ranging from 99.5 to 305.2 t/ha) across all the forest stands, of which 223 t/ha (91.9–283.2 t/ha) were stored in above- and below-ground biomass of trees, 1.3 t/ha (0.18–3.3 t/ha) in understorey vegetation (shrubs and herbaceous), and 9.9 t/ha (4.8–20.9 t/ha) in detritus (including standing and fallen dead trees, and forest floor litter). Among all the forests, the highest tree, understorey, and detritus biomass were observed in mid-altitude Abies pindrow and Pinus wallichiana coniferous forests, whereas the lowest were observed in high-altitude Betula utilis broad-leaved forests. Basal area has showed significant positive relationship with biomass (R2 = 0.84–0.97, P < 0.001) and density (R2 = 0.49–0.87). The present study will improve our understanding of distribution of biomass (trees, understorey, and detritus) in coniferous and broad-leaved forests and can be used in forest management activities to enhance C sequestration.

酸性沈着の影響下にある広葉樹林, 針葉樹林生態系における硫黄の分布と循環II : 沈着・排出および系内の循環

酸性沈着の影響下にある広葉樹林, 針葉樹林生態系における硫黄の分布と循環II : 沈着・排出および系内の循環

酸性沈着の影響下にある広葉樹林, 針葉樹林生態系における硫黄の分布と循環I : 乾物現存量と硫黄の分布

酸性沈着の影響下にある広葉樹林, 針葉樹林生態系における硫黄の分布と循環I : 乾物現存量と硫黄の分布