Forest Humus Research Articles

"Ectomycorrhizal exploration type" could be a functional trait explaining the spatial distribution of tree symbiotic fungi as a function of forest humus forms.

In European forests, most tree species form symbioses with ectomycorrhizal (EM) and arbuscular mycorrhizal (AM) fungi. The EM fungi are classified into different morphological types based on the development and structure of their extraradical mycelium. These structures could be root extensions that help trees to acquire nutrients. However, the relationship between these morphological traits and functions involved in soil nutrient foraging is still under debate.We described the composition of mycorrhizal fungal communities under 23 tree species in a wide range of climates and humus forms in Europe and investigated the exploratory types of EM fungi. We assessed the response of this tree extended phenotype to humus forms, as an indicator of the functioning and quality of forest soils. We found a significant relationship between the relative proportion of the two broad categories of EM exploration types (short- or long-distance) and the humus form, showing a greater proportion of long-distance types in the least dynamic soils. As past land-use and host tree species are significant factors structuring fungal communities, we showed this relationship was modulated by host trait (gymnosperms versus angiosperms), soil depth and past land use (farmland or forest).We propose that this potential functional trait of EM fungi be used in future studies to improve predictive models of forest soil functioning and tree adaptation to environmental nutrient conditions.

The Combustion of Forest Humus Blended with Low-Rank Coal: Effects of Oxygen Ratio and Blending Ratio

In this study, the combustion characteristics of pine needles, pine needle humus, and the co-combustion of these two types of biomass with coal were compared. In addition, the optimization of the combustion performance of coal/humus was assisted through the following studies: (i) the combustion performance of coal/pine needle humus was studied under four different oxygen concentrations (N2, 10%O2/90%N2, 20%O2/80%N2, and 40%O2/60%N2); (ii) the synergistic effect between the humus and coal during combustion was also investigated by adjusting the blending ratio and oxygen content; (iii) the mechanisms of the optimized combustion processes were expounded by kinetics and thermodynamics discussion. The results demonstrated that the combustion characteristics of the coal/humus blends were found to be higher than those of the coal/pine needle blends. The coupling interactions of the oxygen content and blending ratio contributed to the significant synergistic effect between the two fuels, and the synergistic effect showed a nonlinear variation with an increased oxygen concentration. The synergistic effect in a rich oxygen environment (O240%/N260%) is 5.1 times greater than that in the synthetic air (O220%/N280%) and 13.8 times greater than that in the oxygen-poor environment (O210%/N290%). Hence, the blending ratio could be adjusted to maintain the intensity of the synergistic effect in an oxygen-rich atmosphere.

Cherrapunjee: An Example of Human Impact on Environment

Palynological studies in Cherrapunjee located in Meghalaya, India have concluded that the modern grasslands of Cherrapunjee are the result of anthropogenic activity in the recent past leading to the deterioration of the primary dense forest. The forest humus was removed after extensive deforestation by human activity. Human presence in the area is indicated by Oryza Sativa, the common domesticated rice variety and Plantago lanceolata, which is a common weed of cultivated land. Like many other regions of the world, this human activity is thought to be agriculture, mainly shifting cultivation. But shifting cultivation is also practised in Garo Hills, Nagaland, and Arunachal Pradesh where pollen profiles of the recent past do not indicate the complete disappearance of the primary dense forest. In fact, indigenous shifting cultivators across Northeast India never uproot the large trees because the root foliage holds the soil. Within six months after the plot is abandoned, the primary forest bounces back to its original form. This study hypothesises that human activity other than agriculture was responsible for the deterioration of the primary dense forest of Cherrapunjee. The study is based on the assumption that the whole process of erecting megaliths and iron smelting technology in the area resulted in the complete destruction of the primary forest on the flat top surface of the plateau where Cherrapunjee is located.

Iodine distribution and volatilization in contrasting forms of forest humus during a laboratory incubation experiment

Radionuclides 129I (t1/2 = 15.7 × 106 years) and 131I (t1/2 = 8.02 days) are both introduced into the environment as a result of nuclear human activities. Environmental transfer pathways and fluxes between and within ecosystems are essential information for risk assessment. In forest ecosystems, humus degradation over time could result in re-mobilization and then downward migration and/or volatilization of intercepted 129I. In order to estimate the scale of these processes, humus (mull and moder forms) sampled under deciduous and coniferous forests were spiked with 125I− (t1/2 = 59.4 days), as a surrogate for 129I, in order to study the evolution of its water-soluble and organic fractions as well as the volatilization rate during humus degradation at laboratory scale. To our knowledge, this is the first time that interactions between iodine and contrasting forms of forest humus have been investigated. The evolution of native stable iodine (127I) pools in unspiked humus was also studied.The nature of the humus’ organic matter appears to be a factor that impacts on the proportions of water-soluble and organic fractions of iodine and on their evolution. Iodine-125 was mainly organically bound (fraction for mulls and moders: ∼54–59 and 41–49%, respectively) and no clear evolution was observed within the 4-month incubation period. A large decrease in 125I water-solubility occurred, being more marked for mull (from ∼14–32 to 3–7%) than for moder (from ∼21–37 to 7–19%) humus. By contrast, a significant fraction was not extractible (∼38–43%) and varied in inverse proportion to the water-soluble fraction, suggesting a stabilization of iodine in humus after wet deposit. The nature of the humus organic matter also impacted on 125I volatilization. Although of the same order of magnitude, the total volatilization of 125I was higher for moders (∼0.039–0.323%) than for mulls (∼0.015–0.023%) within the 4-month incubation period. Volatilization rates for mulls were correlated with the water-soluble fraction, implying that volatilization of 125I could occur from the humus solution. Our results showed that humus is thus a zone of iodine accumulation by association with organic matter and that potential losses by lixiviation are significantly more important compared to volatilization.

After the Storm: Fate and Leaching of Particulate Nitrogen (PN) in the Fluvial Network and the Influence of Watershed Sources and Moisture Conditions

Large storms can erode, transport, and deposit substantial amounts of particulate nitrogen (PN) in the fluvial network. The fate of this input and its consequence for water quality is poorly understood. This study investigated the transformation and leaching of PN using a 56-day incubation experiment with five PN sources: forest floor humus, upland mineral A horizon, stream bank, storm deposits, and stream bed. Experiments were subjected to two moisture regimes: continuously moist and dry–wet cycles. Sediment and porewater samples were collected through the incubation and analyzed for N and C species, as well as the quantification of nitrifying and denitrifying genes (amoA, nirS, nirK). C- and N-rich watershed sources experienced decomposition, mineralization, and nitrification and released large amounts of dissolved N, but the amount of N released varied depending on the PN source and moisture regime. Drying and rewetting stimulated nitrification and suppressed denitrification in most PN sources. Storm deposits released large amounts of porewater N regardless of the moisture conditions, indicating that they could readily act as N sources under a variety of conditions. The inputs, processing, and leaching of large, storm-driven PN inputs become increasingly important as the frequency and intensity of large storms is predicted to increase with global climate change.

Chlorination of soil organic matter: The role of humus type and land use

The levels of natural organic chlorine (Clorg) typically exceed levels of chloride in most soils and is therefore clearly of high importance for continental chlorine cycling. The high spatial variability raises questions on soil organic matter (SOM) chlorination rates among topsoils with different types of organic matter. We measured Clorg formation rates along depth profiles in six French temperate soils with similar Cl deposition using 36Cl tracer experiments. Three forest sites with different humus types and soils from grassland and arable land were studied. The highest specific chlorination rates (fraction of chlorine pool transformed to Clorg per time unit) among the forest soils were found in the humus layers. Comparing the forest sites, specific chlorination was highest in mull-type humus, characterized by high microbial activity and fast degradation of the organic matter. Considering non-humus soil layers, grassland and forest soils had similar specific chlorination rates in the uppermost layer (0–10 cm below humus layer). Below this depth the specific chlorination rate decreased slightly in forests, and drastically in the grassland soil. The agricultural soil exhibited the lowest specific chlorination rates, similar along the depth profile. Across all sites, specific chlorination rates were correlated with soil moisture and in combination with the patterns on organic matter types, the results suggest an extensive Cl cycling where humus types and soil moisture provided best conditions for microbial activity. Clorg accumulation and theoretical residence times were not clearly linked to chlorination rates. This indicates intensive Cl cycling between organic and inorganic forms in forest humus layers, regulated by humic matter reactivity and soil moisture, while long-term Clorg accumulation seems more linked with overall deep soil organic carbon stabilization. Thus, humus types and factors affecting soil carbon storage, including vegetation land use, could be used as indicators of potential Clorg formation and accumulation in soils.

Stump removal and tree species composition promote a bacterial microbiome that may be beneficial in the suppression of root disease.

Stumping is an effective forest management practice for reducing the incidence of Armillaria root-rot in regenerating trees, but its impact on the soil bacterial community has not been ascertained. This study investigated the long-term impact of stumping and tree species composition in a 48-year-old trial at Skimikin, British Columbia, on the relative abundance, diversity and taxonomic composition of bacterial communities by sequencing the v4 region of 16S rRNA gene using the Illumina Miseq platform. A total of 108 samples were collected from the forest floor (fermented (F) and humus (H) layers) and mineral soil (A (0-10cm) and B (10-20cm) horizons) of 36 plots (half each stumped or unstumped) that were planted with pure stands and admixtures of Douglas-fir, western redcedar and paper birch. Bacterial α-diversity in the B horizon declined with stumping whereas β-diversity was affected both by tree species and stumping treatments, with fir and birch supporting distinct bacterial communities. All horizons of stumped plots of birch and its admixtures were significantly enriched with potential plant growth-promoting bacteria. In conclusion, stumping along with planting birch alone or in admixture with other species promotes a bacterial microbiome that appears beneficial in the suppression of root disease.

Superação de dormência de sementes e desenvolvimento de mudas de jatobazeiro em substratos alternativos

The propagation of the jatoba (Hymenaea courbarilL.) by seeds is highly promising in the recovery of degraded areas. Thus, the present research aimed to compare methods forjatoba plant seeds dormancy overcomingand to evaluate the development of seedlings of this species in alternative substrates. In the first experiment, in screened nursery, a completely randomized design was used, with four replications and seven seed treatments: scarification with sandpaper(SS), SS and immersion in water for 24 h, SS and immersion in water for 48 h, intact seed, seed immersed in water for 48 h and seed immersed in water for 96 h. The seedlings that emergency were counted every other days, from 13 to 51days after sowing, quantifying the emergence percentage, the emergence speed index and the emergence average time.The second experiment, in greenhouse,was composed ofthree replicates, in randomized blocks, being seven substrates were used:commercial substrate (CS); 40% SC + 60% forest humus (FH); 40% SC + 60% charcoal rice husk (CRH); 40% SC + 60% bovine manure (BM); 40% CRH + 60% BM; 40% CRH + 60% FH; e 40% FH + 60% BM. At 50, 70 and 120 days after sowing were evaluated the parameters: seedlingheight, leafsnumber, stem diameter, fresh matterand dry matter of aerial partand roots, and leaf area.At 120 DAS, the chlorophyll index was also evaluated. The scarification with sandpaper and immersion of seeds in water for 24 hours presented a greater emergence (96.4% and IVE = 0.697).The mixture containing 40% FHand 60% BMresulted seedlings with a larger leaf area, chlorophyll index and roots and aerial part dry matter, at 120 days after sowing.

Forest Humus Type Governs Heavy Metal Accumulation in Specific Organic Matter Fractions

Soils have the potential to accumulate heavy metals and the capacity to do so is strongly related the properties of each soil. Soil organic matter is a key factor in the retention, release, and bioavailability of heavy metals, and here we have determined the accumulation of heavy metals in various types of humus in the Rybnik Forest District in southern Poland. In a novel approach, we analyzed relationships between heavy metals within soil organic matter fractions and evaluated the role of organic fractions in mediating metal mobility. Specifically, we tested whether (i) the type of forest humus determines the heavy metal accumulation; (ii) heavy metals accumulation is associated with soil organic matter fractions; and (iii) heavy metals have an inhibitory influence on biochemical properties especially enzymes activity in different humus types. Four types of humus were sampled (mor, moder, moder-mull, mull), physically fractioned, and a number of chemical and biochemical properties were analyzed. Calculated geo-accumulation index (Igeo) and enrichment factor (EF) confirmed soil pollution with Cd and Pb. The type of humus differed in the accumulation of heavy metals, which is associated to the variable concentration of organic matter remaining at each decay class. We found no relationship between enzymatic activity and heavy metals concentration except for a positive correlation between urease activity and nickel concentration. Considering wider evidence, we propose a biogeochemical link between nickel deposition and the production of soil-borne urease in these forest soils.

Topsoil acidity of forested mineral lands in Estonia

Abstract. The active acidity (pH) of forested mineral lands’ topsoil, its relationships with alternative soil acidity characteristics and the influence of soil acidity on forest soils’ profile fabric and functioning are analysed in the pedo-ecological conditions of northeastern Europe. The active acidity of the forest floor (O-horizon) was taken as the baseline for this analysis. The acidity of the forest floor was studied in accordance with the underlying soil horizons, which are humus and/or raw-humus horizons in the more fertile soils, whereas in less fertile soils, they are podzolized horizons. The data on soil acidity are presented by main soil types, forest site types, forest humus cover types (pro humus forms) and forest stand groups. In this work, the influences of forest floor acidity on mineral topsoil fabric, soil processes and peculiarities of carbon sequestration are explained. The active acidity of the forest floor provides a great indicative value in elucidating the regularities of the forest soil cover, as a whole, formation and functioning. For evaluating the normality of soil functioning, or the absence of disturbances in ecosystem functioning, the intervals of soil type specific reference pH levels have been established.

Gas Diffusivity in the Forest Humus Layer

While several diffusivity models have been developed for mineral soils, there are few data for the forest humus layers that overlie, and are distinct from, the mineral soil. We measured soil gas diffusivity of the organic layer of spruce and beech stands. Total pore space and relative soil gas diffusivity were much higher in the humus layer than in mineral soil. An exponential diffusivity function was used to describe relative soil gas diffusivity in the humus layer of all spruce sites using one parameter set. The best-fit parameters exceeded the range recommended for mineral soil, indicating the distinctness in pore structure of mineral soil and the organic layer. Different model parameter sets were required to describe the different types of humus at the beech sites. As a consequence, traditional predictive models developed for mineral soil should not be used to derive diffusivity values to interpret the aeration status of the forest humus layer. Specific parameter sets should be used for calculating soil gas fluxes through these layers using the gradient flux approach.

Spatiotemporal evolution of paludification associated with autogenic and allogenic factors in the black spruce–moss boreal forest of Québec, Canada

AbstractPaludification is the most common process of peatland formation in boreal regions. In this study, we investigated the autogenic (e.g., topography) and allogenic (fire and climate) factors triggering paludification in different geomorphological contexts (glaciolacustrine silty-clayey and fluvioglacial deposits) within the Québec black spruce (Picea mariana)–moss boreal forest. Paleoecological analyses were conducted along three toposequences varying from a forest on mineral soil to forested and semi-open peatlands. Plant macrofossil and charcoal analyses were performed on basal peat sections (≤50 cm) and thick forest humus (<40 cm) to reconstruct local vegetation dynamics and fire history involved in the paludification process. Results show that primary paludification started in small topographic depressions after land emergence ca. 8000 cal yr BP within rich fens. Lateral peatland expansion and secondary paludification into adjacent forests occurred between ca. 5100 and 2300 cal yr BP and resulted from low-severity fires during a climatic deterioration. Fires that reduced or eliminated entirely the organic layer promoted the establishment ofSphagnumin microdepressions. Paludification resulted in the decline of some coniferous species such asAbies balsameaandPinus banksiana. The paleoecological approach along toposequences allowed us to understand the spatiotemporal dynamics of paludification and its impacts on the vegetation dynamics over the Holocene.

Blended pulp mill, forest humus and mine residual material Technosols for mine reclamation: A growth-chamber study to explore the role of physiochemical properties of substrates and microbial inoculation on plant growth

A growth chamber trial was conducted to investigate the effects of blends of pulp and paper mill residuals and forest humus on soil properties, microbial communities and germination rate and biomass production of annual ryegrass (Lolium multiflorum) in both acid-producing and neutral to mildly alkaline mine tailings in a mine reclamation context. The organic residual amendments improved the nutritional status of the tailings substrates, and increased pH in acid-generating tailings, leading to higher germination rates and improved plant growth. A trace addition (<0.02% of sludge by dry weight) of natural forest floor material as a microbial inoculum to the sludge could increase plant biomass up to four-fold. The effects of sludge application on bioavailability of metals were variable, with the concentration of soluble copper (Cu) and nickel (Ni) increasing in some of the substrates following organic amendments. Addition of paper mill residuals to mine tailings modified the microbial communities observed in the oligotrophic tailings with the majority of DNA sequences in the sludge amended substrates being found to be closely related to heterotrophic bacterial species rather than the chemolithotrophic communities that dominate tailings environments.

The response of Šampion trees growing on different rootstocks to applied organic mulches and mycorrhizal substrate in the orchard

Abstract The aim of the study was to evaluate the effects of using organic mulches: barley straw, chipped pine bark, forest humus, compost, cow manure, commercial peat moss, and commercial mycorrhizal substrate on the growth and yield of Sampion apple trees produced on M26, P2, M9, and P22 rootstocks. The investigations were conducted using Sampion apple trees grown on chosen rootstocks and substrates: barley straw, chipped pine bark, forest humus, compost, cow manure, commercial peat moss substrate, and commercial mycorrhizal substrate. Apple trees grown on all analysed rootstocks reached the greatest height on compost and cow manure mulches, and the biggest trunk diameter was achieved by trees growing on the straw mulch. The greatest number (P

Vegetation and climate history of Quebec’s mixed boreal forest suggests greater abundance of temperate species during the early- and mid-Holocene

Today, scattered disjunct stands of two temperate species, yellow birch and white pine, are present north of their continuous distributional range in southern Quebec (Canada) at topographical locations that offer protection from severe fires. This study tested whether these species had populations more numerous and widespread millennia ago when the climate was presumably warmer. Specifically, this research involved the analyses of pollen, plant macrofossils, and charcoal fragments of two sites within the western part of Quebec’s balsam fir – paper birch bioclimatic domain: a forest humus deposit from a yellow birch stand (local scale), and a peatland (regional scale). Fossil data suggest that white pine was more abundant regionally between 7500 and 5000 cal. BP, before coming rare under subsequent cooler conditions. Likewise, yellow birch was more abundant regionally between 7700 and 1500 cal BP. Its subsequent decline and the local disappearance of white pine by ∼200 cal. BP may both be explained by the severe fires that occurred in recent centuries, as well as the rarity of suitable habitats for these species. The sustained presence of temperate species in mixed boreal forests is the result of the combined action of climate, natural disturbances and habitat characteristics.

Polycyclic Aromatic Hydrocarbons Content in Contaminated Forest Soils with Different Humus Types

The aim of the study was to determine polycyclic aromatic hydrocarbon (PAH) content in different forest humus types. The investigation was carried out in Chrzanów Forest District in southern Poland. Twenty research plots with different humus types (mor and mull) were selected. The samples for analysis were taken after litter horizons removing from a depth of 0–10 cm (from the Of- and Oh-horizon total or A-horizon). pH, organic carbon and total nitrogen content, base cations, acidity, and heavy metal content were determined. In the natural moisture state, the activity of dehydrogenase was determined. The study included the determination of PAH content. The conducted research confirms strong contamination of study soil by PAHs and heavy metals. Our experiment provided evidence that different forest humus types accumulate different PAH amounts. The highest content of PAHs and heavy metals was recorded in mor humus type. The content of PAHs in forest humus horizon depends on the content and quality of soil organic matter. Weaker degradation of hydrocarbons is associated with lower biological activity of soils. The mull humus type showed lower content of PAHs and at the same time the highest biological activity confirmed by high dehydrogenase activity.

Signatures of chlorinated dioxins and furans along the exposure path – The relation between vegetation and soil

Polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) belong to the most toxic persistent organic environmental pollutants. Therefore, knowledge about their fate along the exposure path is of special concern. In order to comprehend the transfer of PCDD/Fs across different environmental compartments, PCDD/F concentrations in plants and in soil were evaluated. Pairs of soil and plant samples were selected according to the shortest distance between sampling points. At 15 sites PCDD/F concentrations in spruce needles and in forest humus layers where compared. Summer conditions were evaluated on the basis of 8 sites with ryegrass- and grassland topsoil samples. Autumn conditions were addressed using 7 sites with curly kale and topsoil samples under grassland. Correlation analyses of the PCDD/F congener profiles for plant- and soil samples were conducted. The correlations were compared to influencing site (e.g. local temperature) and spatial as well as temporal offset parameters. No governing parameter that decisively influenced the similarity between plant and soil signature became evident. By means of the toxicity factors of TEQ-WHO, tetra- and penta-PCDD/F homologues were assigned to the group of low-chlorinated homologues (lcH), and hexa-, hepta- and octa-PCDD/F homologues to the high-chlorinated homologues (hcH). lcH and hcH are presumed to differ in solubility, volatility and rate of degradation. The ratio of lcH/hcH revealed characteristic fingerprints that enabled the differentiation of the individual PCDD/F-plant and -soil pairs. Spruce-humus pairs showed a close relation during winter exposure times, while the lower summer concentrations were not reflected in the humus layer. Kale was exposed at the beginning of the season with elevated PCDD/F immissions, and showed a closer relation to grassland topsoil than did ryegrass. lcH/hcH proved as a simple criterion that can reveal related PCDD/F fingerprints of different environmental compartments despite signal attenuation due to decomposition, volatilization and particulate transport.

Pedogenesis: Humus forms and soils under spruce forest by a morphological approach

Our investigation pointed out, with a detailed classification, a vast variability of forest humus and soil under spruce forests on two different sites with North and South exposition, permitting to identify a pedogenetic trend between different sylvogenetic phases of forest evolution and specific humus forms.We identified the soil indicators that have to be checked for measuring soil changes relating to humus changing. First of all we noted a humus change on soil morphological features. Such features are produced by physical and biochemical pedofauna bioturbations. Pedofauna according to the peculiar microclimate of the soil, depends on the forest development. Biochemical litter environment produces specific humus form.During the growth of a forest there is a policyclic soil evolution with physical-chemical changes that we can observe in time on soil and humus forms. The humus forms are related with the air (biospheric fluxes), with the organic-mineral components (as micro and macroelements cycles) and with pedofauna. We observe physical change (as structure, porosity, horizontation, particle-size, pattern, mineralogy) and chemical change (as for pH, C, N) in soil horizons which is due to humus change.The humus forms have been investigated in relation to the development of vegetation growth, with the aim to identify a representative humus form of a specific sylvogenetic phase. Such research suggests an hypothesis that the humus form is a guide of the environment states to which it belongs. During the open canopy stage (that is the phase before the presence of very young plantations) it is possible to observe many different humus forms: from the acid one as Moder (Hemimoder), that is heredity of the previous use of the land, to the new form of Mull (Oligomull) that is the result of the new forest cycle, more suitable for spruce renovation.

Ectomycorrhizal fungi increase the vitality of Norway spruce seedlings under the pressure of Heterobasidion root rot in vitro but may increase susceptibility to foliar necrotrophs

We tested if root colonisation by ectomycorrhizal fungi (EMF) could alter the susceptibility of Norway spruce (Picea abies) seedlings to root rot infection or necrotic foliar pathogens. Firstly, spruce seedlings were inoculated by various EMF and challenged with Heterobasidion isolates in triaxenix tubes. The ascomycete EMF Meliniomyces bicolor, that had showed strong antagonistic properties towards root rot causing Heterobasidion in vitro, protected spruce seedlings effectively against root rot. Secondly, spruce seedlings, inoculated with M. bicolor or the forest humus, were subjected to necrotrophic foliar pathogens in conventional forest nursery conditions on peat substrates. Botrytis cinerea infection after winter was mild and the level of needle damage was independent of substrate and EMF colonisation. Needle damage severity caused by Gremminiella abietina was high in seedlings grown in substrates with high nutrient availability as well as in seedlings with well-established EMF communities. These results show that albeit M. bicolor is able to protect spruce seedlings against Heterobasidion root rot in axenic cultures it fails to induce systemic protection against foliar pathogens. We also point out that unsterile inoculum sources, such as the forest humus, should not be considered for use in greenhouse conditions as they might predispose seedlings to unintended needle damages.

Forest humus forms as a playground for studying aboveground-belowground relationships: Part 2, a case study along the dynamics of a broadleaved plain forest ecosystem

A set of research studies has been performed over a period of 10 years on the silvicultural cycle of an even-aged beech forest in Normandy, France. The striking results about both soil functioning (litter decomposition, N cycling, soil C stock) and soil biota (microorganisms, mesofauna, and macrofauna) are presented with the goal of developing an empirical model of the successional patterns of aboveground-belowground relationships in forests. Our purpose was to test the hypothesis stating that the best performance of this forest ecosystem, as high organic matter recycling and low biogenic element losses, is achieved in an ecological stage exhibiting limiting similarity in functional traits and maximizing traits complementary for both plant and soil communities. The present synthesis showed that this hypothesis seems to be confirmed for a late successional stage, i.e., a mature even-aged forest with a closed canopy. The most organized communities, on the basis of ecological requirement similarity, were found in 130 year-old stands. These stands also support the greatest values in microbial functional diversity, in soil C stock and in nitrogen mineralization. Nitrogen losses were the lowest in 95 year-old stands. We also provide some methodological advices for using humus forms for the study of aboveground-belowground relationships in forest ecosystems.