Influence of tree species on acidification and mineral pools in deciduous forest soils of South Sweden

The influence of tree species on chemical properties of the soil profile (0 to 70 cm), especially acidity and cation pools, was studied below canopies of 100 to 150 yr old individuals of Fagus sylvatica L., Quercus robur L., Carpinus betulus L., Tilia cordata Mill, and Acer platanoides L., in three mixed deciduous forests. The pH(H₂O) range in the topsoil (0 to 5 cm) was 4.2 to 5.3 at the different sites and increased for all species by about 0.2 pH units to the upper C-horizon (50 to 70 cm). Carpinus had higher pH and base saturation, and the total exchangeable store of Ca (0 to 70 cm) at the ‘poorest’ site was ca 1.5 times greater than for Fagus and Quercus. Soils were less acid under crowns of Quercus than under Fagus and Carpinus in the upper 20 cm of the soil profile in the ‘richest’ site, but more acid at the deeper levels. The total exchangeable pools (0 to 70 cm) of K and Zn were 2 and 1.6 times greater under Quercus at the ‘richest’ site. Tilia had 10 to 20% units higher base saturation values and twice as much exchangeable Ca and Mg than the other species. It was concluded that out of all tree species studied, Tilia acidified the soil the least. The current annual total proton load (TPL) on the soil was 1.3 to 3.0 kEq ha^?1 yr^?1. The annual acid load due to cation excess accumulation in biomass was 30 to 50% of TPL. The remainder originated from atmospheric deposition. Quercus had the highest annual TPL at all sites, mainly because of greater input of atmospherically derived acidity, but also by a greater cation excess accumulation in biomass. Carpinus, compared to Fagus and Quercus, tended to have the lowest TPL at all sites, and Tilia had the lowest TPL at the intermediate site.     

Water-soluble phenolic substances in soils under several coniferous and deciduous tree species

The humus layer of soils under Betula pendula, Quercus robur, Fagus sylvatica, Pinus nigra and Picea abies was analyzed for water-soluble phenolic substances. Highest concentrations of total water-soluble phenols were found in soils supporting oak trees. Highest polyphenol concentrations occurred under spruce-fir and beech trees, whereas highest monomeric phenols were found in soils under spruce-fir and pine. The polyphenol content was positively correlated with total carbon content of the soil. The phenolic acid composition of the soils under trees was partly dependent on the tree species. Among the monomeric compounds, ferulic, p-coumaric, vanillic, protocatechuic, syringic and benzoic acid dominated the phenol spectra.Seasonal variations were observed in the concentrations of water-soluble and mild alkaline-soluble phenols in the humus layer under F. sylvatica in two contrasting soil types. The water-soluble phenols in a sandy soil accounted for a larger proportion of the mild-alkaline extractable amounts compared to a loamy soil.     

Method to estimate atmospheric deposition of base cations in coniferous throughfall

A convenient non-electric method for estimating the dry deposition of base cations on a coniferous forest is presented. The dry deposition is estimated by multiplying the ratio of the base cation deposition to the sodium deposition on a surrogate surface with the dry deposition of sodium on the forest stand (throughfall technique). The surrogate surface is designed to resemble the needles in a coniferous forest with respect to particle deposition. Atmospheric non-marine dry deposition measured using the surrogate surface was compared to model calculated depositions. There was a good agreement for calcium but not for potassium.     

Mercury in forest canopy throughfall water and its relation to atmospheric deposition

A seasonal variation of both particle and gaseous Hg concentrations in the atmosphere is present in south-western Sweden. An average gaseous Hg level of 3.7 ng m⁻³ is found in winter, compared to 2.8 ng m⁻³ in summer. A weak decreasing south-north gradient for gaseous Hg in air over the Nordic countries is also present, with yearly average values from 3.2 to 2.8 ng m⁻³. A gradient for particulate Hg is less clear. An air parcel trajectory sector classification of gaseous Hg levels in air, and to some extent the particulate associated Hg, clearly demonstrates the increased concentrations in the southern sectors, especially in south-western Sweden where the gaseous Hg increase is about I ng m⁻³. These observations are consistent with an influence from the European continent. The average concentrations of Hg in precipitation at the various stations show a pronounced decreasing south-north gradient. A major portion of the total Hg present in precipitation is associated with particles. For the southern stations, a strong correlation between Hg and sulfate, or pH, is present suggesting a connection between Hg in precipitation and anthropogenic activities.     

Decomposition of sun and shade leaves from three deciduous tree species,as affected by their chemical composition

Freshly fallen leaf litter from sweet chestnut (Castanea sativa Mill), oak (Quercus robur L.) and beech (Fagus sylvatica L.) trees were classified into sun, intermediate and shade leaf types and analysed for N, acid detergent fibre, holocellulose, and lignin. In addition, the sugar constituents of structural polysaccharides (mainly from hemicelluloses) were determined after trifluoracetic acid (TFA) hydrolysis, and the phenylpropanoid (PPD) derivatives of lignin after alkaline CuO oxidation. The litters were decomposed in laboratory microcosms for 2 years. Decomposition rates were initially rapid and then plateaued, but differences in mass losses for the leaf litter categories, and between the three species, were significant at 6, 12, 18 and 24 months. Mean mass losses after 24 months were 49.6% for chestnut, 40.4% for oak and 26.3% for beech. Mean losses for chestnut, oak and beech litter categories were 48.6%, 38.2% and 24.6%, respectively, for sun leaves, and 51.0%, 44.5% and 28.5%, respectively, for shade leaves. Initial lignin concentrations showed a negative correlation with mass losses over the first 6 months but initial acid detergent fibre was a better predictor of decomposition rates after 24 months. Within species, however, total extractable sugars and PPD concentrations reflected differences in decomposition rates between the different categories of leaf types. The analysis for specific carbohydrates and lignin derivatives improved the resolution of litter quality characterisation but did not explain the observed patterns of decomposition in long-term laboratory incubations. It is suggested that these may be affected by influence of the culture conditions on the composition of fungal communities.     

Modelling interannual and spatial variability of leaf senescence for three deciduous tree species in France

The annual timing of temperate forest leaf colouring is affected by climate change; to date, its modelling remains a challenge. We take advantage of a ca. 400 leaf colouring observations database acquired in France during the period of 1997–2006 in order to develop a new modelling framework aimed at predicting the spatial and year-to-year variability of leaf colouring in European beech and oak (Fagus sylvatica L., Quercus petraea (Matt.) Liebl. and Quercus robur L.). We postulate colouring to be the outcome of a one-way process triggered by photoperiod and progressing through a photoperiod-sensitive cold-degree day summation procedure. Observations were pooled according to genus for the fitting and ensuing validation procedures. Parameters of the model suggest that colouring processes start earlier, and are sensitive to higher temperatures for Quercus than for Fagus. Errors associated with the modelled predictions are up to 13.0 days in Fagus and 10.3 days in Quercus, which are significantly lower than errors associated with (1) the overall mean (null model) or (2) previously published modelling frameworks. When averaged on a site basis, model predictions reproduced spatial variability of leaf colouring over the French territory with good efficiency (modelling efficiencies: 0.44 for Fagus, 0.45 for Quercus). The interannual variability of leaf colouring over France was fairly reproduced (r² = 0.74 for Fagus, 0.83 for Quercus). On that basis, we claim that the modelling framework developed herein can be efficiently integrated into more general schemes aimed at simulating matter and energy fluxes on a regional scale, and we provide a generic parameterisation of the model to be integrated into such schemes. When used in a prospective analysis, the model predicts a trend towards delay in leaf colouring of 1.4 and 1.7 days per decade in Fagus and Quercus, respectively, over the period of 1951–2099 in France.     

Interspecific variation of bark water storage capacity of three deciduous tree species in relation to stemflow yield and solute flux to forest soils

The purpose of the study was to: (1) test if normative bark water storage capacities differed significantly among three co-occurring deciduous tree species; and (2) examine the extent to which stemflow production and resulting solute inputs in temperate deciduous forests are affected by bark water storage capacity. Normative bark water storage capacities were determined for: Betula lenta L. (sweet birch), Carya glabra Mill. (pignut hickory), and Quercus rubra L. (northern red oak). Using the computed normative bark water storage capacities, previously published allometric equations relating tree diameter to aboveground woody surface area, and stemflow yield and chemistry data from ten precipitation events, the influence of bark water storage capacity on stemflow production and solute inputs was examined. Results demonstrated normative bark water storage capacities differed significantly among the tree species examined. Quercus rubra was found to hold the most water and B. lenta the least. For a 30 cm diameter tree, normative bark water storage capacities ranged from approximately 100 l for B. lenta to 250 l for Q. rubra. Despite a higher normative bark water storage capacity, Q. rubra was computed to have the largest stemflow solute inputs. Differences in stemflow quantities as well as solute inputs were attributable to interspecific variation in bark morphology and branching architecture, characteristics that affect amount of storage and detention times. Bark water storage capacity is linked with the geoecology of temperate deciduous forests because stemflow volume and solute inputs are partly determined by bark water storage capacity.     

Soil mixing and genesis as affected by tree uprooting in three temperate forests

The purpose of this study was to identify general patterns of pedoturbation by tree uprooting in three different, forested landscapes and to quantify post‐disturbance pedogenesis. Specifically, our study illustrates how the effects of ‘tree‐throw’ on soils gradually become diminished over time by post‐uprooting pedogenesis. We studied soil development within 46 pit‐mounds in two regions of the Czech Republic, one on Haplic Cambisols and one on Entic Podzols. A third study site was in Michigan, USA, on Albic Podzols. Uprooting events were dated by using tree censuses, dendrochronology and radiometry. These dates provided information on several chronosequences of pedogenesis in the post‐uprooting pits and mounds, dating back to 1816 AD (dendrochronological dating, Haplic Cambisols), 322 AD (median of calibration age, ¹⁴C age = 1720 ± 35 BP, Entic Podzols) and 4077 BC (¹⁴C age = 5260 ± 30 BP, Albic Podzols). Post‐uprooting pedogenesis was most rapid in pits and slowest on mounds. Linear chronofunction models were the most applicable for pedogenesis, regardless of whether the soils were in pit or mound microsites. These models allowed us to estimate the time required for horizons in such disturbed sites to obtain the equivalent thicknesses of those in undisturbed sites. These ranged from 5 (O horizon in pits on the Haplic Cambisols) to > 16 000 years (E horizon on mounds on the Albic Podzols). On the Albic Podzols, development of eluvial and spodic horizon thicknesses suggested that pathways involving divergent pedogenesis may occur at these small and localized spatial scales.     

Mechanisms of deposition of methylmercury and mercury to coniferous forests

Deposition of methylmercury (MeHg) and mercury (Hg) to a coniferous forest have been investigated using field measurements. Samples of open field (OF) wet deposition, throughfall (TF) and litterfall (LF) have been collected and analyzed for MeHg and Hg during the period November 1991 to April 1994. Average concentrations in TF were 22.8 and 0.38 ng L^?1, for Hg and MeHg, respectively. Concentrations in OF precipitation were 11.9 and 0.37 ng L^?1, for Hg and MeHg, respectively, during the same period. Considerable differences were found for Hg in TF and OF which was attributed to a dry deposition of Hg. Hg in LF contributes a deposition of equal size as in TF. The relations between OF, TF and total Hg deposition were approximately 1∶1,5∶3. A decrease in OF Hg was found over the three year period studied. MeHg deposition in OF was also found to decrease during the same period whereas the TF MeHg showed a slight increase. Dry deposition of MeHg is also an important process in a coniferous forest although the flux to the forest floor is not via TF but rather as MeHg in LF.     

Tree identity surpasses tree diversity in affecting the community structure of oribatid mites (Oribatida) of deciduous temperate forests

The role of tree diversity and identity as determinants of soil animal community structure is little understood. In a mature deciduous forest dominated by beech we identified clusters of one, two and three tree species of beech, ash and lime allowing to investigate the role of tree species diversity and identity on the density and community structure of oribatid mites. To relate oribatid mite community structure to environmental factors we measured leaf litter input, fine root biomass, mass of organic layers, topsoil pH and C and N content. We expected oribatid mite density to increase with increasing tree diversity, but we expected the effects of tree species identity to override effects of tree diversity. Further, we hypothesized the density of oribatid mites to be reduced by the presence of beech but increased by the presence of lime and ash. As expected tree diversity little affected oribatid mite communities, whereas tree species identity strongly altered density and community structure of oribatid mites. However, in contrast to our expectations the density of oribatid mites was highest in presence of beech indicating that many oribatid mite species benefit from the presence of recalcitrant litter forming thick organic layers. Especially Oppioidea benefited from the presence of beech presumably due to an increased availability of food resources such as fungi and nematodes. Lower density of oribatid mites in monospecific clusters of lime and ash suggests that oribatid mites did not benefit from high quality litter of these species. Notably, large and strongly sclerotized oribatid mite species, such as Steganacarus magnus and Chamobates voigtsi, benefited from the presence of ash and lime. Presumably, these large species better resist harsh microclimatic conditions in shallow organic layers.     

Inorganic Constituents of Well Water in One Acid and One Alkaline Area of South Sweden

Acid precipitation may lead to loss of essential elements and increase the concentrations of potentially toxic elements in drinking water. In this study 46 private wells from acid regions(pH < 6.5) were compared with 43 private wells from alkaline areas in southern Sweden. The concentrations of about 30 elementswere analysed especially by inductively coupled plasma opticalemission spectroscopy (ICP-OES). The concentrations of essentialelements such as calcium, chromium, selenium and potassium weresignificantly lower in acid than in alkaline well water. On theother hand, the levels of potentially toxic metals such as cadmium and lead were significantly higher in acid well water. High copper concentrations, observed at pH around 6 in contrast to earlier findings, is to be considered as an acidification problem, as should the high fluoride values. The highest concentrations of a number of metals and ions, for example calcium, chromium, titanium and sulphate, appeared at pH 7.0–8.0, where the peak in concentrations occur due to leachingof metals from soil particles in acid soils and precipitation ofcarbonates and sulphates in more alkaline soils. The low levelsof especially calcium and magnesium ions, and some micronutrientsin the acid water, in combination with high concentrations of acid ions and toxic microelements, may cause nutritional imbalances. This should be regarded as risk factors with relationto effects on human health.     

Estimates of atmospheric deposition and canopy exchange for three common tree species in the Netherlands

During one year, dry and wet deposition onto thirty forest stands is studied by sampling throughfall and bulk precipitation. Nine measurement sites are situated in Douglas fir (Pseudotsuga menziesii Mirb. Franco) stands, ten in Scotch pine (Pinus sylvestris L.) and eleven in Oak (Quercus robur L.) stands. Because the stands are situated in each other's proximity (i.e. within a radius of approximately 1.4 km) it is assumed that they experience an approximately equal air pollution load. For the acidifying compounds SO₄ ^2?, NO₃ ^? and NH₄ ⁺ spatial variability in wet deposition was small within the area studied. Dry deposition, as estimated by net throughfall, displayed a much higher spatial variability. Significant differences existed between tree species and growing seasons. Douglas fir mostly displayed the highest, Oak the lowest and Scotch pine intermediate values for net throughfall fluxes of acidifying compounds. The annual net throughfall fluxes for nitrogen compounds were significantly higher for the coniferous tree species than the broadleaved tree species. For SO₄ ^2?, however, Oak showed a relatively high throughfall flux during the summer. By comparing the temporal pattern of net throughfall fluxes between the three tree species it was concluded that considerable canopy leaching occurred for SO₄ ^2?, Mg⁺, PO₄ ^3?, HCO₃ ^? and K⁺ in Oak stands during the sprouting of leaves in spring. From surface wash experiments in the laboratory it is concluded that canopy leaching of these ions may also be enhanced when Oak leaves are infected by Oak mildew, a fungal disease caused by the fungus Microshaera aliphilitoides.     

Sensitivity of forest-floor mosses in boreal forests to nitrogen and sulphur deposition

The response of forest-floor mosses to deposition of nitrogen (N) and sulphur (S) was examined in field conditions in a 60-year-old Norway spruce (Picea abies Karst.) stand in southern Finland. The experimental plots received nitrogen (25 kg N ha^–1) and sulphur (30 kg S ha^–1) as ammonium sulphate once a year for 4 years.The dominant moss species on the site were Pleurozium schreberi (Mitt.) and Dicranum polysetum (Sw.). The biomass of the dominant moss species was decreased significantly by N and S deposition during the study period. Due to the addition of N and S, the biomass of Pleurozium schreberi was decreased by 60% and the biomass of Dicranum polysetum by 78%.     

Sewage sludge as a fertilizer of pole stage forests: short-term hydrochemical fluxes and foliar response

Abstract. Proposed restrictions on the disposal of sewage to the marine environment means that alternative land based outlets are required in the UK. Commercial forestry represents a significant land use that could receive and benefit from the application of sewage sludge, to overcome the generally poor soil nutrient status. The oligotrophic and sensitive nature of surface waters in many afforested areas requires that the environmental consequences of the widespread use of organic fertilizers in forestry are carefully considered. This paper compares the effects of an N and P fertilizer with that of sewage sludge on the nutrient content of foliage in a pole stage Scots pine ( Pinus sylvestris ) forest and of nutrient fluxes in soil. Both conventional fertilizer and sewage treatments had significant but differing effects on the availability and leaching of the major nutrients, especially N and P. Evidence for increased nitrification and nitrate production with time was apparent for both treatments. Fluxes of N and P in mineral horizon leachate were consistently smaller than those from the overlying organic horizon. Foliar nutrient concentrations after one year were significantly higher ( P < 0.01) in all of the treatments, and conventional fertilization with urea produced a significantly higher foliar N concentration than that measured in the sludge-treated plots. There was no evidence for appreciable N or P leaching from the site within a year of sludge application.     

Concentrations of 60 elements in the soil solution as related to the soil acidity

Little is known about solubility and soil solution concentrations of most elements occurring in the solid phase of soils. This study reports changes in solution concentrations of 60 mineral elements following CaCO₃ addition to a moderately acid semi‐natural soil, and possible mechanisms accounting for the differing solubility patterns as related to soil acidity are discussed. Soil solutions were obtained by high‐speed centrifuging and ultrafiltration (0.2 μm) of samples at 60% water‐holding capacity of the A horizon of a Cambisol developed from a shale–gneiss moraine and supplied with CaCO₃ at 20 rates to yield a soil solution pH range of 5.2–7.8. Concentrations of elements were determined in the solutions by ICP‐AES or (for most elements) ICP‐MS. Several distinct patterns of soil solution concentrations as a function of soil solution pH were demonstrated. Positively related to pH and CaCO₃ supply were soil solution concentrations of As, Br, Mo, S, Sb, Se, U, and W, and to a lesser degree, Co, Cr, Hg, Mg, and Sr. Inversely related to pH were concentrations of Al, B, Ba, Bi, Cs, Ce, Eu, Ga, Ge, Fe, Li, K, Rb, Na, Th, and Ti; less distinctly inversely rated were Dy, Er, Gd, Hf, La, Lu, Mn, Nd, Pr, Sm, Sc, Si, Tl, Tm, and Yb. ‘U‐shaped’ relationships to pH were demonstrated for the concentrations of Ag, Cd, Nb, Ni, P, V, and Zr. There were no or irregular relations between pH and concentrations of Be, Cu, Ho, Pb, Ta, and Tb. Differences between elements in their soil solution concentrations as related to total (HNO₃‐digestible) concentrations and the solubility of organic C were also treated. Increasing the pH of a soil by adding CaCO₃ changes the solubility of most mineral elements substantially, the several distinct patterns observed being governed by, for example, ionic properties and charge, affinity for organic compounds, and pH‐dependent formation and solubility of complexes.     

The effect of stand structure and tree species composition on epiphytic bryophytes in mixed deciduous-coniferous forests of Western Hungary

The effect of tree species, stand structure, landscape and historical variables was studied on the species composition, species richness and cover of epiphytic bryophyte assemblages in mixed deciduous-coniferous forests of Western Hungary. Stand and tree level assemblages were analyzed by ordinations and generalized linear modeling in 35 70-110 year old stands of different management regimes.Bryophytes showed a considerable preference to different host trees, so that stand level diversity of bryophyte assemblages was determined mainly by tree species diversity, and their composition by tree species composition. Cover and diversity of epiphytic bryophytes were the highest on oaks (Quercus petraea and Quercus robur), and the lowest on Scotch pine (Pinus sylvestris). The presence of sapling (shrub) layer increased, whereas a large number of medium sized trees decreased bryophyte species richness in this study. Tree size was much less influential which is explained by the lack of large, veteran trees. Forest management maintaining tree species diversity, structural heterogeneity and temporal continuity of the stands could considerably contribute to the conservation of this organism group. Selective cutting is more appropriate for these conservational purposes than shelterwood management system.     

Responses of oribatid mites to tree girdling and nutrient addition in boreal coniferous forests

Tree girdling has been experimentally used to stop the allocation of carbohydrates from the canopy to tree roots and their associated ectomycorrhizal (EM) mycelia. We used three already established girdling experiments in northern Sweden, one in a Pinus sylvestris stand and two in Picea abies stands, to determine the effect of tree girdling on soil-living oribatid mites. These mites often feed on fungal hyphae, but it is not known to what extent they feed on EM or saprotrophic fungi. We hypothesised that a presumed decline in EM fungi after girdling would strongly reduce EM-feeding specialists and, correspondingly, reduce total abundance and species richness of oribatids in girdled plots. Tree girdling resulted in a significant decline in total abundance of oribatid mites in the two spruce stands, which was assumed to be linked to the decline in EM fungi, but not in the pine stand. Species richness decreased in girdled plots in one of the spruce forests. The decline in total abundance in girdled spruce stands was primarily dependent on a significant and consistent population decrease in Oppiella nova, which was the most abundant oribatid mite in the ungirdled spruce plots. Its abundance after girdling was only 8–18% of that in ungirdled spruce plots. In the pine stand, O. nova had much lower abundance than in the spruce stands, and despite a tendency to decline in number after girdling also in the pine stand, it had a minor effect on total abundance. These results suggest that O. nova may be dependent on EM fungi in spruce forest soils, whereas the dependence on EM fungi in pine forest soils is less evident.     

Carbon stock and deposition in phytomass of the Russian forests

Russian forests occupy an area of 771 Mha with a wood volume of 81.6 × 10⁹ m³. In this paper we estimate the carbon (C) storage and annual C deposition in living vegetation for stands of different age groups according to information in the Russian National Forest Inventory (NFI). Conversion of root C storage into phytomass was based on phytomass/storage ratios calculated from data from 1900 test areas in the different forest regions of Russia. We developed these conversion ratios for different phytomass fractions, namely: stems, branches, roots and foliage, for different forest forming species. Of the total forest area (771 Mha), C storage in the living phytomass is 35.07 Pg C. Total annual C deposition in forest vegetation is estimated at 213.2 Tg C. We considered the role of the main forest forming species in the C cycle of the forest vegetation taking into account the actual structure of the Russian forests.     

Carbon pools and fluxes of 25-year old coniferous and deciduous stands in middle Siberia

Between 72 and 88% of carbon (C) loss in forest litter decomposition returns to the atmosphere in the form of carbon dioxide. The share of water-soluble organic products does not exceed 3–4%. Between 8% under spruce and 25% under aspen and pine of the total C loss from litter organic matter goes to the formation of humus. Decomposition intensity of the dead organic matter on the soil surface is close to annual litterfall income (except under cedar). The specific rate of decomposition processes among the coniferous litters is minimum for cedar (167 mgC g^?1yr^?1) and maximum for larch (249 mg C g^?1 yr^?1). The specific rate of decomposition of organic residues under aspen and birch canopies are 344 and 362 mg C g^?1yr^?1.     

Soil acidification and element fluxes of a Fagus sylvatica forest as influenced by simulated nitrogen deposition

Water, Air, &; Soil Pollution - The influence of simulated 3- and 9-fold increases in the current N deposition on element fluxes and soil acidification was investigated in a beech forest in S...