Water relations of Yezo spruce and Todo fir in declined stands of boreal Forest in Hokkaido, Japan

Recently, symptoms of decline have been widely observed in Yezo spruce (Picea jezoensis) and Todo fir (Abies sachalinensis) in Hokkaido. In order to clarify the mechanism of decline, the water status of Yezo spruce and Todo fir trees in the Tokyo University Forest in Hokkaido were investigated. The decline is observed mainly in stands damaged by Typhoon XV of 1981 (D-stands), but is not observed in undamaged stands (C-stands). Sampled trees in both types of stands were selected, the severity of their decline estimated, diurnal water potentials measured and water relation parameters such as water potential at turgor-loss point ( ) and osmotic potential at full saturation ( ) were estimated by pressure-volume analysis. The diurnal trends of leaf water potential and midday water potential ( ) of the sample trees were clearly different between the D-stands and the C-stand. Water stress in trees was much more severe in the D-stands than in the C-stand. and of the declining trees were lower in the D-stands than in the C-stand. However, and were not significantly different between declining trees and healthy-looking trees in D-stands. It was concluded that stand-level water stress, induced by the destruction of the canopy by the typhoon, was associated with the decline symptoms. The measurement of water relation parameters proved to be useful for diagnosis and prediction of decline at a stand level in this area.     

The enzymatic degradation of cellulose from Valonia ventricosa

Summary The degradation of microfibrils from Valonia ventricosa by cellulase has been studied. As a result of enzymatic attack the elementary fibrils making up the microfibrils tended to separate and the ends of the microfibrils became oblique or pointed. The terminal planes made angles of 60 ... 66°, 33°, or 20 ... 25° with the microfibril axis. These planes are assumed to correspond to the 41 , 43 and 45 planes of the cellulose lattice and it is suggested that they are planes along which it is progressively more difficult for hydrolysis to proceed. On the basis of these considerations a suggestion has been proposed to explain the form of erosion cavities formed by soft-rot fungi described by previous workers in wood fibres and tracheids.

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Zusammenfassung Der Cellulase-Abbau von Mikrofibrillen aus Valonia ventricosa wurde untersucht. Die enzymatische Wirkung führt dazu, daß die Elementarfibrillen, welche die Mikrofibrillen bilden, eine Tendenz zur Ablösung zeigen und daß die Enden der Mikrofibrillen schräg oder spitz zulaufen. Die Endflächen bilden mit der Mikrofibrillenachse Winkel von 60 ... 66°, 33° oder 20 ... 25°. Es wird angenommen, daß diese Flächen mit den Ebenen 41 , 43 and 45 des Cellulosegitters übereinstimmen und daß entlang dieser Ebenen die Hydrolyse zunehmend schwieriger wird. Aufgrund dieser Überlegungen wird eine Hypothese entwickelt, welche zur Erklärung der von den Moderfäulepilzen erzeugten, erosiven Vertiefungen dient, die bereits in verschiedenen Arbeiten über Holzfasern und Tracheiden beschrieben wurden.

     

Genetic parameter estimates for growth and form traits in common ash (Fraxinus excelsior, L.) in a breeding seedling orchard at Little Wittenham in England

Data from a trial of 36 families at Little Wittenham, North Oxford was used to assess growth traits and stem form in common ash (Fraxinus excelsior, L.). The trial followed a design described by Barnes (Silv Genet 44(2–3):81–88, 1995) as the Breeding Seedling Orchard (BSO). The objectives of the study were to determine variation in growth and form traits and estimate genetic parameters of families. Assessments conducted at 3–8 years for height, diameter at breast height (dbh), straightness and forking showed significant differences (P < 0.05) among families with Guys (19), Settrington (34), Overbury (23) and Grimthorpe (36) being the best performers while Coleford (3 and 5) Gwynedd (27) and Bacheiddon (32) were the least performers. At the overall level, the additive genetic coefficient of variation (CV_A) ranged between 10.2 and 12.7% for height and 1.5 and 2.1% for dbh. Height had a high genetic correlation (r_g = 0.85) with dbh whilst forking had low correlation (r_g = 0.25) with height. Estimates of heritability decreased with age from  = 0.62 at 3 years to  = 0.30 at 8 years for height while values for dbh decreased from  = 0.48 at 4 years to  = 0.27 at 8 years. Some genetic gains are possible despite the low genetic variation among families; height had the greatest potential of genetic gain (12.5% at 8 years). Results suggest that early selection of superior families of Fraxinus excelsior appears to be feasible and it could be possible to achieve simultaneous improvement in both growth and form.     

Moisture extraction and crop yield as a function of distance from a row of Eucalyptus tereticornis

A study was made on the effect of an east-west tree line of years old Eucalyptus tereticornis on soil physical parameters and adjoining mustard and wheat crops as a function of distance from the tree-crop interface in north- and south-facing sides. Maximum soil temperature, pan evaporation, moisture extraction, number of plants/m², and yields of mustard and wheat did not differ significantly on the two sides of plantation. Plant growth parameters decreased linearly with distance from the plantation. Mustard yield, Y (kg/ha) was linearly related to moisture extraction, ME (mm) as Y = 1914–120.3 ME. Eucalyptus tereticornis was found to extract 5 times more water than mustard from 0–150cm soil profile. Mustard and wheat yield reductions in adjoining 10 meter strips on both sides of the plantation were 47 and 34 per cent, respectively. Eucalyptus tereticornis is, therefore, not a suitable species for row plantations in agro-forestry systems in deep water table conditions of semi-arid regions.     

Linearity and non-linearity in mechano-sorptive creep of softwood in compression and bending

Summary Non-linearity of softwood in axial mechano-sorptive creep during moisture cycling can be characterised as departure from linear behaviour. Linear behaviour is shown by experimental measurement to be a gradual approach to a creep limit with exponentially decreasing increments of compliance, J_i, per moisture cycle, when tested under a constant stress. On the other hand, when the stress is progressively increased by a small increment after each moisture cycle, the compliance increments will progressively increase, having a value of , where n is the cycle number. By subtracting one compliance increment from the succeeding one, the value of J_i can be obtained. Analysis of experimental results in bending tension and compression showed that the compression test pieces departed from linearity at total strains around 0.14% to 0.15%, the bending test pieces showed slight evidence of non-linearity at about the same strain, whilst the tensile pieces were approximately linear up to 0.18% strain.This project was supported by the U.K. Science and Engineering Research Council and by the European Commission     

Preparation and characterization of the phenolated wood using hydrochloric acid (HCl) as a catalyst

Summary Birch (Betula maximowicziana Regel) wood meal was liquefied in the presence of phenol using hydrochloric acid (HCl) as a catalyst at a temperature of 150 °C for 2 h in an autoclave. It was found out that HCl acid could be used as an effective catalyst for the hydroxy phenylation of wood under the experimental conditions. In this study the effect of the concentration of the acid catalyst and the phenol-to-wood ratio on the liquefaction were investigated. The results showed that the phenol-to-wood ratio and the concentration should be increased to a certain degree in order to achieve a less residual rate and sufficient amount of combined phenol. The phenolated woods had apparent flow temperatures in the range of 134.4 to 199.8 °C, being higher than that of a commercial novolak resin. Furthermore, increases in the HCl concentration during liquefaction reaction led to increase in the apparent flow temperature of the resulting phenolated woods. However, the changes in the liquid ratio did not bring about evident changes. The relationship between shear stress (τ) and shear rate showed that the phenolated wood resin melts were shear thinning fluids. The dependences of the apparent melt-viscosities (η) of the phenolated woods and a commercial novolak resin on the shear rates ( ) have the similar tendencies, however, it was found the viscosities of the phenolated woods are about one order higher than that of commercial novolak resin.     

Osmotic stress in wood — part II: on the computation of drying stresses in wood

Summary Plastic stress arising in wood during drying is calculated according to the theoretical model developed earlier. The mechanism of stress reversal and the type of resudual stress corresponding to different values of material constants are shown. The results are in qualitative agreement with experimental evidence.List of symbols A coefficient of swelling below the fibre saturation point - C concentration of moisture in wood; weight of moisture per weight of dry wood - C ₀ uniform concentration of moisture in wood at the beginning of drying - C ₁ equilibrium concentration of moisture at the boundary during drying - C =C-C ₁ - non-dimensional concentration - D diffusivity - D ₀ first term in the expansion of diffusivity as function of concentration: D=D ₀(1+D ₁ C+...) - D ₁ secondterm in the expansion (see D ₀) - E Young's modulus - e _ij deviator of tensor of strain: - e _ij ^P deviator of plastic strain: - e _ij ^E deviator of elastic strain - F fibre saturation point (concentration at which the function (c) changes slope) - F =F-C ₁ - g(x,t) function which assumes the value 1 in the elastic zone and 0 in the plastic zone - k von Mises' yield stress - L half width of the sample - M total moisture content - P plastic power - S _ij deviator of stress - S _kk =S ₁₁+S ₂₂+S ₃₃ - S _ij ^E =2 e _ij - T _ij tensor of stress - T _kk =T ₁₁+T ₂₂+T ₃₃ - T non-zero component of stress in a beam or plate - non-dimensional stress - actual stress rate in an elastic zone, fictitious stress rate in a plastic zone - t time - t increment of time - x y z spatial coordinates - X increment of spatial coordinate - Y - Y ₀, Y ₁ terms in the expansion of Y(C): Y(C)=Y ₀(1+Y ₁ C+...) - non-dimensional Y - , (c) coefficient of osmotic expansion (dependent on concentration) - _ij tensor of strain - _kk =₁₁+₂₂+₃₃ - =_yy=_zz non-zero component of strain in the case of a plate or beam - modified strain - elastic constants of an isotropic body - non-dimensional spatial coordinate - Poisson's ratio - non-dimensional time     

Causes for the small scale variability of nitrate concentration in seepage water of an N saturated mature spruce stand

Context

In N-saturated forests nitrate concentrations in seepage water ( $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ ) regularly show high spatial variability even within homogeneous stands. Up to now the reasons of this variability are not fully understood.

Aims

The main objective was to identify the crucial parameters that control spatial variability of $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ at the H?glwald site.

Methods

We investigated a multitude of parameters (e.g. N turnover, root biomass, soil chemistry, soil physics, stand parameters) and related them to $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ , measured in 40?cm depth with suction cups.

Results

A small number of biological parameters (net N mineralization, root distribution, and stand density) explained up to 93?% of the variability of $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ in linear regression models. Net N-mineralization rates in the humus layer and fine root biomass in the upper mineral soil influenced $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ positively. Fine root biomass in deeper soil layers (30?C40?cm depth) and stand density had a negative influence.

Conclusion

The rate of net N mineralization in the organic layer is decisive for the nitrate production in the soil. Roots in the upper mineral soil increase $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ by intensive water uptake but excluding nitrate at the same time. The variation of these two parameters is responsible for most of the small-scale variability of $ {\text{N}}{{\text{O}}_3}{^{ - }_{\text{seepage}}} $ .     

Relationship between degradation of wood and production of H2O2-producing or one-electron oxidases by brown-rot fungi

Summary The one-electron oxidation activity of brown-rot fungi was determined by measuring ethylene production from KTBA. Ethylene production was related to degradation of lignin, cellulose, and wood itself. Extracellular protein that catalyzed oxidation of KTBA was isolated from wood-containing cultures. This protein required H₂O₂ for KTBA oxidation. It was also found to oxidize NADH, producing H₂O₂ via in the presence of O₂. The protein showed little phenol-oxidase activity under conditions giving high activity against KTBA. The results indicate that partially reduced oxygen may play a role in the initial degradation of the cellulose and lignin in wood in cultures of brown-rot fungi.     

Scaling-up method for stand water consumption of Quercus variabilis water conservation forest

Single tree’s sapwood scattering style and diurnal water consumption rhythm for different diameter classes were studied in a 48-year-old Quercus variabilis stand, water protection forest in Beijing. Results showed that the tree’s sapwood area was closely related to diameter at breast height (DBH). Single tree’s daily water consumption ascended as DBH and sapwood area increased. Daily water consumption of different diameter classes in September ascended steeply in the early morning and reached the peak around 11:00, and then descended slowly to the valley at 18:00. The course of daily accumulated water consumption was in accordance with a typical Richards model (R=0.985,8). Parameters of diameter-time equation for scaling-up can be achieved by parameter-recovering method in the gradient of all diameter classes and at any time of a day, characteristic parameters of the course of daily stand water consumption were calculated from a modulated Richards equation derivative:

Mögliche Gefährdung der Umwelt durch Pflanzenschutzmaβnahmen

Zusammenfassung Es wird untersucht, welche Bedeutung die in Zukunft sicher noch zunehmende Anwendung von Pflanzenschutzmitteln in der BRD für Boden und pflanzliche Nahrung hat.Die Anwendung der vieldiskutierten Insektizide spielt nur eine sehr geringe Rolle (5% der verwendeten Pflanzenschutzmittel). Fast der Mittel sind Herbizide, der Rest Fungizide, die meist in Boden und Pflanze schnell abgebaut werden.Nur auf etwa 3–4% der Bodenfläche, bzw. 5–7% der LN kann mit Rückständen durch Verwendung persistenterer Mittel gerechnet werden.Ein großer Teil der mit Pflanzenschutzmitteln behandelten Feldkulturen dient nicht direkt der menschlichen Ernährung, sondern wird als Viehfutter verwendet. Etwaige Rückstände sind für den Menschen ohne Bedeutung.Rückstandsuntersuchungen der pflanzlichen Nahrung haben ergeben, daß nur in ganz wenigen Fällen die Toleranzen überschritten wurden, Aber dies bedeutet noch keine Gefährdung, da diese Toleranzen weit unter der akut toxischen Menge liegen und dauernde Aufnahme gleicher Früchte mit gleichen Wirkstoffen nicht wahrscheinlich ist.Die Betrachtungen haben gezeigt, daß bei sachgemäßer Anwendung von Pflanzenschutzmitteln mit einer Gefährdung von Boden und pflanzlicher Nahrung durch diese nicht zu rechnen ist.

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Summary The use of pesticides in the Federal Republic of Germany will almost certainly increase still further in future. Its effect on plant produce and soil is being investigated.The use of the much-discussed insecticides plays only a very small part in this (only 5% of all pesticides used). Almost of the products are herbicides, the rest fungicides, which are mostly broken down rapidly in plants and the soil.Following application of persistent compounds, residues can be expected in only 3–4% of the total land surface, i. e. 5–7% of the farmland.A large proportion of crops treated with pesticides are not intended for direct human consumption but are used as animal fodder. Any residues occurring here are of no significance to man.Residue analysis of plant produce revealed that in only a very few cases was the tolerance level exceeded. This does not, however, incur any risk, as the tolerances are well below the acute toxic levels, and prolonged consumption of the same crops treated with the same pesticides is unlikely.Experience has shown, that there is no risk to plant produce and soil if pesticides are applied in the proper manner.

     

Variation in seed production among years and among individuals in 11 broadleaf tree species in northern Japan

Seed production is the most problematic part of tree regeneration and is the least amenable to control by silvicultural management. Understanding variability in seed production among years and among trees will allow better planning of seed collection for seedling production and natural regeneration. We estimated the extent of variability in seed production among years and within years among individual trees. Specifically, we measured individual annual seed production in 11 woody species in Hokkaido, northern Japan. We analyzed the coefficient of variation (CV) of seed production among years and among individual trees. We used population- and individual-based CVs (CV_pt and ) to estimate the variability in seed production among individual trees. Alnus hirsuta, in which these CVs among trees were maximal, will require further analyses of the spatial patterns of seed production among individual trees. Additionally, we used population- and individual-based CVs (CV_py and ) to estimate the variability in seed production among years. The was statistically higher than in 2 of the 11 species: Betula maximowicziana and Sorbus alnifolia. Activities for the regeneration of these species should regard the annual variation in seed production as more important than individual variation. For the nine species in which was similar to even if seed production by specific trees was not sufficient for regeneration in a particular year, other trees or stands often had high seed production in that year. We discuss the relative importance of annual and individual variability in determining efficient methods for artificial and natural regeneration of these woody plant species.     

Characterization of cellulose in compression and opposite woods of a Pinus densiflora tree grown under the influence of strong wind

Summary Structural factors in a Pinus densiflora tree grown under the influence of strong wind were measured. No difference for cellulose molecules was noticed between compression and opposite wood, but the was somewhat lower in the region where the compression wood was concentrated. The degree of crystallinity of cellulose was 45–50% in compression wood, about 50% in normal wood, and 50–60% in opposite wood. The crystallinity decreased with increasing height above the ground. The maximum point of crystallographic b-axis (fiber axis) orientation distribution for cellulose crystallites in compression wood was located at 30°, in normal wood at 25° and in opposite wood at 0°. The cellulose crystallite dimension in the transverse direction was 3.2 nm, corresponding to four cellulose unit cells, a value that was almost constant throughout the wood. In the longitudinal direction, there were large differences in cellulose crystallite dimensions between compression and opposite woods. In compression wood the cellulose crystallite dimensions was 12 nm corresponding to 11–12 cellulose unit cells. In opposite wood it was 17–32.5 nm corresponding to 17–32 cellulose unit cells. These structural factors were apparently affected by the environmental conditions, and the mechanical properties of the wood were influenced by these factors. Opposite wood had longer crystallites, a higher degree of crystallinity and a better orientation distribution of cellulose crystallites in the longitudinal direction. Compression wood, on the other hand, had shorter crystallites, a lower degree of crystallinity and a large angle between the stem and the direction of the crystallites.     

Distribution of small mammals in a silvoarable agroforestry system in Northern England

The importance of agroforestry systems in temperate regions in providing habitat for small mammals has not been investigated. Numbers and densities of small mammals were assessed by live trapping in a complex farming landscape including mature hedgerows, arable fields, areas of trees planted at forestry density (2,500 trees ha–1) and trees in an agroforestry configuration (178 trees ha^–1) consisting of rows of trees separated by arable alleys. Over a 2 -year period, 1680 animals were captured; 69% were Apodemus sylvaticus L., 20% Sorex araneus L. and 10% Clethrionomys glareolus Schreber. Small numbers of Mus domesticus Rutty, Sorex minutus L., and Neomys fodiens Pennant were also caught. The density of captures of A. sylvaticus and S. araneus varied little over the whole farming landscape in contrast to C. glareolus which had a greater density of captures in mature hedgerows. However, for the small mammals collectively, away from hedgerows, the highest density of captures was found in the agroforestry tree rows (15.5 per 100 trap nights) and the least in open arable crop (4.3), with both arable alleys and forestry density trees having intermediate values (9.1 and 9.2 respectively).Densities of captures of A. sylvaticus were greater in the tree rows and arable alleys than in the forestry area and the adjacent open arable crop, whereas for S. araneus they were greater in the habitats with trees. It is clear that the range of habitats in an agroforestry system is valuable for small mammal conservation.     

A new composite k-tree estimator of stem density

This study presents a generally applicable and robust k-tree composite estimator of density. We propose to estimate stem density by a weighted average $ \left( {\hat{\lambda }_{\text{aic}} } \right) $ of 16 individual density estimators. The weights given to individual estimators are inversely proportional to the relative fit (Akaike’s corrected information criterion) of each estimator to the assumed distribution of observed k-tree distances. The performance of the proposed estimator is evaluated in simulated simple random sampling with k?=?3 and 6 in 58 forest stands (54 actual and 4 simulated) and 600 replications. Sample sizes were 15 and 30 locations per stand. Eleven estimators were novel, including three designed for regular spatial patterns. Absolute stand-level bias with k?=?6 varied from 0.1 to 8.1% (mean 1.8%), and a bias larger than 6% was limited to 3 stands with either pronounced density gradients or a strong clustering of stem locations. Root mean squared errors were approximately 16% (k?=?6 and n?=?15) versus 12% for sampling with comparable fixed-area plots. Coverage of computed 95% confidence intervals ranged from 0.72 to 0.99 (median?=?0.98 with n?=?15 and 0.95 with n?=?30), with 98% of all intervals achieving a coverage of 0.85 or better. In seven stands used in an assessment of a novel spatial point pattern reconstruction k-tree density estimator (RDE) by Nothdurft et al. (Can J For Res 40:953–967, 2010), the average absolute bias of $ \hat{\lambda }_{\text{aic}} $ with k?=?6 was 1.5 versus 0.7% for $ \hat{\lambda }_{\text{RDE}} $ .     

Use of trioxane for improvement of hygroscopic and acoustic properties of wood for musical instruments

Summary As a reagent source for the formalization of wood, trioxane was used instead of conventional paraformaldehyde. From preliminary experiments it became apparent that trioxane depolymerizes to formaldehyde by heating in the presence of some metallic salts. Formalization of wood with trioxane was carried out under the catalysis of sulfur dioxide (SO₂) along with these salts. The hygroscopic and acoustic properties were considerably improved by the treatment. Especially when the reaction was catalyzed by a combination of SO₂ and Fe₂(SO₄)₃, the antiswelling efficiency (ASE) reached nearly 70%, the specific dynamic Young's modulus (E/) in the radial direction increased about 20%, and the loss tangent (tan ) decreased about 30% and 50% in the longitudinal and radial directions, respectively. In this case, the modulus of rupture did not appreciably decrease in the radial direction. This is comparable to the most prominent results obtained so far by SO₂ catalyzed formalization with tetraoxane. It can be concluded that trioxane is very effective as a reagent source for formalization. The increase in acoustic converting efficiency, , of about twofold in the radial direction and decrease in hygroscopicity of more than 60% should not only enrich the sound volume of musical instruments but also stabilize their tone quality against humidity changes.     

Strain analysis near the cutting edge in orthogonal cutting of hinoki (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>) using a digital image correlation method

A digital image correlation (DIC) method was utilized to measure strain distributed within approximately 0.5 mm of the cutting edge during slow-speed orthogonal cutting of air-dried hinoki (Chamaecyparis obtusa), to clarify the relationships of the strain distribution and cutting conditions, including cutting angle (\(\theta\)) and depth of cut (\(d\)). The strain was measured in 0.04 mm steps, and the measurable minimum strain was approximately 0.08%. Tensile strain of 3% or larger normal to the cutting direction, \({\varepsilon _y}\), tended to extend 0.2 mm or further ahead of the tool when \(\theta \leq 60^\circ\) and \(d \geq 0.1{\text{ mm}}\). This tensile \({\varepsilon _y}\) corresponded to the occurrence of the fore-split in Chip Type I. The tensile \({\varepsilon _y}\) detected along the path of the cutting edge decreased as \(\theta\) and/or \(d\) decreased. Positive shear strain, \({\gamma _{xy}}\), tended to be detected ahead of the tool in Type I. Negative \({\gamma _{xy}}\) tended to be detected ahead of the tool in Type II and III \(\left( {\theta \geq 70^\circ ,\,\,d \geq 0.05{\text{ mm}}} \right)\). These \({\gamma _{xy}}\) values were considered to be related to the elongation and shrinkage of the chip. The study confirmed the usability of the DIC method for the evaluation of cutting conditions and also to classify chip formation into chip types.     

High organic carbon stock in a karstic soil of the Middle-European Forest Province persists after centuries-long agroforestry management

Little is known on soil organic carbon (SOC) stocks in karst areas worldwide, although many of them have seen long-term application of agroforestry systems with a potential for carbon sequestration. Therefore, our study aimed to assess landscape-level SOC concentration and stock in the Silica Plateau, a part of the Slovak Karst Biosphere Reserve located in the Western Carpathians (Slovakia) with a centuries-long agroforestry record. The most represented local soil units are Chromi-Rendzic Leptosols and Chromic Cambisols with clayey loam texture, C/N ratio 9–12, and $ {\text{pH}}_{{{\text{H}}_{2} {\text{O}}}} $ 6.6–6.2 in their organo-mineral surface horizons. Mull surface humus form prevails under mixed forest stands dominated by hornbeam (Carpinus betulus L.), oak (Quercus petraea L.), and beech (Fagus sylvatica L.). A total of 2,700 soil samples were collected from 150 soil pits. Both SOC concentrations and stocks were determined for the 0–60?cm mineral soil layer. Soil stoniness was accounted for by means of electrical resistivity tomography. According to the analysis of covariance, cropland SOC concentration (0.026?g?g^?1) is significantly lower compared to forestland (0.040?g?g^?1) and pastureland (0.041?g?g^?1) (P?<?0.01). During the period of 130?years after forest clearing, cropland SOC stock has been reduced at an exponential decay rate of ca 0.002?year^?1, while the SOC stock in pastureland has increased following land use change from cropland by approximately 30% during the same period of time. Irrespective of land use history, overall SOC stock is high reaching on average 207.4?Mg?ha^?1, out of which 66% are stored within 0–30?cm and 34% within 30–60?cm soil layers.