Mixture Of Birch Research Articles

Ecological typology of woody vegetation of the Starohut forest massif as a component of the restoration of disturbed ecotopes

The study aimed to determine the typological structure of the Starohut forest massif within the Desniansko-Starohutskyi National Nature Park based on the Ukrainian school of forest typology by Alekseev-Pogrebnyak. The massif covers an area of 6,778.8 hectares. The following trophotopes were identified in the study area: bors, subors, and sugruds. Bors, consisting of pine communities with some birch, occupy dry and fresh hygrotopes on flat terrain, covering 1.8 hectares or 0.02% of the total forest area. Subors, comprising pine-oak communities with birch and aspen, are found in fresh, moist, damp, and swamp hygrotopes, covering 4,510.1 hectares or 66.53% of the territory. Sugruds, consisting of oak-pine-lindenmaple forests on plains and aspen-birch-linden-maple forests in depressions, cover 2,266.9 hectares or 33.44% of the Starohut forest massif. No gruds were identified. The study found that the primary forest-forming species in the national park is Pinus sylvestris, occupying 5,092.7 hectares. Betula pendula covers 1,207.1 hectares, Alnus glutinosa – 201.4 hectares, Picea abies – 111.5 hectares, and Quercus robur – 90.0 hectares. Other tree species are sparsely represented. In the protected area of the park, fresh subors and sugruds dominate, including a mixture of birch, black alder, and spruce over a total area of 1,181.1 hectares, along with moist pine-birch-alder-oak subors and sugruds covering 849.4 hectares. The recreational zone is dominated by fresh hygrotopes with subors and sugruds totalling 2,336.4 hectares. In the economic zone, subors and sugruds prevail on fresh sandy soils, totalling 430.7 hectares. The results support the restoration of natural forest types in areas affected by large-scale fires in 2023-2024 and other anthropogenic influences

Tolerability and Safety of Sublingual Immunotherapy in Patients with Tree Pollen Allergy in Daily Practice-An Open, Prospective, Non-Interventional Study.

To investigate the tolerability and safety of two sublingual tree pollen extracts approved in 2018, a non-interventional study (NIS) was performed. This NIS was an 8-month observational study conducted at 84 sites throughout Germany. Study participants received either a sublingual liquid allergen extract of birch pollen (SBPE) or a liquid allergen extract consisting of a mixture of birch, hazel, and alder tree pollen (STPE). Data from 432 patients were analyzed for the occurrence of adverse events and patient compliance. At least one local reaction occurred in 69 (22.2%) patients, whereas systemic reactions were only observed in 27 (6.3%) patients. STPE-treated patients developed systemic reactions more frequently than SBPE-treated patients (SBPE: 9 (4.3%) vs. STPE: 18 (8.0%)). Only one patient developed a systemic grade III reaction. Severe systemic grade IV reactions were not observed. A total of 348 (98.6%) of the patients who completed all visits were satisfied or very satisfied with the sublingual immunotherapy (SLIT), and 322 (71%) patients completed all visits. Both investigated products were well tolerated by the patients and demonstrated a good safety profile. AEs were observed less frequently than in the preceding clinical phase III trial, and no new safety concerns were identified.

Pollen observations at four EARLINET stations during the ACTRIS-COVID-19 campaign

Abstract. Lidar observations were analysed to characterize atmospheric pollen at four EARLINET (European Aerosol Research Lidar Network) stations (Hohenpeißenberg, Germany; Kuopio, Finland; Leipzig, Germany; and Warsaw, Poland) during the ACTRIS (Aerosol, Clouds and Trace Gases Research Infrastructure) COVID-19 campaign in May 2020. The reanalysis (fully quality-assured) lidar data products, after the centralized and automatic data processing with the Single Calculus Chain (SCC), were used in this study, focusing on particle backscatter coefficients at 355 and 532 nm and particle linear depolarization ratios (PDRs) at 532 nm. A novel method for the characterization of the pure pollen depolarization ratio was presented, based on the non-linear least square regression fitting using lidar-derived backscatter-related Ångström exponents (BAEs) and PDRs. Under the assumption that the BAE between 355 and 532 nm should be zero (±0.5) for pure pollen, the pollen depolarization ratios were estimated: for Kuopio and Warsaw stations, the pollen depolarization ratios at 532 nm were of 0.24 (0.19–0.28) during the birch-dominant pollen periods, whereas for Hohenpeißenberg and Leipzig stations, the pollen depolarization ratios of 0.21 (0.15–0.27) and 0.20 (0.15–0.25) were observed for periods of mixture of birch and grass pollen. The method was also applied for the aerosol classification, using two case examples from the campaign periods; the different pollen types (or pollen mixtures) were identified at Warsaw station, and dust and pollen were classified at Hohenpeißenberg station.

Распределение влаги по сечению ствола дерева в ельниках черничных

The article considers the change in the moisture content in the wood along the cross-section of spruce trunks, it also analyzes the influence of the trees age and the diameter of the trunk on the wood moisture content. The research was carried out in the Arkhangelsk Forestry in the bilberry spruce forests of different age classes (from IV to VIII). 10 trial plots were laid in clear stands or with a small mixture of birch and pine. To study the moisture content of spruce trunks, 15 sample trees (150 in total) were selected for each trial plot. The wood moisture content was determined on cores sequentially divided into 5-millimeter segments. Wood samples were weighed on a VT-500 torsion balance and dried in a drying cabinet at a temperature of 105 °C to a completely dry state. The relative moisture of wood was calculated. As a result of the conducted studies, the moisture of sapwood (from 44,8 to 45,9 %) and heartwood (from 32,2 to 36,1 %) was established. Two models of changes in the amount of water at different distances from the cambium were identified. The majority of trees (78–98 %) are characterized by a well-defined water supply zone, the moisture content of which is maximum at a distance of up to 25 mm from the cambium, after which it decreases sharply. The water supply zone is represented by approximately 40...50 outer annual rings. The second model is characterized by a gradual decrease in wood moisture along the radius from the periphery to the center of the trunk. Such a model of changes in the moisture content of wood in the cross-section of the trunk is rare, mainly in young trees. As the trunk diameter increases, the moisture content of sapwood decreases. There was no significant difference in the sapwood moisture of spruce trunks of different age classes. The sapwood moisture decreases from the root neck to 1.5 m in height of the trunk, varying from 52...53 % to 49,0...49,5 %.

Alternative Feedstock for Producing Nitrocellulose

Tendencies toward growth in the demand for nitrocellulose in most developed countries and an expansion of applications owing to the creation of safe production technologies are observed. Nitration of cellulose from deciduous tree species, i.e., a 60:40% mixture of birch and aspen, is investigated. The structure of the nitration product is determined using IR and Raman spectroscopy. Cellulose nitrate characterized by a nitrogen mass fraction >10% is obtained for the optimal nitration parameters.

Stand age and climate influence forest ecosystem service delivery and multifunctionality

We examine how levels of multiple ecosystem services (ESs) change with succession in forests with different tree species composition. More specifically we ask how ecosystem age interacts with environmental conditions to regulate ES delivery. Using the nationwide Swedish forest inventory, comprising boreal and temperate regions, we investigated how levels of six provisioning, regulating, recreational, and/or cultural forest ESs changed with forest age (10–185 years) in stands of different tree species composition. We also tested whether the number of ESs delivered (i.e. multifunctionality) changed substantially with stand age, using different threshold levels for ES delivery. Accounting for environmental conditions and stand properties, we found that levels of single ESs changed with stand age. Tree biomass production usually peaked in young to medium aged stands. In contrast, production of berries and game, and services related to biodiversity, were typically highest in old stands (120–185 years). Consistent with this strong temporal tradeoff, multifunctionality at lower threshold levels increased with stand age in most monocultures and mixtures, with the highest multifunctionality being reached somewhere between 100 and 185 years, depending on tree species composition. This was not evident for the highest threshold ES level (the top-20%), however. Moreover, multifunctionality usually decreased with warmer climatic conditions, with the exception of spruce–pine–birch mixtures. Taken together, our results show that a reduced forest age, e.g. due to forestry targeting early harvest of stands, most likely would limit the delivery of several ESs valued by society and result in less multifunctional forests. To maintain the capacity of forests to deliver high levels of multiple ESs, the role of stand age and tree species composition should be considered in decisions on how to manage future forests.

Direct seeding of birch, rowan and alder can be a viable technique for the restoration of upland native woodland in the UK

An experiment was established to investigate techniques for improving the reliability of direct seeding for the conversion of commercial conifer forests to native woodland. After 7 years, despite the presence of seed eating predators on site, an equivalent of between 9000 and 12 000 seedlings per hectare, depending on the initial sowing rate used, comprising a mixture of birch (Betula pubescens Ehrh.), rowan (Sorbus aucuparia L.) and alder (Alnus glutinosa (L.) Gaertn.), had established in the cultivated treatments. Seed pre-treatment and sowing date had little impact on seedling numbers, but cultivation was beneficial. Very few seedlings occurred naturally in the unsown control plots. Our work suggests direct seeding may be a viable technique for converting some less fertile, freely drained, upland restock sites to a woodland consisting of birch, alder and rowan, but only if an appropriate silvicultural regime is put in place. Sowing can be combined, on the same restock site, with enrichment planting of other native species with more expensive seed such as indigenous Scots pine (Pinus sylvestris L.), oak (Quercus petraea Matt. (Liebl.); (Quercus robur L.)) and juniper (Juniper communis L.), which may also increase resilience to extreme climatic events in the first year after seeding.

Suppression of forest fuel thermolysis by water mist

The processes involved in the suppression of thermolysis in typical forest fuel (mixtures of birch leaves, asp branches, spruce needles) have been experimentally researched. The suppression was achieved by exposing forest fuel (FF) to water mist with different drop sizes. The drop radius was adjusted in the range between 50 µm and 500 µm. The spray intensity ranged from 0.01 to 0.065 l/(m2 s). The experiments were performed on a simulated fire source: an ad-hoc cuvette (100 mm in diameter, initial sample thickness 60 mm) where the FF sample was placed. The times necessary for complete FF combustion and the times necessary for suppressing the thermolysis of FF with water mist have been determined. It has been shown that the times of FF thermolysis suppression with fine aerosol are significantly shorter as compared to using a large-drop flow with the density identical to that of fine mist. The dependences between the water evaporation area in the combustion zone and the typical sizes of injected drops at identical spray density have been determined. The relation of energy spent on water evaporation and the heat accumulated in the combustion zone has been determined. The physical principles of a more efficient use of fine water mist for suppressing FF thermolysis (at constant spray density) have been determined. The conditions have been determined, under which a large-droplet mist can be used efficiently in gas-vapor-drop fire suppression technologies.

Species and soil effects on overyielding of tree species mixtures in the Netherlands

A growing number of studies provides evidence that mixed-species forests often have higher stand productivity than monospecific forests, which is referred to as overyielding. In this study, we explored how the combination of species and soil conditions affect overyielding in terms of periodic annual volume increment (PAIV) in Dutch forests. We studied Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), common beech (Fagus sylvatica L.), Scots pine (Pinus sylvestris L.), pedunculate oak (Quercus robur L.), and silver birch (Betula pendula Roth) growing in four two species combinations (Douglas-fir–common beech, Scots pine–pedunculate oak, pedunculate oak–common beech, and pedunculate oak–silver birch) from 398 long-term permanent field plots all over the Netherlands. We found that the Douglas-fir–common beech and Scots pine–pedunculate oak mixtures always showed overyielding. This overyielding was largely attributed to the Douglas-fir in the former mixture and to the pedunculate oak in the latter mixture, respectively. In both cases, overyielding was stronger at poor soils than at rich soils. The pedunculate oak–common beech mixtures overyielded at poor soils and underyielded at rich soils, which was attributed to the response of the common beech. Overyielding was not observed for the pedunculate oak–silver birch mixtures, irrespective of soil conditions. The results do not support our hypothesis since overyielding was not always driven by fast-growing light-demanding species. Overyielding was stronger for evergreen–deciduous species combinations, suggesting that differences in leaf phenology are a major driver of overyielding. Secondly, our results imply that overyielding is much stronger at poor soils than at rich soils, which is in line with the prediction of the stress-gradient hypothesis. We conclude that the growth of one species benefits from the admixture species, particularly in evergreen–deciduous species mixtures and that soils affect the extent of overyielding as studied in the Netherlands.

Study on the pyrolysis products of two different hardwood lignins in the presence of NiO contained-zeolites

Several NiO contained-zeolites (NiO/H-ZSM-5, NiO/H-BETA and NiO/H-Y) prepared by a mechanochemical dry milling (MCDM) were tested in the pyrolysis of two hardwood lignins: Eucalyptus (EUC) and a mixture of birch and aspen woods (BA). All prepared catalysts increased the yield of aromatics and decreased the yield of oxygenates as compared to non-catalytic experiment. The catalytic activity depends on the lignin type and zeolite structural features. The highest liquid and gas yields and lowest coke yield was obtained with NiO/H-Y which also increased the amounts of desirable and decreased undesirable pyrolysis products, giving a high concentration of hydrogen in the gaseous phase. The highest yield of aromatics and the lowest yield of oxygenates was obtained with NiO/H-ZSM-5. The obtained results showed that BA is a more suitable feedstock, producing higher yields of liquids and aromatics and lower yields of coke and oxygenates.

Physics of suppression of thermal decomposition of forest fuel using surface water film

The paper presents results of an experimental study of the suppression of thermal decomposition of forest fuel (FF) due to formation of a thin surface water film (3 mm thick). The investigations were carried out with birch leaves, as well as a mixture of birch leaves, pine needles, and twigs of aspen. The experiments involved model bases of fire of the above FFs in the form of cylinders. The cylinders were 20 mm to 60 mm in diameter and 40 mm to 100 mm high. The effect of water on the FFs was monitored via high-speed (up to 105 frames per second) video recording and fast (a thermal lag of less than 1 s) thermal transducers. The times of termination of FF thermal decomposition and the minimum (required) volumes of water were determined. The feasibility of complete suppression of the FF thermal decomposition process due to formation of a thin surface water film (10–15 times thicker than the reacted material) was experimentally supported. The foundations of the physical model of a complex of processes that occur owing to the water film effect on the forest fuel heated to a high temperature (well above the point of thermal decomposition) were formulated.

Pyrolysis of lignin with 2DGC quantification of lignin oil: Effect of lignin type, process temperature and ZSM-5 in situ upgrading

Thermal and catalytic pyrolysis of various types of lignin and their influence on the yield and the quality of the produced lignin oil were studied. Lignins originated from a mixture of pine and spruce wood (softwood), a mixture of birch and aspen wood (hardwood) and Eucalyptus Urograndis. High degree of deoxygenation of the bio-oil and maximum yield of value-added chemicals were the main targets of this work. 2DGC-ToFMS analysis was used for the qualitative and quantitative characterization of the lignin oils. Softwood lignin was found to be the most attractive feedstock and high yields of a mixture of phenolic compounds were detected in all cases. High char production was also evident for all types of lignins accounting for almost 50% of the original feedstock. The use of a commercial ZSM-5 catalyst was extremely beneficial for the process, enhancing deoxygenation at higher oil yields compared to thermal pyrolysis. Depending on the nature of the lignin, guaiacyl or syringyl groups were dominant in the oils and it was found that process optimization, involving lignin, catalyst selection and temperature could significantly improve the process efficiency.

Soil Chemical and Microbial Properties in a Mixed Stand of Spruce and Birch in the Ore Mountains (Germany)—A Case Study

A major argument for incorporating deciduous tree species in coniferous forest stands is their role in the amelioration and stabilisation of biogeochemical cycles. Current forest management strategies in central Europe aim to increase the area of mixed stands. In order to formulate statements about the ecological effects of mixtures, studies at the stand level are necessary. In a mixed stand of Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth) in the Ore Mountains (Saxony, Germany), the effects of these two tree species on chemical and microbial parameters in the topsoil were studied at one site in the form of a case study. Samples were taken from the O layer and A horizon in areas of the stand influenced by either birch, spruce or a mixture of birch and spruce. The microbial biomass, basal respiration, metabolic quotient, pH-value and the C and N contents and stocks were analysed in the horizons Of, Oh and A. Significantly higher contents of microbial N were observed in the Of and Oh horizons in the birch and in the spruce-birch strata than in the stratum containing only spruce. The same was found with respect to pH-values in the Of horizon and basal respiration in the Oh horizon. Compared to the spruce stratum, in the birch and spruce-birch strata, significantly lower values were found for the contents of organic C and total N in the A horizon. The findings of the case study indicated that single birch trees have significant effects on the chemical and microbial topsoil properties in spruce-dominated stands. Therefore, the admixture of birch in spruce stands may distinctly affect nutrient cycling and may also be relevant for soil carbon sequestration. Further studies of these functional aspects are recommended.

Biomass production of coppiced grey alder and the effect of fertilization

We studied biomass production of two naturally originated grey alder ( (L.) Moench) stands having a mixture of birch and willow located in central Finland. One of the stands was growing on a peatland site (Muhos) and the other on a mineral soil site (Juuka). The stands were clear-cut and fertilization experiments were laid out with several treatments. At Muhos, the treatments included nitrogen fertilisation with different amounts of wood ash and an unfertilized control. At Juuka, the treatments included nitrogen fertilisation either with ash or with PK, and ash and PK treatments alone and an unfertilized control. The sprouts at Muhos were grown for 17 years and at Juuka for 20 years. At Juuka the stand was clear-cut second time at the age of 20 years and grown for 8 years. The stands were measured several times and foliar samples were taken twice during the study period. Clear-cutting increased stem number manifold. The stand density of new coppiced forests after the clear-cutting decreased from 67 000–89 000 stems ha at the age of 3–6 years to 10 000–12 000 stems ha at the age of 17–20 years. On neither site fertilization affected biomass production of alders during the study period. Leafless above-ground biomass was 52–57 Mg ha after 17–20 years. Mean annual leafless above-ground biomass production (MAI) increased with increase of rotation time. At the age of 17–20 years the MAI was 2.8–3.0 Mg ha a. At Muhos, ash increased foliar P and Ca concentrations, but decreased those of Mn.Alnus incana–1–1–1–1

基于生物多样性保护的兴安落叶松与白桦最佳混交比例——以阿尔山林区为例

To find the optimum mixture ratio of larch(Larix gmelinii) and birch(Betula platyphylla),seven forest types were set in Inner Mongolia,including pure larch stand,pure birch stand,and five mixed stands with various tree proportions.Each forest type had three stands as replicates.Species richness and diversity of plant and insect populations were investigated and analyzed by traditional community investigation and manual collection.For the plant community,88 species were recorded and the dominant communities included Compositae,Rosaceae,Ranunculaceae,Papilionaceae,Ericaceae and Pinaceae.The dominant populations were Carex chingannensis Litw.,Lolium perenne L.,Fragaria orientalis Lozinsk.,Equisetum palustre L.,Geranium dahuricum DC.,Galium boreale L.while the rare populations included Heracleum moelledorffi,Ligularia fischeri,Pedicularis rubens and Viola acuminate.For the insect community,147 species were recorded.Lymantria dispar L.,Loxostege sticticalis L.,Chilo suppressalis(walker),Sidemia spilogramma Rambur,Chrysomelidae,Muscidae,Staphylinidae,Eusilpha sp.,Nitidulidae,Ips subelongatus Motschulsky were found as the dominant populations while Tomicobia seitneri(Ruschka)and Sipyloides sipylus were classified as rare speices.As the birch mixture in mixed forests increased,the species richness of plant and arthropod first increased and then decreased and peaked in L70B30 forests.The diversity of them had similar pattern as species richness.The distribution status of plant and insect populations along the gradient of birch mixture was also examined by the application of canonical correspondence analysis(CCA).The explaining environmental factors included mixture proportion(quantified by the mixture of birch),canopy closure,stand slope and soil organic matter(%).The results showed that the distribution of plant communities was well reflected by the CCA analysis.34.1% and 37% of the plant-environment relation was explained by axis 1 and 2,respectively.Birch mixture(BM) had significantly negative correlation with axis 1 while the canopy closure(CC) had a significantly positive correlation.In terms of the insect diversity,axis 1 and 2 explained 34.8% and 28.1% of the insect-environment relation while BM and CC also had similar correlations with axis 1 and 2.The results showed that most populations were significantly affected by the mixture status and canopy closure,which was also significantly decided by the composition status of canopy layer.In addition,the stand slope can also change their distribution status.These results also indicated that the diversity of plants and insects was highest when the mixture ratio of larch and birch was between 5 ∶ 5 and 7 ∶ 3,which should be the optimum mixture ratio in thinning practices.The present study is to provide theoretical base to improve the forest management,including how to quantify and control the thinning intensity.Generally,the relation of diversity and forest ecosystem stability was considered as positive which meant that the stability will increase with the diversity level.Therefore,the present study provides a new way to improve the health level of boreal forests in northeastern China.The forest manager could carry out various practices to transform the simple structure of forests,especially for the man-made forests and to keep and increase the forest health in this area.

Plant and insect diversity along an experimental gradient of larch-birch mixtures in Chinese boreal forests

Maintaining and increasing biodiversity level especially in pure plantations is one important way to improve the resistance of forests to pests in Chinese boreal forests. The present study tested the hypothesis that the increased degree of tree species mixture (quantified by the stem proportion of Betula platyphylla Suk. and Larix gmelinii (Rupr.) Rupr.) can affect the species richness and diversity of understory and insects. Twenty-one plots, ranging from pure larch stand to pure birch stand, were sampled in several thinned forests in a Chinese boreal forest area. Data of environmental factors, understory plant species and insect assemblage were collected from the field and connected with historical records, and analyzed using, e.g., multivariate methods and de-trended canonical correspondence analysis (DCCA). The results showed that the variation of plant and insect species was mainly influenced by birch mixture and light conditions in the forest. Species richness and diversity of plants and insects increased with the increasing mixture of birch, and finally declined after passing the peak point in 30% or 50% of birch mixture. The study gives tools to improve the integrated pest management (IPM) especially in man-made pure plantations of boreal forests in China.

Development of single-storied mixtures of Norway spruce and birch in Southern Sweden

In a stand with planted Norway spruce (Picea abies (L.) Karst.) and naturally regenerated birch (Betula pendula Roth and B. pubescens Ehrh.) in southern Sweden, the proportion of birch was reduced in 0.1-ha plots at pre-commercial thinning to 0%, 20% or 50% of the total stem number (2000–2500 stems ha−1 after the thinning). The growth of both species was surveyed 4 and 10 years later. No significant between-treatment differences were observed on either occasion in total yield or in spruce diameter (apart from a more negative skewness of the diameter distribution of Norway spruce in the mixture with 50% birch compared to pure spruce). Birch retained its initial advantage in dominant height (of about 2 m) throughout the 10-year measurement period; hence, height growth rates of Norway spruce and birch were very similar. After three, four and 10 growing seasons, whipping damage to Norway spruce caused by birch was registered in the 20% and 50% birch mixtures, in which the proportions of damaged spruces were found to be similar, with 17% and 15% of damaged trees at the last inventory, respectively. In addition, simulations of the stands’ development from the time of the last measurement until final felling at a total age of 66 years indicated that growth, yield and net present value decrease with increasing birch proportion, but if the proportion of birch removed in subsequent thinnings is increased, the between-treatment differences are reduced.

Clinical outcome and IL‐17, IL‐23, IL‐27 and FOXP3 expression in peripheral blood mononuclear cells of pollen‐allergic children during sublingual immunotherapy

Induction of allergen-specific, tolerogenic, IL-10 and/or TGF-β-producing T-regulatory (Treg) cells that express transcription factor FOXP3 is considered as one of the key mechanisms of allergen-specific immunotherapy. However, little is known of the induction of FOXP3 expression in children during sublingual immunotherapy (SLIT). Recently, also, a novel subgroup of T-helper (Th) cells, the Th17 cells, secreting predominantly IL-17 (IL-17A), was identified. The expressions of IL-17 or the Th17-regulating cytokines IL-23 and IL-27 during SLIT are currently completely unexplored. This randomized, placebo-controlled dose-response study was performed to analyze the effects of SLIT on FOXP3, IL-17, IL-23, and IL-27 expressions in peripheral blood mononuclear cells (PBMC) of children with allergic rhinitis and their associations with clinical outcome. Thirty children were included: ten received SLIT with a glycerinated mixture of birch, hazel and alder with a cumulative weekly dose of 24,000 SQ-U, 10 with dose 200,000 SQ-U/wk, and ten received placebo. Cytokine and FOXP3 mRNA expressions in allergen-, purified protein derivative-stimulated and non-stimulated PBMC were determined at 0, 1 and 2 yr of SLIT by real-time RT-PCR (TaqMan). Symptoms and medications were recorded using diary cards. Allergen-induced IL-17 mRNA expression was significantly increased in the study subjects with elevated combined Symptom Medication Score (SMS) after 2 yr. There was also a significant positive correlation between the allergen-induced IL-17 and SMS in whole study group (r = 0.38, p = 0.039) and especially the 200,000 SQ-U dose-treated group (r = 0.74, p = 0.027) at 2 yr. Allergen-induced FOXP3 mRNA expression was significantly increased in the 200,000 SQ-U dose-treated children after two study years as compared with baseline (p = 0.016) and placebo-treated children (p = 0.028). The changes in FOXP3 mRNA expression positively correlated with IL-10 and TGF-β mRNAs during SLIT in whole study population. Increased allergen-induced IL-17 responses during SLIT are associated with elevated SMS. Increased tolerogenic, allergen-specific Treg responses are also observed in children during SLIT.

Productivity of aspen forests in northeastern Minnesota, U.S.A., as related to stand composition and canopy structure

Relationships among stand composition, stemwood productivity, and canopy structure were investigated for 55 study areas in northeastern Minnesota. Tree species composition among study areas was deliberately allowed to vary. Aspen, primarily quaking (Populus tremuloides Michx.) and to a lesser degree bigtooth (Populus grandidentata Michx.), was a significant component of every study area. The two most common associates were paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill.). Productivity was defined as mean annual increment of tree stemwood volume and ranged from 3.3 to 12.6 m3·ha–1·year–1. A multiple-regression approach was used to investigate the relationships between productivity, stand composition, and canopy structure. Base models relating productivity to aspen site index, aspen cohort age, and total basal area were developed. Measures of stand composition and canopy vertical structure were added to the base models, and their significance in explaining residual variation in productivity was tested. Productivity was found to be negatively correlated with stand composition and canopy vertical structure, with all other factors held constant. Pure aspen and single-canopied stands were expected to be the most productive. Exceptions were present in the data: the two most productive stands were vertically stratified, aspen – balsam fir – paper birch mixtures.

Effect of tree stand and site variables on alpha diversity of ground vegetation in the forests of Northern Karelia

Generalised linear models (GLMs) were used to estimate the alpha diversity of the ground vegetation of boreal managed forests. Alpha diversity was described using Simpson's reciprocal, which was employed as a response variable in modelling, the explanatory variables being the tree and site characteristics. The data were from Northern Karelia, Eastern Finland. Several combinations of error and link functions were used to examine the patterns in the data, the best results being obtained with a model containing the normal error and identity link function, and the second power of the explanatory variable and one containing the gamma error and reciprocal link function. Site type, the presence of pubescent birch and the basal area of the stand were the significant variables in these models.It was concluded that GLMs are suitable tools for estimating biodiversity within the scope of the present data. In addition, it was found that the highest ground vegetation diversity exists within fertile stands with a mixture of birch and a low stand basal area. Models of this kind would be useful in forest management planning in order to study the effect of management on vegetational diversity using the values of different tree stand and site variables before and after treatment.