Patterns of tree growth in a single tree selection silver fir–European beech forest

The basal area and height growth of trees and saplings in silver fir–European beech single stem selection forest were studied with regard to their social status and crown parameters of size, coverage, shading and vitality. On 24 permanent research plots (20 m × 20 m each) all trees [diameter at breast height (dbh) ≥10 cm] and saplings (≥1.3 m tall and dbh <10 cm) were surveyed. Repeated measurements of dbh (N = 1,608) and height (N = 1,135) 10 years apart enabled the calculation of annual basal area increment (BAI) of trees and saplings, and annual height (HI) increment of saplings. To obtain the growth characteristics for individual trees and saplings, their social status and crown parameters were assessed by rank. In the multivariate general linear model for BAI, social status, crown size and crown coverage of individuals as the predictors, and dbh² as the covariate, explained 70% of total variability. Similarly, social status, crown size, crown coverage and crown shading had a significant impact on the HI of saplings, explaining 70% of total variability. Among the observed variables, social status determined according to the individual’s position in vertical stand structure was, in addition to dbh, the most important predictor for both BAI and HI. Significant differences were observed between the BAI and HI models for the main tree species (European beech and silver fir), indicating their different growth characteristics. The applied method could be used as a supplement to the more widely used approaches for studying basal area and height growth of individual trees in selection forest stands.     

Long-term changes of structure and tree species composition in Dinaric uneven-aged forests: are red deer an important factor?

Uneven-aged silver fir-European beech forest stands were studied to (1) analyse the dynamics of diameter structure and tree species composition in the past two centuries and (2) determine the impact of red deer on the regeneration and recruitment of silver fir. The study used current data on forest stands, archival data from old forest management plans for the period 1789–2004, and red deer harvesting records for the period 1907–2006. During the observation period, the silver fir population aged and silver fir and European beech alternated in dominance. The study revealed a strong impact of red deer on the composition and recruitment of tree regeneration, especially on silver fir regeneration. The drastic changes in red deer density (from extermination up to 5.8 animals km⁻²) and past forest management practices were apparently the main factors driving the population dynamics of silver fir (regeneration, recruitment, and diameter structure) in the study area during the past two centuries.     

Recruitment of tree species in mixed selection and irregular shelterwood forest stands

Context

Recruitment is an important process in forest stand dynamics, especially in uneven-aged stands. Continuous recruitment is a prerequisite for diverse, uneven-aged silvicultural systems, but patterns may vary significantly.

Aims

The main goals of the study were to examine the recruitment of the main tree species in selection and irregular shelterwood stands in silver fir?CEuropean beech?CNorway spruce forests and to determine the main predictors of the recruitment occurrence.

Methods

Data from 5,486 permanent inventory plots were used to study recruitment of saplings into the tree layer (diameter at breast height ??10?cm).

Results

Recruitment rate differed significantly between selection (7.6?trees?ha^?1?year^?1) and irregular shelterwood (26.1?trees?ha^?1?year^?1) stands. Shade-tolerant fir and beech recruited with higher probability in selection stands, while light-dependent sycamore recruited with higher probability in irregular stands. In addition, forest types, soil pH, stand basal area, mean diameter, and the basal area of the same tree species with respect to recruitment were found to be important predictors of recruitment occurrence.

Conclusions

The application of different uneven-aged silvicultural systems and their forms makes it possible to considerably influence the future tree species composition of uneven-aged forests.     

The effects of sage extract feed supplementation on biochemical parameters, weight of internal organs and Salmonella counts in chickens

We investigated the effects of dietary addition of sage extract on the biochemical parameters, weight of some body organs and changes in the counts of Salmonella Enteritidis PT4 (SE) in experimentally infected chickens. The following diets were used: basal diet, basal diet with addition of an extract of Salvia officinalis L. (S), basal diet and SE, and basal diet and S and SE (SSE). Compared to the SE group, sage extract in the SSE group decreased activities of ALP and ALT and concentrations of glucose and bilirubin on the 4th day post inoculation (p.i.). However, on the 18th day p.i., lower levels of bilirubin and ALT activity only were detected. Addition of sage extract to the diets decreased the counts of Salmonella in the liver, spleen and caecum at both sampling times, along with lower production of mucus in the chickens' intestines. Our results suggest that the addition of sage extract to the diet could be effective in protecting SE-infected chickens.     

The influence of omega-3 polyunsaturated fatty acids (omega-3 pufa) on lactobacilli adhesion to the intestinal mucosa and on immunity in gnotobiotic piglets

The effect of application of omega-3 polyunsaturated fatty acids (omega-3 PUFA) on intestinal colonization by Lactobacillus paracasei and on cellular immunity has been investigated in gnotobiotic pigs. The administration of polyunsaturated fatty acids positively affected the adhesion of Lactobacillus paracasei to the jejunal mucosa of gnotobiotic piglets. When compared to the control group, the number of Lactobacillus paracasei adhering to the jejunal mucosa was by 12% higher in piglets of the experimental group (5.10 log 10/cm2 vs. 4.55 log 10/cm2). The respective counts of Lactobacillus paracasei adhering to the ileal and colonic mucosa of 28 day old gnotobiotic piglets reached 4.45 and 5.05 log 10/cm2 in group C and 4.44 and 4.95 log 10/cm2 in group E. Omega-3 PUFA supplementation increased the phagocytic activity of neutrophils by almost 100% on day 28 of life as well as the subpopulations of lymphocytes (CD8) in the peripheral blood of germ-free piglets on day 21 of life. Our results indicate that the action of probiotics in the gut may be modulated by dietary PUFA. The stimulatory effect of PUFA upon adhesion of lactobacilli could be used for enhancing the effectiveness of probiotics in inhibiting digestive tract pathogens.     

Invasive and quarantine pests in forests in Slovakia1

Biological invasions of insects, plants, and fungal pest species often cause substantial disturbance to forest ecosystems and as well as severe socioeconomic impacts. Central Europe acts as a ‘bridge’ between Western and Eastern Europe both ecologically and as an important transit corridor for people. Human activity, including the movement of material goods, increases the risk of invasions. Some species introduced in the past have been established, becoming common and causing serious problems (such as Dreyfusia nordmannianae or Hyphantria cunea). The status, importance and spatial distribution in Slovakia of seven different forest pests recently introduced into Slovak forest ecosystems (Cameraria ohridella, Coleotechnites piceaella, Cryphonectria parasitica, Dothistroma septospora, Ips duplicatus, Parectopa robiniella, Phyllonorycter robiniellus) as well as two others not yet recorded in Slovakia (Anoplophora glabripennis, Phytophthora spp.) is discussed.     

Effects of selective thinning on growth and development of beech (Fagus sylvatica L.) forest stands in south-eastern Slovenia

We studied the effects of two types of selective thinning on beech stands formed by a shelterwood cut in 1910 — with lower number of crop trees and higher thinning intensity (T1) and higher number of crop trees with lower thinning intensity (T2). The stands were thinned in 1980, 1991 and 2001. Despite a lower stand density after thinning, the annual basal area increments of thinned stands in both thinning periods (1980–1991 and 1991–2002) were around 20% higher compared to those of the control (unthinned) stands. The mean annual basal area increment of dominant trees was 30–56% larger in the thinned plots compared to the control plots. Of 176 initial crop trees in the T1, 72% were chosen again during the last thinning. In the T2, 258 crop trees were chosen in the first thinning, and only 62% of these trees were chosen again during the last thinning. Only crown suppression and diameter classes of crop trees significantly influenced their basal area increment when diameter classes, crown size, crown suppression, and social status were tested. In the thinned stands, the dominant trees are more uniformly distributed if compared to the dominant trees in the control plots. Finally, the herbaceous cover and the species diversity were higher in the thinned plots.     

Pedosedimentary and climatic reconstruction of the last interglacial and early glacial loess–paleosol sequence in South Tadzhikistan

The thick loess–paleosol-sequences in Tadzhikistan, which indirectly record the environmental changes from the Upper Pliocene to the present-day, have been extensively described from a chronostratigraphical and archaeological point of view. The genesis of the soil-sedimentary complexes and their implications for palaeoenvironmental reconstruction in Tadzhikistan, however, have been considered only relatively recently [Bronger, A., Winter, R., Derevjanko, O., Aldag, S., 1993. Loess–paleosol sequences in Tadjikistan as a palaeoclimatic record of the Quaternary in Central Asia. Quaternary Proceedings 4, 69–81; Lomov, S.P., Tursina, T.V., Zhou, L.P., 1996. Magnetic susceptibility of soils: Micromorphology and possible reconstructions of climate. In: Soil micromorphology. Studies in Soil Diversity, Diagnostics, Dynamics, 10th International Working Meeting on Soil Micromorphology. Moscow, Russia, July 8–13, 1996, p. 145]. The pedocomplex of Last Interglacial and Early Glacial age (Oxygen Isotope Stage 5) in the Tagidjar and Darai Kalon sections near the town of Khovaling is represented by three major stages of soil formation. The soil characteristics have been micromorphologically analysed. The distinction between primary and secondary carbonates is of major importance to understand the soil forming processes. The relative distribution of needle fibre calcite (NFC), micritic infillings (M), hypocoatings (CHC), coarse calcitic grains (CCG) and calcified root cells (CRC) provides detailed insights into the environmental conditions prior, during and following pedogenesis. The abundance of coprolitic aggregates (CA) and pupal chambers gives a clear indication of the rate of biological activity which prevailed during the last two soil forming stages. Void pseudomorphs after gypsum crystals (gypsum pseudomorphs) are frequently observed beneath the Cca horizons of the paleosols. Using the present-day climate and soilscape as a reference base, the obtained pedosedimentary events detected in the Tadzhikistan sections provide a detailed palaeoenvironmental record. Indeed, glacial and interglacial climates and soils respond to contemporaneous climatic schemes and soil forming processes, which are still active in the region today. The amount and the seasonal variability of precipitation, mostly, are at the origin of the variable soils formed during glacial and interglacial ages.     

Dietary intake among under-, normal- and overweight 9- and 15-year-old Estonian and Swedish schoolchildren

OBJECTIVES: To determine the differences in macronutrient and food group contribution to total food and energy intakes between Estonian and Swedish under-, normal- and overweight schoolchildren, and to estimate the association between diet and body mass index (BMI). DESIGN: Cross-sectional comparison between Estonian and Swedish children and adolescents of different BMI groups. SETTING: Twenty-five schools from one region in Estonia and 42 in two regions of central Sweden. SUBJECTS: In total 2308 participants (1176 from Estonia and 1132 from Sweden), including 1141 children with a mean age of 9.6 +/- 0.5 years and 1167 adolescents with a mean age of 15.5 +/- 0.6 years. RESULTS: Overweight was more prevalent among younger girls in Sweden (17.0 vs. 8.9%) and underweight among girls of both age groups in Estonia (7.9 vs. 3.5% in younger and 10.5 vs. 5.1% in older age group of girls). Compared with that of normal- and underweight peers, the diet of overweight Estonian children contained more energy as fat (36.8 vs. 31.7%) but less as carbohydrates, and they consumed more milk and meat products. Absolute BMI of Estonian participants was associated positively with energy consumption from eggs and negatively with energy consumption from sweets and sugar. Swedish overweight adolescents tended to consume more energy from protein and milk products. Risk of being overweight was positively associated with total energy intake and energy from fish or meat products. In both countries the association of overweight and biological factors (pubertal maturation, parental BMI) was stronger than with diet. CONCLUSION: The finding that differences in dietary intake between under-, normal- and overweight schoolchildren are country-specific suggests that local dietary habits should be considered in intervention projects addressing overweight.