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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. 相似文献
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Matija Klopcic Klemen Jerina Andrej Boncina 《European Journal of Forest Research》2010,129(3):277-288
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. 相似文献
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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. 相似文献5.
Novak R Bogovič Matijašić B Terčič D Cervek M Gorjanc G Holcman A Levart A Rogelj I 《Journal of animal physiology and animal nutrition》2011,95(4):424-433
The objective of this study was to evaluate effects of two commercially available probiotic additives, containing Bacillus spores, on carcass and meat characteristics, serum lipids and concentration of cecal volatile fatty acids of meat type chickens. Birds were fed regular corn-soy meal based feed (control), supplemented with additive A, containing 1.6 × 10(6) spores per gram of feed of Bacillus subtilis and Bacillus licheniformis (group A) or additive B, containing the same concentration of Bacillus cereus var. toyoi spores (group B). One hundred and twenty birds (20 per replicate) were slaughtered at the age of 55 days. Results showed that birds in group B had higher (p < 0.05) final body weight compared to birds from group A and higher carcass weights and yield percentages compared with control. Breasts and whole legs were also heavier in group B, compared to control, but not the yield. Group A had higher yield of wings and lower abdominal fat weight compared to group B (p< 0.05), but not compared with control. Total cholesterol was not affected by the dietary treatment, on contrary both probiotics elevated the LDL (p < 0.05) and lowered HDL cholesterol, thus unfavourably changed animal's blood serum cholesterol profile. Both probiotics influenced the cecal fermentation, which was observed as decrease in cecal concentrations of propionic, butyric, n-butyric and n-valeric acids, but the differences compared to control group were statistically significant for group A only. It was established that probiotic additive B was more effective regarding carcass and meat part weights than additive A, however the animals from group B also had more abdominal fat and their meat had significantly higher conductivity than control group, which is not considered as beneficial. 相似文献
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Strlic M Radovic T Kolar J Pihlar B 《Journal of agricultural and food chemistry》2002,50(22):6313-6317
The anti- and prooxidative properties of gallic acid in Fenton-type systems containing H(2)O(2) and Fe(III) were examined in pH 3-10 reaction media and at reaction temperatures of 20-50 degrees C. Although it is a free radical scavenger, gallic acid may exhibit prooxidative properties, as it promotes the production of hydroxyl radicals due to iron chelation. The overall effect is prooxidative if the ratio of the concentrations of gallic acid and Fe(III) in the reaction medium is smaller than 2. If the ratio is greater than 2, the overall effect of gallic acid presence is antioxidative due to free radical scavenging properties. The dependence of rates and of apparent activation energies of gallic acid consumption on pH in Fenton-type systems was also examined, and it is concluded that the rate-determining steps in acidic and alkaline media are different, the overall rate of gallic acid consumption being lowest at pH 7. 相似文献
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Cuk M 《Science (New York, N.Y.)》2007,318(5848):244
The origin of the Moon's nonnegligible orbital eccentricity of 0.053 has no theoretical explanation. Lunar laser ranging indicates that tides on Earth are currently increasing the Moon's eccentricity. However, ocean tides were likely much weaker during the first billion years, allowing lunar tides to damp any primordial lunar eccentricity very early on. During the tidally driven expansion of its orbit, the Moon must have been affected by two substantial resonances related to Jupiter and Venus, passage through which may have generated today's lunar eccentricity. 相似文献
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Mukhtar MS Carvunis AR Dreze M Epple P Steinbrenner J Moore J Tasan M Galli M Hao T Nishimura MT Pevzner SJ Donovan SE Ghamsari L Santhanam B Romero V Poulin MM Gebreab F Gutierrez BJ Tam S Monachello D Boxem M Harbort CJ McDonald N Gai L Chen H He Y;European Union Effectoromics Consortium Vandenhaute J Roth FP Hill DE Ecker JR Vidal M Beynon J Braun P Dangl JL 《Science (New York, N.Y.)》2011,333(6042):596-601
Plants generate effective responses to infection by recognizing both conserved and variable pathogen-encoded molecules. Pathogens deploy virulence effector proteins into host cells, where they interact physically with host proteins to modulate defense. We generated an interaction network of plant-pathogen effectors from two pathogens spanning the eukaryote-eubacteria divergence, three classes of Arabidopsis immune system proteins, and ~8000 other Arabidopsis proteins. We noted convergence of effectors onto highly interconnected host proteins and indirect, rather than direct, connections between effectors and plant immune receptors. We demonstrated plant immune system functions for 15 of 17 tested host proteins that interact with effectors from both pathogens. Thus, pathogens from different kingdoms deploy independently evolved virulence proteins that interact with a limited set of highly connected cellular hubs to facilitate their diverse life-cycle strategies. 相似文献
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Klopčič Matija Mina Marco Bugmann Harald Bončina Andrej 《European Journal of Forest Research》2017,136(5-6):1071-1090
European Journal of Forest Research - In the Dinaric Mountains, the future of silver fir and Norway spruce appears to be uncertain, especially given the threat of climate change to both species and... 相似文献
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