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21.
Thinning increases drought tolerance of European beech: a case study on two forested slopes on opposite sides of a valley 总被引：1，自引：1，他引：0
Daniela Diaconu Hans-Peter Kahle Heinrich Spiecker 《European Journal of Forest Research》2017,136(2):319-328
European beech (Fagus sylvatica L.) is one of the economically most important broadleaved tree species in Central Europe. However, beech shows high drought sensitivity and calls for profound research to test its ability to cope with limited water resources. Here, we investigated the drought tolerance of beech to the 2003 drought as influenced by Kraft class, aspect and thinning intensity. Annual basal area increment data of 126 sample trees from southwest Germany were used to assess the variability of drought tolerance indices, by comparing three social classes (predominant, dominant and co-dominant), two contrasting sites [a dry southwest (SW) aspect and a moist northeast (NE) aspect], and three treatments [control, strong thinning (stand basal area 15 m2 ha?1) and very strong thinning (stand basal area 10 m2 ha?1)] in mature beech stands. Our results show that the co-dominant and dominant trees had lower growth recovery and lower growth resilience after the drought, compared to the predominant trees. The differences between aspects pointed to a growth–drought tolerance trade-off, in which trees on the SW aspect displayed lower growth rates but higher resilience indices than trees on the moist NE aspect. Furthermore, our results suggest that the resistance to and resilience after the 2003 drought significantly increased for the thinned trees. Our results provide novel insights into the linkage between the forest stand management and drought tolerance of beech under contrasting sites. We conclude that thinning can partially alleviate effects of severe drought on European beech forests in southwest Germany and can be applied as an adaptive measure to increase the mitigation potential of beech stands. 相似文献
22.
Effect of dietary vitamin E and selenium supplementation on semen quality in Cairn Terriers with normospermia 
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下载免费PDF全文 Among others, selenium (Se) and vitamin E (VitE) have been provided to dogs to improve semen quality. However, scientific evidence documenting an effect in dogs is lacking. The aim of this study was to investigate the effect of supplementation of these antioxidants on various ejaculate parameters in a randomized, double‐blinded trial using Cairn Terrier males exhibiting normal seminal quality parameters. Three dogs each were fed a standardized diet and supplemented with 0.1 mg Se, 100 mg VitE or 0.1 mg Se + 100 mg VitE/dog for 3 months. Ejaculate analyses (volume, progressive motility, vitality, morphology, concentration) were performed before inclusion (D0) and after 1, 2 and 3 months (+1, +2, +3). At the same time, glutathione peroxidase (GSH‐PX) and VitE in seminal plasma (SP) and GSH‐PX in blood samples were determined. Vitamin E levels in SP were below the detection limit (1.0 mg/L) in all samples. GSH‐PX in blood (164.0–2794.4 IU/L) and SP (18.4–4326.0 IU/L) was highly variable. Supplementation only significantly affected the total percentage of sperm head abnormalities (p = .011). Time significantly affected the percentage of morphologically abnormal sperm (p = .025), sperm head abnormalities (p = .007), proximal droplets (p = .001) and GSH‐PX in SP (p = .015). Additionally, a significant interaction between time and group was identified for the percentage of membrane‐intact sperm (p = .048), head abnormalities (p = .018), acrosomal defects (p = .043) and proximal droplets (p = .002). Although some effects could be identified for selected parameters, we failed to identify a clear trend about how a 3 months VitE and/or Se supplementation affects semen parameters in normospermic Cairn Terriers. 相似文献
23.
Airborne laser scanner (ALS)-based forest inventory method usuallyadopt a laser canopy height distribution approach in which forestcharacteristics are predicted using measures such as percentilesof the distribution of laser canopy heights across a fixed area.The method requires a ground-truth sample of accurately measuredfield plots. One possibility for reducing the costs lies inthe use of existing field plots for ground-truth purposes. Themost obvious alternative in Finland would be to use truncatedangle count sample plots of the National Forest Inventory ormore locally data of checking of inventory by compartments.Due to the lack of suitable angle count ground-truth data andcorresponding laser data, we tested this possibility using dataon fixed-area sample plots, in which tree locations were simulated.The trees for a truncated angle count sample plot were thenchosen and the resulting data together with the characteristicsof an ALS-based canopy height distribution were used to constructregression models to predict stem volume, basal area, stem number,basal area median diameter and height. The accuracy of the standattributes was found to be almost as good as in the case ofmodels of fixed-area plots. 相似文献
24.
Human activity in the environment has great impact on soil ecology. However recent knowledge on properties of anthropogenic soils is still scarce. For this reason the purpose of this paper is to deliver data on the soil organic matter (SOM) properties of urban soils with an example from the city of Rostock (Northeast Germany) and to describe the environmental consequences of severe anthopogenic actvity. The results suggest that SOM of urban settings is significantly different in their chemical nature of humic compounds and their coal contents. The lower content of alkyl C and the simultaneously higher contents of aromatic C moieties in urban soils compared to their natural counterparts suggest a substantially different biochemical behavior against environmental hazardous compounds and microbial activity. This knowledge is essential for a qualitative assessment of important biochemical mechanisms in urban soils. 相似文献
25.
The commonly used multiple‐liner‐system of modern top sealings of contaminated sites is expensive and in many cases (minor hazardousness of pollutants), not necessary. As an alternative, we investigated the performance of willow stands as the only measure to reduce percolating soil water and therewith pollutant transport to underlying ground water resources. It is well accepted that willows have a high water demand and may considerably reduce percolation. On the basis of experimentally determined soil physical properties of a landfill site, we performed water balance calculations with the physically based HYDRUS‐code and a simple bucket approach. The 20 yr annual leachate rate for bare soil was calculated to vary from 336 (HYDRUS) to 451 mm yr—1 (bucket‐model). Willows were able to reduce the annual leachate to 146 (HYDRUS) and 186 mm yr—1 (bucket‐model), indicating their great performance compared to a grass‐ or beechwood cover. However, legal regulations (TASi) in Germany cannot be met with the proposed method. In minor hazardous cases, official authorities may accept willow stands as an alternative system for protection. 相似文献
26.
Karl Heinz Mellert Jörg Prietzel Ralf Straussberger Karl Eugen Rehfuess Hans Peter Kahle Pedro Perez Heinrich Spiecker 《European Journal of Forest Research》2008,127(6):507-524
Height growth of 19 Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) stands in Germany, Austria and Finland, for which long-term records of foliar nutrient levels were available, was assessed
retrospectively by stem analyses and compared with data from regionally applied yield tables as references. Gridded historical
time series of monthly temperature and precipitation were used to characterise the meteorologic conditions at the sampling
sites. Climate parameters were tested against height growth in period 1950–2000, and needle N content was tested against height
growth for the periods where N measurements were available by means of graphical comparison, as well as simple and multiple
regression analyses with the aim to get evidence for causes of possible growth acceleration. Trends of referenced height increment
of six out of nine Scots pine stands in Germany were positive during the observation period, and improved N nutrition appeared
to be the most important driving factor for this growth acceleration. The variation of precipitation—exhibiting no consistent
and uniform long-term temporal trend during the observation period—in contrast seems to be mainly responsible for the interannual
fluctuation of height growth. We were not able to detect any general statistical influence of temperature parameters on height
growth, although they generally increased. The referenced height growth of three Finnish pine stands slightly decreased during
the observation period and there was no indication of a significant improvement of their N supply. Among four Norway spruce
stands investigated in Germany and Austria, referenced height increment also increased in three cases; there was again some
evidence that improved N nutrition was the stimulating factor. At three study sites in Finland, however, referenced height
growth of this species decreased at least from 1985 onwards, whereas mostly no significant trends in N nutrition or precipitation
were identified. These differences observed between species and regions are discussed in detail. 相似文献
27.
Effect of organic matter content on the consistency of several mineral substrates The effect of organic matter content on the consistency of soils different in texture was investigated. The shifts of the values of the consistency limits towards higher moisture contents are explained by different organic matter contents. The consistency limits of plasticity and liquidity. were significantly dependent on the content of organic matter. 相似文献
28.
Effects of 10 years of Miscanthus cultivation on different properties of mineral soil in North-east Germany
The effects of 4–10 years of Miscanthus cultivation on different soil properties was investigated at Klein Markow (Mecklenburg-Pommerania, Germany) in variants with and without Miscanthus between 1994 and 2000. Soil containing Miscanthus showed higher concentrations of organic carbon (Corg ) (+0,29 %) and total nitrogen (Nt ) (+0,03 %) and consequently an increased storage of soil organic matter (SOM) (+15,5 t ha–1 ) as a result of high amounts of leaves, roots and rhizomes. With regard to concentrations of Corg , cation exchange capacity, porosity and water retention significantly increased, while the wet and bulk density decreased in Miscanthus variants. The concentration of Corg and storage of SOM were increased significantly during the experimental period of Miscanthus treatments. The mineralization of the organic soil compounds which developed was comparable with those of the SOM. The reintegration of the Miscanthus area into a crop rotation system was possible only after the last harvest in February and seed of winter rape in August of the same year. The application of Glyphosat and the later shading by rape stands led to failure of the Miscanthus cultivations. 相似文献
The effects of 4–10 years of Miscanthus cultivation on different soil properties was investigated at Klein Markow (Mecklenburg-Pommerania, Germany) in variants with and without Miscanthus between 1994 and 2000. Soil containing Miscanthus showed higher concentrations of organic carbon (C
29.
Jürgen Hagemeyer Henning Kahle Siegmar-W. Breckle Yoav Waisel 《Water, air, and soil pollution》1986,29(4):347-359
Most of the airborne Cd-polluted particles which eventually precipitate in forest regions remain on the surface of the tree leaves and do not penetrate into the plants' live tissues. Such pollutions can be removed from the leaves by cation exchange or can be washed off with water of low pH. Acid rains and acid soils have contributed very much to the solubilization of Cd and to its transformation into an available ionic form which is later absorbed by tree roots. 115mCd uptake by young beech trees (Fagus sylvatica L.) seems to be positively correlated with the concentrations of the applied solutions as well as with the duration of the exposure. Low environmental pH increases the rate of 115mCd uptake. High or low transpiration had no apparent effect on root absorption of Cd, but exposure of beech trees to a Cd(NO3)2 solution reduced their rates of transpiration after very few days of treatment. 相似文献
30.
Petra Kahle Barbara Boelcke Steffen Zacharias 《Archives of Agronomy and Soil Science》2013,59(3):163-174
In vorliegenden Beitrag werden für 4 verschiedene Standorte in Deutschland die Bodeneigenschaften unter 4‐ bis 6‐jährigen Miscanthusbeständen als Grundlage für ein komplex angelegtes Untersuchungsprogramm vorgestellt und diskutiert. Die Varianten “mit Miscanthus” zeichnen sich durch geringfügig erhöhte Humusgehalte gegenüber “ohne Miscanthus” aus, verbunden mit weitreichenden Auswirkungen auf andere relevante Bodenmerkmale. Erkennbar werden Beeinflussungen der Wasserretention, der Porosität und der Lagerungsdichte. 相似文献