Die Verjüngung gemischter Bergwälder—Praktische Konsequenzen aus 10jähriger Untersuchungsarbeit     

R. Mosandl  H. El Kateb 《European Journal of Forest Research》1988,107(1):2-13

Zusammenfassung Seit zehn Jahren betreibt der Lel-irstuhl für Waldbau and Forsternrichtung der Universit?t M?nchen intensive Verjüngungsstudien auf 25 Dauerversuchsfl?chen im Bergmischwald der ostbayerischen Kalkalpen. Am Bei-spiel der Aufnahmedaten yon fünf ausgew?hlten Versuchsfl?chen werden grundlegende Prinzipien des Ver-jüngungsprozesses im Bergmischwald aufgezeigt and daraus praktische Konsequznzen abgeleitet. Alle am Autbau der Altbest?nde des Bergmischwaldes beteiligten Baumarten bilden bislang trotz d utli-cher Waldschadenssvmptome reichlich Samen von hochwertiger Qualit?t aus. Damit aus diesem Verjüngungspotential Naturverjüngung entstchen kann, müssen die en tsprechenden überschirmungsverh?ltnisse lurch den Altbestand gegeben sein. Für die Dichte, Baumartenztusammenset zung and H?henentwicklung der Naturverjüngungspflanzen ist n?mlich die Uberschirrnung von ganz ent-scheidender Bedeutung. In einem sehr dichten Altbestand, in derv der überschirmungsgrad fiber 75% liegt , haben Verjüngungspflanzen Schwierigkeiten, sick zu etablieren. Eine Ieichte Auflichtung auf einen über-schirmungsgrad von 60 (der dann gegeben ist, wenn die rich unter dem Schirm entwickelnde Bodenvege cation Bedeckungsgrade zwischen 20 and 3C einstellt) erm?glicht den Naturverjüngungsflanzen ein überleben. Diese Uberschirmung kann durch einen schwachen Schirmhieb (Entnahme von etwa einem Vier-tel der Grundtl?che eines geschlossenen Bestandes) erreicht werden. Diese Eingriffsst?rke dürfte auch unter den Gesichtspunkten der Stabilit?it and des Zuwachsverlustes dill Altbestand zu vertreten sein. Vor einer st?rkeren Auflichtung des Altbestandes müsses genügend Naturverjüingungspflanztn ant Bo den vorhanden sein. Nur so is[ gew?hrleistet, daβ these einen Vorsprung vor der Bodenvegatation bekom Men. Die Pflanzung ist immer dann, wenn sich Schwierrigkeiten mit der Naturverjüngung ergeben, ein geeigne-tes Mittel, um einen neuen Bergmischwald zu begründen. Derzeit ist für das Entstehen tines neuen Bergmischwaldes - sei es durch Naturverjüngung odor lurch Pflanzung - Zaunschutz erforderlich. Summary In 1976, a research project entitled ’Natural Regeneration of Mixed Mountain Forests ’ was etablished in the Calcareous Alps of eastern Bavaria, by the Chair of Silviculture and Forest Management of the University Of Munich. Over the past ten years, the multi-variate aspects of regenaration have bean intensively investigated on 25 permanent research plots. The data from 5 selected plats were extracted and processed. from these data, it will be possible to present some fundamental principles of natural regenaration processes. From these prin-ciples, it is hoped that some practical applications can be derived. The mature stands of mixed mountain forests are still able to produce high quantities and good quality of seed, although distinct symptoms of forest decline are present. In order to utilize this potential for natural regeneration, an adequate canopy density is necessary. Canopy density is the crucial factor which regulates the density, species composition and height development of regeneration. In a very heavily, stocked mature stand with a canopy density of over 75 establishment of regenerations is difficult. When canopy density is reduced to, for example, 60% (this percentage can be estimated from a ground vegetation covering approximately 20–30 of the soil), the naturally regenerated, plants have a better opportunity to survive. A 60% canopy density can be achieved by light shelterwood cutting (removal of approximately 25% of basal area of a closed stand). This type of cutting can maintain the stability and prevent increment loss of forest stands. It is important that regeneration is established before opening up the stand, only, then these plants are capable to compete with the other ground vegetation. Planting is always appropriate when natural regeneration fails. Fencing is necessary for undisturbed development of natural and artificial regeneration.

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Dieses Heft enth?lt waldbauliche Beitr?g zu den Forschungsschwerpunkten Bergwald, Waldschaden und Kiefer. Sie sind überwiegen als Vortr?ge auf der Hochschulwoche der Forstwissenschaftlichen Fakult?t München im Oktober 1987 gehalten worden. Ihre Autoren widmen sie Herrn Professor Dr. Peter Burschel zum 60. Geburtstag.

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Auf der Forstlichen Hochschulwoche 1987 in München gehaltener Vortrag.  相似文献   

Ecophysiological and genetic variation in seedling traits and in first-year field performance of eight <Emphasis Type="Italic">Acacia senegal</Emphasis> provenances in the Blue Nile,Sudan     

El Amin Yousif Raddad 《New Forests》2007,34(3):207-222

The genetic variation in seed weight, seed number per kg and seedling traits was compared among eight Acacia senegal provenances originating from the clay plain (east) and sand plains (west) of the gum belt in Sudan. The main objective of this study was to identify germplasm sources of A. senegal that have a good seed germination capacity and seedling traits suitable for reforestation in the clay-soil part of the dryland gum belt in the Blue Nile region in Sudan. A specific objective was to tentatively explore the adaptive strategy of A. senegal populations. Seventeen-week-old seedlings were planted in the field at spacing of 3 m × 3 m, giving 100 trees per plot and replication; within a randomized complete block design with four replications. The experimental site was in the clay plain region. Seed variables showed significant differences. Clay plain provenances showed considerable variation in seed weight and seed number. They had the smallest seed weight but the highest seed number, while the sand (western) provenances had the largest seed weight but lowest seed number. Seedling branch number, root length, root to shoot ratio and shoot dry weight differed significantly among the provenances 12 weeks after germination. Clay provenances had the highest branch number and shoot dry weight but the shortest roots and lowest root to shoot ratio. This was interpreted as showing better adaptation to the site in these local provenances in comparison to those originating from the western sandy soil regions. High positive correlations were observed between seedling variables, such as root nodule and branch numbers; this could be used for early selection. The variation was greater between provenance groups than within them, suggesting that especially selection among groups would yield genetic gain.  相似文献   

Effect of Mediterranean saltbush (Atriplex halimus) ensilaging with two developed enzyme cocktails on feed intake,nutrient digestibility and ruminal fermentation in sheep          下载免费PDF全文

Haidy Alsersy  Abdelfattah Z. M. Salem  Borhami E. Borhami  Jaime Olivares  Hany M. Gado  Maria D. Mariezcurrena  Mohamed H. Yacuot  Ahmed E. Kholif  Mounir El‐Adawy  Saul R. Hernandez 《Animal Science Journal》2015,86(1):51-58

The aim of this study was to assess the effects of feeding Atriplex halimus (AH) silage treated with two developed enzyme cocktails to sheep on feed intake, nutrient digestibility and ruminal fermentation. The AH silage was treated without or with 2 L of ZAD1^® or ZAD2^®/1000 kg with 5% molasses and ensiled for 30 days. Barley grain (300 g/head/day) was fed as an energy supplement once daily at 10.00 hours and AH silage with or without enzyme treatment was offered ad libitum to animals twice daily at 09.00 and 16.00 hours. Sheep were fed on four experimental forage diets comprised of AH silage and barley (D1), AH silage treated with ZAD1^® and barley (D2), AH silage treated with ZAD2^® and barley (D3) and AH silage treated with a combination of ZAD1^® and ZAD2^® (1:1) and barley (D4). Ensiling AH with enzymes reduced its contents of neutral detergent fiber and acid detergent fiber. The dry matter intake of AH of D2, D3 and D4 decreased (P < 0.001) as compared to D1. However, enzyme‐treated diets had greater total digestible nutrients intake (P < 0.001) as compared to D1. The nutrients digestibility for D2, D3 and D4 were higher than those for D1 (P < 0.001), and were higher for D3 as compared to both D2 and D4. Sheep fed on D3 had highest (P < 0.001) ruminal total volatile fatty acids concentration, ammonia nitrogen concentration and microbial protein yield. It could be concluded that AH silage treated with ZAD1^® or ZAD2^® improved digestibility and rumen fermentation in sheep.  相似文献   

Analysis of genomic mutation and immunohistochemistry of platelet‐derived growth factor receptors in canine vascular tumours          下载免费PDF全文

S. Abou Asa  T. Mori  K. Maruo  A. Khater  A. El‐sawak  E. Abd el‐Aziz  T. Yanai  H. Sakai 《Veterinary and comparative oncology》2015,13(3):237-245

We examined whether mutation of the platelet‐derived growth factor receptor protein tyrosine kinase (PDGFR)‐α and PDGFR‐β genes contributes to their overexpression in canine vascular tumours. Genomic sequences of trans‐ or juxtamembrane regions of PDGFR‐α and PDGFR‐β were analysed with immunohistochemical staining and polymerase chain reaction‐direct sequencing using DNA from paraffin‐embedded neoplastic tissues of 27 hemangiosarcomas (HSAs) and 20 hemangiomas (HAs). Immunohistochemically, 75% of the HA cases were positive for PDGFR‐α and almost most of the HA cases were negative for PDGFR‐β. Of the HSA cases, 55.6% were negative for PDGFR‐α and 63% were strongly positive for PDGFR‐β. Among the HA cases, 1 missense mutation was detected in PDGFR‐α exon 18 and 1 in PDGFR‐β exon 17. Two HSA cases had missense mutations in exon 14 and 1 in exon 17 of PDGFR‐β. Thus, genomic mutation of trans‐ or juxtamembrane regions of PDGFRs was not the main mechanism driving the activation of receptors in HSA and HA.  相似文献   

Seroprevalence and risk factors associated with Chlamydophila spp. infection in ewes in the northeast of Algeria     

Sana Hireche  Omar Bouaziz  Djahida Djenna  Sabrina Boussena  Rachida Aimeur  Rachid Kabouia  El Hacène Bererhi 《Tropical animal health and production》2014,46(2):467-473

A cross-sectional study was carried out to estimate prevalence of Chlamydophila spp. antibodies and to investigate risk factors associated with chlamydial infection in 552 ewes between March 2011 and January 2012 in the province of Constantine. Anti-Chlamydophila antibodies were detected using an indirect enzyme-linked immunosorbent assay kit in 24.5 % of examined sera. Of the herds, 70.4 % had at least one seropositive animal. A pretested structured questionnaire was administered in order to collect information on individual animal health and herd management practices. Chi-square analysis and multivariable logistic regression model were used to identify risk factors related to Chlamydophila seropositivity. Univariable analysis revealed 17 variables with p?<?0.25 that were offered to the multivariable logistic regression model which in turn identified 12–23 months age group (OR?=?5.903, 95 % CI (OR)?=?1.690; 20.618) and not using disinfectants (OR?=?2.099, 95 % CI (OR)?=?1.314; 8.065) as risk factors for Chlamydophila spp. seropositivity. Moreover, occurrence of stillbirth problem (OR?=?3.682, 95 % CI (OR)?=?1.825; 7.430) and 5–10 % mortality rate in young lambs (OR?=?2.584, 95 % CI (OR)?=?1.058; 6.310) were significantly associated with seropositivity to Chlamydophila spp. On the other hand, availability of veterinary service was identified as a protective factor (OR?=?0.161, 95 % CI (OR)?=?0.051; 0.511).  相似文献   

Antibiotic susceptibility of bacteria isolated from infections in cats and dogs throughout Europe (2002–2009)     

Stéphane Kroemer  Farid El Garch  Delphine Galland  Jean-Luc Petit  Frédérique Woehrle  Henri-Jean Boulouis 《Comparative immunology, microbiology and infectious diseases》2014

A monitoring program of the pre-treatment susceptibility of clinical isolates of bacteria from diseased dogs and cats was active between the years 2002 and 2009. Susceptibility of each isolated strain to a panel of nine antibiotics (amoxicillin/clavulanic acid, ampicillin, penicillin, clindamycin, doxycycline, enrofloxacin, marbofloxacin, trimethoprim and trimethoprim/sulfamethoxazole) was assessed. The Minimum Inhibitory Concentration (MIC) of marbofloxacin was also determined by a standardized microdilution technique following CLSI recommendations. In total, 1857 bacterial strains were collected throughout Europe from cases of otitis, respiratory, urinary and dermatological infections. Although bacterial susceptibility varied for each of the antibiotics within the panel, patterns of susceptibility were similar to those described in the literature for comparable time periods and geographical areas. With a clinical resistance varying from 0 to 14.48% against the isolated strains, marbofloxacin susceptibility was very high and remains an effective antibiotic for the treatment of otitis, urinary, respiratory and dermatological infections in companion animals.  相似文献   

Effect of short‐term supplementation with rumen‐protected fat during the late luteal phase on reproduction and metabolism of ewes     

N. M. Hashem  S. Z. El‐Zarkouny 《Journal of animal physiology and animal nutrition》2014,98(1):65-71

This study was designed to study the effect of short‐term supplementation with rumen‐protected fat during the late luteal phase on reproduction and metabolism of sheep during breeding season. Seventy‐six ewes (Rahmani, Barki and Awassi × Barki) were allocated to two groups considering genotype: the control ewes (C‐group) received a maintenance diet, and the fat‐supplemented ewes (F‐group) received the maintenance diet plus 50 g/head/day of rumen‐ protected fat (Megalac) for 9 days during which oestrus was synchronized. The latter had been accomplished using double intramuscular injection of prostaglandin F_2α (PGF_2α) 11 days apart. Ovarian activity, serum concentration of cholesterol, glucose, insulin and reproductive performance variables were recorded. Data were analysed considering treatment (group) and genotype. Supplementation had positive effects on the overall mean serum concentrations of cholesterol (p < 0.05), glucose (p < 0.05) on day 6 of nutritional treatment and insulin (p = 0.07) on day 8. Fat supplementation did not affect the total number of follicles, follicle populations and ovulation rate. However, fat‐supplemented Rahmani ewes tended to have higher ovulation rate compared with other breeds (treatment × breed interaction, p = 0.06). Treatment also did not affect the mean concentration of serum estradiol or progesterone. Supplemented ewes had higher conception (p = 0.06) and lambing rates (p < 0.05) compared with control. In conclusion, short‐term supplementation with rumen‐protected fat as a source of energy around breeding time improved metabolism, conception and lambing rates of ewes without effects on steroidogenic capacity and ovarian activity being apparent.  相似文献   

Expression of Perilipin 2 (PLIN2) in Porcine Oocytes During Maturation     

RN Zhang  XW Fu  BY Jia  C Liu  KR Cheng  SE Zhu 《Reproduction in domestic animals》2014,49(5):875-880

Perilipins have been reported to limit the interaction of lipases with neutral lipids within the droplets, thereby regulating neutral lipid accumulation and utilization. This study aimed to identify the location and expression of PLIN1 and PLIN2 in porcine oocytes during maturation. Quantitative real‐time polymerase chain reaction (qRT‐PCR), immunostaining and Western blot methods were used to characterize the expression and distribution patterns of PLIN1 and PLIN2 in porcine oocytes. The results showed that PLIN1 was not detectable in porcine oocytes. PLIN2 and BODIPY 493/503‐detected neutral lipid droplets appeared identical distribution patterns and extensive colocalization in both GV and MII porcine oocytes. PLIN2 protein expression was higher in GV oocytes than that in MII oocytes (p < 0.05), although PLIN2 mRNA expression was similar in both groups. These findings suggested that PLIN2 was a major lipid droplet‐associated protein in porcine oocytes.  相似文献   

A Large‐scale,Rapid Public Health Response to Rabies in an Organ Recipient and the Previously Undiagnosed Organ Donor     

R. M. Wallace  D. Stanek  S. Griese  D. Krulak  N. M. Vora  L. Pacha  V. Kan  M. Said  C. Williams  T. H. Burgess  S. S. Clausen  C. Austin  J. Gabel  M. Lehman  L. N. Finelli  G. Selvaggi  P. Joyce  F. Gordin  D. Benator  A. Bettano  S. Cersovsky  C. Blackmore  S. V. Jones  B. D. Buchanan  A. I. Fernandez  D. Dinelli  K. Agnes  A. Clark  J. Gill  M. Irmler  D. Blythe  K. Mitchell  T. J. Whitman  M. J. Zapor  S. Zorich  C. Witkop  P. Jenkins  P. Mora  D. Droller  S. Turner  L. Dunn  P. Williams  C. Richards  G. Ewing  K. Chapman  C. Corbitt  T. Girimont  R. Franka  S. Recuenco  J. D. Blanton  K. A. Feldman 《Zoonoses and public health》2014,61(8):560-570

This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post‐symptom onset. In response to an organ‐transplant‐related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post‐exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation.  相似文献   

Effect of varying density and water level on the spawning response of African catfish Clarias gariepinus: Implications for seed production     

Gamal O. El Naggar  George John  Mahmoud A. Rezk  Waheed Elwan  Mohammed Yehia 《Aquaculture (Amsterdam, Netherlands)》2006,261(3):904-907

The development of a reliable methodology for spawning of African catfish, Clarias gariepinus without the use of hormone injections would greatly improve the prospects of aquaculture in Africa. Earlier work has shown that it is possible to produce C. gariepinus fingerlings by subjecting the broodfish to a physical stress of reduced water depth and/or increased temperature. The hypothesis that C. gariepinus could be induced to spawn through a combined physical stress of lowered water level and increased stocking density was tested in concrete tanks. Three water levels (25, 50 and 75 cm) and three stocking densities (2, 4 and 6 pairs of broodfish at a 1:1 sex ratio in each hapa) were tested. Water depth in the tanks and brood fish density in the hapas affected spawning success. The percentage of spawning females was significantly higher when broodfish were stocked at 2 and 4 pairs in each hapa at water levels of 25 cm or 50 cm. There was no significant difference in spawning response between the 25 and 50 cm depths while a significant difference was seen between the 75 cm and both 25 and 50 cm depths. The results indicate optimum levels and densities for enhancing spawning success in C. gariepinus.  相似文献