Template-Type: ReDIF-Article 1.0
Author-Name: D. Kaňová
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry, Brno, Czech Republic
Author-Name: E. Kula
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry, Brno, Czech Republic
Title: The effect of stress factors on birch Betula pendula Roth
Abstract: In a controlled pot trial, plants of birch (Betula pendula Roth) were treated in six variants: acid watering (pH 3), acid watering with spraying, drought, ammonium sulphate fertilisation, ammonium sulphate fertilisation in combination with drought, and control. The response to the treatment with ammonium sulphate in terms of the increment was discordant as it increased the sensitivity of birch to frost. Drought had a negative effect on increments. A combination of ammonium sulphate and drought; drought; ammonium sulphate and sprayed acid watering delayed the shedding of leaves; this was due to a longer vegetation period, significantly higher nitrogen content in these variants, with the exception of drought.
Keywords: Betula pendula, stress, acid rain, sulphur, nitrogen, drought, grow, phenology
Journal: Journal of Forest Science
Pages: 399-404
Volume: 50
Issue: 9
Year: 2004
DOI: 10.17221/4636-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4636-JFS.html
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Handle: RePEc:caa:jnljfs:v:50:y:2004:i:9:id:4636-JFS

Template-Type: ReDIF-Article 1.0
Author-Name: K. Ježek
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry, Brno, Czech Republic
Title: Contribution of regeneration on dead wood to the spontaneous regeneration of a mountain forest
Abstract: In the Moravian-Silesian Beskids in the beech/spruce forest vegetation zone, the amount of dead wood was determined (pieces of wood and stumps) in five sample plots in a managed forest and in three plots in the National Nature Reserve (NNR) Kněhyně-Čertův Mlýn. In plots situated in the managed forest, 22 to 50 m3/haof lying wood was found. In the reserve, the volume of fallen wood ranged from 29 to 144 m3/ha. The number of stumps in sample plots in the managed forest ranged from 530 to 980 per ha. In the reserve, the number of new stumps did not increase any more and only stumps from the period before the NNR declaration occurred. On the dead wood, spruce is regenerated nearly exclusively. In the managed forest and in the NNR, the number of regenerated spruce plants ranged from 5,000 to 16,000 and from 600 to 4,500 per ha, respectively. In plots where the sufficient amount of dead lying wood and stumps occurred, the proportion of spruce plants regenerated on the substrates amounted to even 75%. Other species (beech and silver fir) regenerated only on the soil surface. A sufficient amount of dead wood for the germination of seedlings can significantly ensure the natural regeneration of spruce in mountain forests.
Keywords: mountain forest, forest restoration, dead wood, natural regeneration, Norway spruce
Journal: Journal of Forest Science
Pages: 405-414
Volume: 50
Issue: 9
Year: 2004
DOI: 10.17221/4637-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4637-JFS.html
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Handle: RePEc:caa:jnljfs:v:50:y:2004:i:9:id:4637-JFS

Template-Type: ReDIF-Article 1.0
Author-Name: J. Urban
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry, Brno, Czech Republic
Title: Occurrence, development and natural enemies of cecidogenous generations of Pemphigus gairi Stroyan (Sternorrhyncha, Pemphigidae)
Abstract: The paper deals with the occurrence, development and natural enemies of the cecidogenous aphid Pemphigus gairi Stroyan (Pemphigidae). The aphid abundantly occurred on leaves of Populus nigra and P. nigra var. italica in Brno in 2003. It was described from England and no information on its occurrence is available in literature from continental Europe. It refers to a holocyclic and heteroecious species. In localities under study, larvae of fundatrices hatched mainly in the last decade of April. Through their sucking on the abaxial face of freshly unfolded leaves of poplars, species-unspecific lengthwise tile-like galls originate on the adaxial face of leaves (near the central leaf vein). During 12 to 14 days, fundatrices mature in galls of an average length and width 11.2 and 3.9 mm, respectively. Adults live about 1.5 months, namely max. until mid-July. They produce on average 75.6 fundatrigeniae which mature to winged migrantes alatae in the course of 16 days. In the period of hatching the first migrants (at the end of May), galls grow up to the final length of about 11.8 mm and width 4.7 mm. In primary slit-shaped caps on the abaxial face of leaves, migrants leave the galls through emergence holes. In a secondary host (Aethusa cynapium, Daucaceae), they produce on average about 17.5 larvae of exules. Owing to natural enemies (above all true bugs of the species Anthocoris minki), aphids die in 90% of galls.
Keywords: Pemphigus gairi, Populus spp., occurrence, development, galls, enemies, Anthocoris minki, importance
Journal: Journal of Forest Science
Pages: 415-438
Volume: 50
Issue: 9
Year: 2004
DOI: 10.17221/4638-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4638-JFS.html
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Template-Type: ReDIF-Article 1.0
Author-Name: M. Matějík
Author-Workplace-Name: Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry, Brno, Czech Republic
Title: Calculus of variations and its application to division of forest land
Abstract: The paper deals with an application of the least squares method (LSM) for the purposes of division and evaluation of land. This method can be used in all cases with redundant number of measurements, in this case of segments of plots. From the mathematical aspect, the minimisation condition of the LSM is a standardised condition ∑ pvv = min., minimising the Euclidean norm ||v||E of an n-dimensional vector of residues of plot segments at simultaneous satisfaction of the given conditions. The traditional procedure of calculus of variations with the use of Lagrangian function is shown. If some additional conditions are included in the calculation, on the basis of the criteria presented in this article it is possible to evaluate the degree of deformation of the selected solution in relation to the measured quantities. The application of the method of adjustment of condition measurements may help solve the problems of parcel division on the basis of intersection of the parcel layers according to the real-estate cadastre and according to previous land records, valuation, typological, price and other map sources.
Keywords: area, land, division of land, real-estate cadastre, mean square error, least square method, calculus of variations, adjustment with conditions
Journal: Journal of Forest Science
Pages: 439-446
Volume: 50
Issue: 9
Year: 2004
DOI: 10.17221/4639-JFS
File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/4639-JFS.html
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