Natural regeneration of broadleaved tree species in southern Sweden

The objective of the present thesis was to examine the effects of silvicultural treatments and seed dispersal from surrounding stands on the establishment of natural regeneration of broadleaved tree species in southern Sweden. Most of the broadleaved tree species that occur naturally in forests in southern Sweden were studied but birch (Betulapendula Ehrh.1 B. pi~besceizs Roth) was the most common species and present in equal numbers in all studies. The wind dispe.rsa1 of see.ds of se.ven species was studied and great variations were found. This could mainly be explained by differences in seed morphology. The effect of soil scarification was examined in all five studies and was generally found to be positive for the establishment of the studied broadleaved species. However, in some cases the scarification was not positive for the establishment. The reason for t l i s was hypothesised to be that the seed supply was limited, or an effect of large and/or animal-dispersed seeds. The effect of shelterwood w a s examined in three studies and was found to be positive for animal-dispersed species but negative for shade-intolerant species, although a sparse shelterwood can be used to rcgcncratc birch. Slash removal was included in onc study and found to be positive for thc cstnblishrncnt of birch. This thcsis showccl that regeneration trcatmcnts can be used to incrcasc the e.stablishnent of naturally regene.rated broadleaved tree seedlings, but the stand structure and species composition must be regulated with pre-commercial thinning. However, the effect of variations in seed production and seed dispersal must be closely examined from a time and a space perspective prior to any forecasts regarding the effects of regeneration trcatrn

Astrophysical and cosmological probes of dark matter

Dark matter has been introduced to explain mass deficits noted at different astronomical scales, in galaxies, groups of galaxies, clusters, superclusters and even across the full horizon. Dark matter makes itself felt only through its gravitational effects. This review summarizes phenomenologically all the astrophysical and cosmological probes that have been used to give evidence for its existence.Comment: 40 pages, 24 figures. Published in J. of Modern Physics 3, 1152, 2012. Minor corrections and additions in Versions 2 and 3. arXiv admin note: text overlap with arXiv:0809.2783, arXiv:1103.2772, arXiv:1204.3377, arXiv:1111.4983, arXiv:0809.0898, arXiv:1004.1559, arXiv:0705.3323 by other author

Resurrection of the Sigma Meson

It is shown from a very general model and an analysis of data on the lightest 0++ meson nonet that the f0(980) and f0(1200) resonance poles are two manifestations of the same ss state. Similarily the a0(980) and the a0(1450) are likely to be two manifestations of the same qq state. On the other hand, the uu+dd state, when unitarized and strongly distorted by hadronic mass shifts, becomes an extremely broad Breit-Wigner-like background, m=860 MeV, Gamma=880 MeV, with its pole at s=(0.158-i0.235) GeV^2. This we identify with the sigma meson required by models for spontaneous breaking of chiral symmetry.Comment: 13 pages in Latex using RevTex (and psfig.sty), 4 figures available as ps files from N. To"rnqvist ([email protected]) on reques

Rundbalsensilering

Sammandrag av en litteraturstudie av Matts Nysand. Litteraturstudien i sin helhet publiceras på finska som Vakolan tutkimusselostus no 55

Säilörehun korjuu pyöröpaalaimella

Julkaisu on pääosin tiivistelmä Matts Nysandin tekemästä kirjallisuustutkimuksesta, joka julkaistaan Vakolan tutkimusselostuksena n:o 55 (1989)