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Articles containing the keyword 'LESS'

Category : Article

article id 7350, category Article
Ilmari Paasio. (1941). Plant sociological principles of open bog types. Acta Forestalia Fennica vol. 49 no. 3 article id 7350. https://doi.org/10.14214/aff.7350
Keywords: population; classification; treeless bog; open bog; plant sociology; plant stand; phytogenesis
Abstract | View details | Full text in PDF | Author Info

The plant populations of Finnish open bogs are typically formed of two layers. The layers normally consist of one or rarely two species. The structure of plant populations in open bogs is a consequence of the development where determining factors are different site requirements of the species, and the differences in the biotic vitality and capacity for reproduction.

Phytogenesis should be taken as a basic unit for describing the plant societies or vegetation of treeless bogs. However, acknowledging the sub-populations may be of advantage for describing the ecological, genetic and regional characters of open bogs.

The basic classification of open bogs must be done based on the ground layer. The more detailed classification follows mostly based on field layer, partly also based on the ground layer.

The PDF contains a summary in Finnish. 

  • Paasio, E-mail: ip@mm.unknown (email)
article id 7011, category Article
Antti Tanttu. (1915). Tutkimuksia ojitettujen soiden metsittymisestä. Acta Forestalia Fennica vol. 5 no. 2 article id 7011. https://doi.org/10.14214/aff.7011
English title: Studies on forest growth of drained peatlands.
Original keywords: ojitus; räme; neva; korpi; turvekangas
English keywords: draining; pine swamp; treeless bog; spruce swamp
Abstract | View details | Full text in PDF | Author Info

Draining of peatlands to improve forest growth started to increase in Finland in the beginning of 1900s. The aim of the study was to find out which kind of peatlands are suitable for draining. The peatlands examined in this study had been drained earlier in 1800s for other purposes, and the original peatland type was deduced afterwards. When the peatland is drained, its vegetation changes gradually towards that of mineral soil sites, depending on the original peatland type. The article includes detailed description of the vegetation on different drained peatland sites. Best represented in the study were different types of pine swamps, which change towards Calluna or Vaccinium forest site type depending on the original peatland type. The Sphangnum species and brushwood disappear gradually and Cladina sp. become common in some drained pine swamp types. Scots pine (Pinus sylvestris L.) regenerates well on most drained pine swamps, and also Betula sp may grow as dominant species. The richer pine swamp types develop to Vaccinium-myrtillus forest site type, which may grow also Norway spruce (Picea abies (L.) H. Karst). Drained treeless bogs change first towards pine swamps. However, trees regenerate poorly on these sites and the growth is low. Flark-bogs develop typically to treeless lichen heaths. Drained spruce swamps develop to forest with grass-herb vegetation or Myrtillus site type.

The PDF includes a summary in German.

  • Tanttu, E-mail: at@mm.unknown (email)

Category : Research article

article id 189, category Research article
Lars Rytter, Gunnar Jansson. (2009). Influence of pruning on wood characters in hybrid aspen. Silva Fennica vol. 43 no. 4 article id 189. https://doi.org/10.14214/sf.189
Keywords: Populus tremula P. tremuloides; cicatrisation; faultless wood; twig angle; twig diameter
Abstract | View details | Full text in PDF | Author Info
Fast-growing hybrid aspens (Populus tremula L. x P. tremuloides Michx.) are currently of great interest in Sweden since they can produce biomass at high rates and, at the same time, can be used to produce higher value wood products. This study focuses on the effects of pruning hybrid aspen to improve its wood quality. About 50% of the trees in the experimental stand were pruned by removing twigs, at heights up to 4 m, when they were 7–8 years old. Ten years later, 20 pruned and 20 unpruned trees, representing four clones, were randomly selected. Ten knots or twig/stem junctions, respectively, per tree were exposed for inspection using a chain saw and examined. The results revealed that pruned trees cicatrised the knots within about three years and thereafter produced substantial amounts of faultless wood. In contrast, unpruned trees (which had retained almost 80% of their twigs, often as dry twigs with bark pockets) had produced small uneven amounts of quality wood. Removal of twigs with acute angles and/or large diameters resulted in greater colour defects and rot in annual rings outside the pruning position, but the time of cicatrisation was not significantly affected. The results show that pruning can be used to enhance the wood quality of hybrid aspen over a short time period, and that pruning should be performed early during the rotation period when branches are small, in order to minimize discolouration and rot in the new annual rings.
  • Rytter, The Forestry Research Institute of Sweden (Skogforsk), Ekebo 2250, SE-26890 Svalöv E-mail: lars.rytter@skogforsk.se (email)
  • Jansson, The Forestry Research Institute of Sweden (Skogforsk), Uppsala Science Park, SE-751 83 Uppsala E-mail: gj@nn.se

Category : Research note

article id 24027, category Research note
Julian Frey, Zoe Schindler, Patrick McClatchy, Christopher Morhart, Elena Larysch, Thomas Seifert. (2025). The 3D reconstruction of wood and leaves from terrestrial laser scanning – a case study on PAR measurements below a solitary Malus domestica tree. Silva Fennica vol. 59 no. 1 article id 24027. https://doi.org/10.14214/sf.24027
Keywords: terrestrial laser scanning; leaf geometry; LESS; light modelling; Malus domestica; PAR; structural tree model
Highlights: Direct reconstruction of leaf and wood polygons from terrestrial laser scanning data by open source software; Validation of reconstruction based on in-situ PAR measurements and direct comparison to a turbid voxel approach; High correlations between in situ PAR measurements and RTM simulation (r = 0.92).
Abstract | Full text in HTML | Full text in PDF | Author Info
In this paper, we present a new methodology that directly extracts the geometry of woody features (wood and bark) and foliage from 3D data originating from terrestrial laser scans. Our goal was to enhance the precision of radiative transfer models for modelling tree shading by using highly resolved 3D tree models. The approach was tested on a single apple tree (Malus domestica (Suckow) Borkh.) in a peri-urban setting and was validated by utilising an open-source radiative transfer model and comparing the simulation output with in-situ measurements of photosynthetically active radiation (PAR) as well as simulations utilizing turbid voxels of 0.2 m and 1 m edge length. The in-situ measurements of 60 PAR sensors showed a correlation coefficient (r) of 0.92 with the simulated light intensities for the reconstructed polygons which was higher than for the voxel-based approaches (0.2 m:  r = 0.85, 1 m: r = 0.73). We were able to demonstrate that our approach effectively simulates light extinction through the canopy. This innovative method has the potential to easily provide detailed insights into high resolution radiation patterns within forests, which are connected to multiple ecosystem functions like species and habitat diversity.
  • Frey, Chair of Forest Growth and Dendroecology, University of Freiburg, Freiburg im Breisgau, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID https://orcid.org/0000-0001-7895-702X E-mail: julian.frey@wwd.uni-freiburg.de (email)
  • Schindler, Chair of Forest Growth and Dendroecology, University of Freiburg, Freiburg im Breisgau, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID https://orcid.org/0000-0003-2972-1920 E-mail: zoe.schindler@wwd.uni-freiburg.de
  • McClatchy, Chair of Forest Growth and Dendroecology, University of Freiburg, Freiburg im Breisgau, Tennenbacher Str. 4, 79106 Freiburg, Germany E-mail: patrickjmcclatchy@gmail.com
  • Morhart, Chair of Forest Growth and Dendroecology, University of Freiburg, Freiburg im Breisgau, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID https://orcid.org/0000-0003-1874-5011 E-mail: christopher.morhart@wwd.uni-freiburg.de
  • Larysch, Chair of Forest Growth and Dendroecology, University of Freiburg, Freiburg im Breisgau, Tennenbacher Str. 4, 79106 Freiburg, Germany ORCID https://orcid.org/0000-0002-1191-5770 E-mail: elena.larysch@wwd.uni-freiburg.de
  • Seifert, Chair of Forest Growth and Dendroecology, University of Freiburg, Freiburg im Breisgau, Tennenbacher Str. 4, 79106 Freiburg, Germany; Department of Forest and Wood Science, Stellenbosch University, Private Bag X1, Matieland, 7602, Stellenbosch, South Africa ORCID https://orcid.org/0000-0002-9611-6272 E-mail: thomas.seifert@wwd.uni-freiburg.de

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