Articles containing the keyword 'sapwood'

The effects of two alternative formulations of sapwood senescence on the behaviour of model LIGNUM (with parameter values adjusted for Scots pine (Pinus sylvestris L.) growing southern Finland) were studied. The two alternatives were autonomous sapwood senescence assuming a maximum age for the tree ring, and sapwood senescence that is controlled by the mortality of foliage. For the latter alternative two hypothetical further mechanisms were stipulated. All the formulations were implemented in LIGNUM. Simulations were made with all model variants for fertile and poor soil conditions using high, normal and low rates of foliage mortality. The simulation results were compared against of a data set consisting of 11 open grown Scots pine trees from southern Finland. Observations of heartwood proportion were used in this study. They show that heartwood starts to increase in trees from age of approximately 20 years onwards. The simulation results showed no differences between fertile and poor soil conditions as regards heartwood formation. Of the variants of foliage-controlled sapwood senescence the one where death of sapwood in a tree segment induces sapwood senescence in the tree parts below only slightly was the best. This and the autonomous sapwood senescence corresponded equally well to the observations. In order to make more refined conclusions additional data and simulations are necessary.

• Sievänen, E-mail: rs@mm.unknown
• Nikinmaa, E-mail: en@mm.unknown
• Perttunen, E-mail: jp@mm.unknown

In laboratory studies the heartwood content seems to be the only natural property of a wood of different tree species influencing the decay resistance. Moistening and drying by diffusion happen quite slowly. Scots pine (Pinus sylvestris L.) sapwood takes moisture by capillary action quicker than pine heartwood and Norway spruce (Picea abies (L.) H. Karst.) wood. Swelling and shrinkage are also greatest in pine sapwood. Impregnation of pine sapwood can give it better hydrophobic and dimensional stability than that of pine heartwood.

The PDF includes an abstract in English.

• Kärenlampi, E-mail: pk@mm.unknown

The sustainability of native forests in Sub-Saharan Africa depends on the diversification of sources to generate bioenergy, and Eucalyptus spp. wood has been highlighted. However, the determination of energy quality parameters has been a challenge to enable plantation wood to generate energy. The research assessed the ash content of radial and longitudinal samples of Eucalyptus grandis (Hill) clone with different ages and growth sites. Samples were collected in three pre-established plots in the center of Mozambique. Five trees were cut down in each plot and six discs were removed from each tree. Grinded samples with <0.5 mm particle size were generated from the heartwood and sapwood of each disk to determine the ash content. Wood from 7-year-olds had a higher ash content compared to 9-year-olds. The two sample plots differed from each other in terms of wood ash content. Heartwood samples had smaller ash content than sapwood samples. In general, the ash content of the intermediate positions was lower than those from the base and top of the stem, for both radial sections. No conclusive differences were found between samples from the base and the top of the trees, indicating that the material from the top of the trees can also be used as wood fuel. Ash content can be a considerable parameter to assess the quality of the wood of Eucalyptus spp. as a fuel.

• Mogeia, Universidade Lúrio, Faculdade de Ciências Agrárias, Departamento de Silvicultura e Maneio [Lurio University, Faculty of Agricultural Sciences, Department of Forestry and Management], Campus de Wanaango, EN733, Km 42, Unango, Niassa, Mozambique E-mail: smogeia@unilurio.ac.mz
• Manhiça, Centro de Investigação Florestal, [Forestry Research Center], Marracuene, EN1, Maputo província, Mozambique E-mail: albertomanhica@gmail.com
• Egas, Universidade Eduardo Mondlane, Faculdade de Agronomia e Engenharia Florestal, Departamento de Florestas, [Eduardo Mondlane University, Faculty of Agronomy and Forestry Engineering, Department of Forests], Av. Julius Nyerere, Maputo cidade, Mozambique E-mail: aegas8@gmail.com

The paper aimed at testing the potential of refining tree rot diagnostics carried out by means of electrical impedance tomography (EIT). Examined was the use of EIT datasets with electrical resistance values and sapwood proportion determined on the basis of tomograms. Making use of datasets with resistance values in EIT rot diagnostics is not a default method, although datasets stay unaffected by a fixed colour scale and subsequent subjective evaluation unlike tomograms. Tomography measurement was carried out for 27 individuals of Norway spruce (Picea abies [L.] Karst.) in two stands north-east of Brno, Czech Republic. Once felled down, radial cut-outs were sampled at the measurement site and used for localising rot and determining the extent of the area of decay. The results were subsequently compared with tomograms. EIT datasets containing values of electrical resistance found by measuring were statistically processed and compared with the extent of rot area identified within the cuts. Sapwood proportion values were also detected using the tomograms. The baseline assumption that sapwood proportion decreases as the rot area in the radial cut expands was confirmed. In trees with rot percentage to 35% approximately, sapwood proportion was exceeding 30% except one tree. In trees with rot percentage exceeding 35%, sapwood proportion was below 30%. On the basis of interpreted datasets, the trees can be split into three characteristic groups that correspond to the occurrence, extent and nature of the rot.

• Humplík, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic E-mail: premysl.humplik@mendelu.cz
• Čermák, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic E-mail: petr.cermak@mendelu.cz
• Žid, Mendel University in Brno, Faculty of Forestry and Wood Technology, Zemědělská 1665/3, 613 00 Brno, Czech Republic E-mail: tomas.zid@mendelu.cz

• Kiser, P.O. Box 3729, Pagosa Springs, Colorado, USA E-mail: jim.kiser@parelli.com

• Bieker, University of Applied Sciences and Arts, Faculty of Resource Management, Büsgenweg 1a, D-37077 Göttingen, Germany E-mail: db@nn.de
• Rust, University of Applied Sciences and Arts, Faculty of Resource Management, Büsgenweg 1a, D-37077 Göttingen, Germany E-mail: rust@hawk-hhg.de

• Pérez, Ambiente Tierra S.A., Apartado 733-2250, Tres Ríos, Cartago, Costa Rica E-mail: diegoperez@costarricense.cr
• Kanninen, Center for International Forestry Research (CIFOR), Bogor, Indonesia E-mail: mk@nn.id

• Björklund, Swedish University of Agricultural Sciences, Department of Forest Management and Products, S-750 07 Uppsala, Sweden E-mail: lars.bjorklund@sh.slu.se