Articles containing the keyword 'ring width'

Ring width at breast height is presented as a function of stem radius at breast height, the ratio between the diameter of a tree and the basal area median diameter, site index, and density of stand. By means of a conversion model ring width at stump height can be estimated as a function of ring width at breast height.

According to previous studies substantially better wood quality can be expected if mean width near the pith at stump height decreases from 3 to 2 mm. According to the present study only on the poorest sites suitable for Scots pine (Pinus sylvestris L.) planting (poor Vaccinium type) the ring width is less than 3 mm at stump height even in the thickest trees. On more fertile sites a substantial increase in the recommended planting density is required, if the mean ring width is aimed to be less than 3 mm. On the best sites it is impossible to reach mean ring width of less than 2 mm, when the density is less than 4,000 stems/ha. Only the thinnest trees on the poorest sites can have a mean ring width less than 2mm.

The PDF includes an abstract in English.

• Varmola, E-mail: mv@mm.unknown

Totally 653 battens and planks sawn from butt logsof Scots pine (Pinus sylvestris L.) were chosen from 3 saw mills. The sawn goods were sorted according to normal sorting principles. In order to determine growth rate in the youth, the mean value of the average ring width was measured at the butt end at various distances from the pith.

The average ring width increased as the quality of the sawn goods decreased. The difference between the quality classes in ring width was measured between 2 and 4 cm from the pith. As the size of sawn goods, and, simultaneously, the log size increased, the average ring width increased in a given quality class. Research reinforced previous results, in which slow diameter growth of young Scots pines has been shown to reflect the good quality of sawn goods.

The PDF includes a summary in English.

• Halinen, E-mail: mh@mm.unknown

Basic density and absorbed energy in impact bending were measured for 500 Norway spruce (Picea abies (L.) H. Karst.) samples from Northern and Southern Finland. Statistical analysis showed that the relationship between impact strength and basic density was significant and regression analysis showed that it was linear.

Furthermore, with constant density, the impact strength was higher in Northern than in Southern Finland. This was due to growth ring width: i.e. when density was kept constant the impact strength increased with decreasing growth ring width. In addition, when the growth ring width was kept constant, the basic density of wood was higher in Southern Finland than in Northern Finland.

The PDF includes a summary in English.

• Saranpää, E-mail: ps@mm.unknown

In order to evaluate the strength properties of boards made from small and large Norway spruce (Picea abies) butt logs, 15 small (top end diameter 13 cm) and 15 large (top end diameter 25 cm) logs were sampled from a sawmill in Finland. From each log two test pieces were made in order to measure the bending and compression strength, dry density and average ring width.

The boards from small logs were stronger and their density higher. When the differences between groups were analysed it was found that the strength was determined by the density and ring width. When the density was kept constant, the increase in ring width had a decreasing effect on the strength properties. Because there was a negative correlation between ring width and density, ring width alone had a great effect on the strength properties.

The PDF includes a summary in English.

• Kärkkäinen, E-mail: mk@mm.unknown
• Hakala, E-mail: hh@mm.unknown

After a decades-long increasing trend, the recent results of the National Forest Inventory (NFI) reported a decline of forest growth in North Finland. The aim of this study was to assess climatic and reproduction influences behind the growth decline. We used tree-ring data that had been collected by NFI using systematic sampling. The tree-ring width series were detrended using the regional curve standardisation (RCS) removing age-related trends. The resulting tree-ring indices of Scots pine (Pinus sylvestris L.) showed decadal variations with low increment in the 1990s, and high increment in the 1980s and the early years of the current century. Thereafter, a prolonged growth reduction for pine started both on the mineral soil sites and peatlands. The tree-ring indices of Norway spruce (Picea abies (L.) Karst.) had less pronounced decadal variations and no trend-like reduction over the last 15 years. High spring and summer temperatures were found to enhance radial growth, but high winter temperatures were related to low growth for pine and spruce in the following summer. Temperature variation, accompanied by variables indicating years of drought and intensive flowering, accounted for 34% annual growth variance of pine and 21–44% for spruce. Thus, the results imply that climatic factors may have to some extent contributed to the recent growth reduction of pine. Due to its ecological and economic consequences growth decline needs to be further monitored and investigated. Moreover, analyses of stand and age structure, potentially affecting the growth decline, were beyond the scope of this paper, but also warrant further investigation.

• Mäkinen, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki https://orcid.org/0000-0002-1820-6264 E-mail: harri.makinen@luke.fi
• Nöjd, Natural Resources Institute Finland (Luke), Latokartanonkaari 9, 00790 Helsinki E-mail: pekka.nojd@luke.fi
• Helama, Natural Resources Institute Finland (Luke), Ounasjoentie 6, 96200 Rovaniemi, Finland https://orcid.org/0000-0002-9777-3354 E-mail: samuli.helama@luke.fi

The ongoing climate change may have a distinct effect on Norway spruce growth, one of the most important tree species in European forest management. Therefore, the understanding and assessment of climate-growth relationship can help to reveal relevant patterns in temporal variability that may result in lower tree vitality and decline. The main objective of our study was to evaluate the long-term climate-growth variability of Norway spruce in south-eastern Norway, at the northern edge of the temperate zone. We sampled in total 270 dominant and co-dominant trees from 18 plots in south-eastern Norway. We analysed stem cores and evaluated crown condition parameters to assess the retrospective tree growth and vitality. Despite considerable differences in the crown parameters, high similarity among tree-ring width (TRW) series allowed compiling the regional tree-ring width chronology. Correlations between TRW and climate parameters showed temporal instability in their relationship during the period 1915–2012. While we did not detect any significant relationships between TRW and climate parameters in the first half of the study period (1915–1963), a significant correlation between TRW and spring precipitation was observed for the period 1964–2012. This shift appeared concurrent with temperatures reaching above-average values compared to the average of the climate normal period 1961–1990.

• Čermák, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic E-mail: cermacek@mendelu.cz
• Rybníček, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic E-mail: michalryb@post.cz
• Žid, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic E-mail: tom.z@centrum.cz
• Andreassen, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: Kjell.Andressen@nibio.no
• Børja, Norwegian Institute of Bioeconomy Research (NIBIO), P.O. Box 115, NO-1431 Ås, Norway E-mail: Isabella.Borja@nibio.no
• Kolář, Faculty of Forestry and Wood Technology, Mendel University in Brno, Zemědělská 3, 613 00 Brno, Czech Republic; Global Change Research Institute, The Czech Academy of Sciences, Bělidla 986/4a, 603 00 Brno, Czech Republic E-mail: koldatom@gmail.com

• Peltola, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heli.peltola@joensuu.fi
• Kilpeläinen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: ak@nn.fi
• Sauvala, Finnish Forest Research Institute, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ks@nn.fi
• Räisänen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: tr@nn.fi
• Ikonen, University of Joensuu, Faculty of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: vpi@nn.fi

• Lundgren, SLU, Dept. of Forest Products and Markets, P.O. Box 7060, SE-750 07 Uppsala, Sweden E-mail: christina.lundgren@spm.slu.se

• Pape, Swedish University of Agricultural Sciences, Department of Forest Yield Research, P.O. Box 7061, S-750 07 Uppsala, Sweden E-mail: rolf.pape@sprod.slu.se