Current issue: 53(2)

Under compilation: 53(3)

Impact factor 1.683
5-year impact factor 1.950
Silva Fennica 1926-1997
1990-1997
1980-1989
1970-1979
1960-1969
Acta Forestalia Fennica
1953-1968
1933-1952
1913-1932

Articles containing the keyword 'knottiness'.

Category: Article

article id 7164, category Article
Veijo Heiskanen. (1965). Puiden paksuuden ja nuoruuden kehityksen sekä oksaisuuden ja sahapuulaadun välisistä suhteista männiköissä. Acta Forestalia Fennica vol. 80 no. 2 article id 7164. https://doi.org/10.14214/aff.7164
English title: Relation between the development of the early age and thickness of trees and their branchiness in Scots pine stands in Finland.

The objective of the study was to establish the influence of the founding density of a stand and the intensity of intermediate cutting on the quality of pine saw logs stems, primarily on their branchiness. Measurements were carried out in 68 Myrtillus-type and 32 Vaccinium-type Scots pine (Pinus sylvestris L.) stands. The quality of 1,982 sample trees was assessed.

According to the results, the branchless part of the stem is longest in the older age classes of trees. In all age classes the percentage of the branchless part is highest in medium sized stems. The relative height of the crown limit is greatest in small diameter classes and continues as the thickness of the tree increases. The crown is longer in the thicker tree. The grade of the butt log is on average highest in medium sized stems. Knottiness of a log made it unsuitable for a saw log only among the thickest stems. The relative share of the u/s grade decreased as the thickness of the trees increased.

From the point of view of early development of the trees it was concluded that in all age classes the branchless part is the shorter the faster the tree has grown in diameter when it was young. Also, branches of the butt log are the bigger the faster the tree has developed when it was young. The grade of the butt log improves as the thickness of the annual rings diminishes.

To produce good quality sawn timber, the pine stands should be established dense, and the first thinnings should be delayed as much as possible. The best time for the thinning would be when the diameter of the dominant trees at stump height is 12–15 cm and when all the branches have died on the length of the butt log. After the first thinning, comparatively intense intermediate thinning may be applied.

The PDF includes a summary in English.

  • Heiskanen, ORCID ID:E-mail:
article id 7317, category Article
Erkki Laitakari. (1935). Tutkimuksia metsikön ja kasvupaikan vaikutuksesta kuusen rungon kelpoisuuteen. Acta Forestalia Fennica vol. 41 no. 4 article id 7317. https://doi.org/10.14214/aff.7317
English title: Studies on the influence of stand and forest site type on the quality of Norway spruce stem.

Healthy, straight, more or less free from branches and slowly tapering stems are good raw material for woodworking industry. The aim of the study was to investigate, from the stand point of forest management, the influence of stand and forest site type on the technical quality of the stems. Sample plots were measured in Norway spruce (Picea abies (L.) H. Karst.) stands in Eastern Finland. Norway spruce growing in a stand with closed crowns developed thin branches and self-pruned, if the stand was dense in the early stages. The decisive time for the stand is, therefore, when it is at seedling stage and young stand. The stems are more branchy if the stand has been planted. The adequate planting density is discussed based on earlier studies. The sufficient density seems to be achieved when the spacing is at maximum two meters. When the stems are branchless up to four meters, thinning of spruce stand does not affect knottiness or stem form. A sparsely stocked, knotty young stand does not produce good-quality timber even if the stand is later dense. Selective thinning from above can be used to improve the quality of the wood.

The PDF includes a summary in German.

  • Laitakari, ORCID ID:E-mail:
article id 7302, category Article
M. Lappi-Seppälä. (1934). Karsimisesta ja sen metsänhoidollisesta merkityksestä. Acta Forestalia Fennica vol. 40 no. 25 article id 7302. https://doi.org/10.14214/aff.7302
English title: The silvicultural influences of pruning.

Pruning growing trees influences tree growth and value of the wood and yield of timber of the stand. Pruning living branches create open wounds on the stems that can risk the growth of tree species that are vulnerable to injuries. For instance, pruning has been shown to cause decay in Norway spruce (Picea abies (L.) H. Karst.), while Scots pine (Pinus sylvestris L.) can quickly heal over the branch scars. Pruning of living branches reduces the crown, the effect of which remains small if only the lowest branches are pruned. Pruning of dry branches has little effect on the health of the tree. The main objective of pruning is to improve the quality of timber. Knottiness decreases strength and appearance of timber. Pruning increases the yield of knot-free sapwood, which is especially valuable in veneer timber. Pruning is, therefore, at present most suitable for birch and aspen which are used in veneer industry. In both species pruning should be directed mainly to dry branches.

The PDF includes a summary in German.

  • Lappi-Seppälä, ORCID ID:E-mail:
article id 5266, category Article
Matti Kärkkäinen. (1986). Malli männyn, kuusen ja koivun puuaineen oksaisuudesta. Silva Fennica vol. 20 no. 2 article id 5266. https://doi.org/10.14214/sf.a15445
English title: Model of knottiness of wood material in pine, spruce and birch.

A computer model was developed for predicting knottiness of wood material of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp). The prediction included location of knots, their size and quality, i.e. if they are dead or living knots. The model suits best for tree species where branches are born at the base of shoots, in Finland such tree species is Scots pine.

The usefulness of the model was tested in the prediction of knots in wooden elements of joinery industry. According to the results, the shape of cross section affects the surface quality of elements. Especially useful is a quadratic cross section as it increases the probability to get a knotless surface.

The PDF includes an abstract in English.

  • Kärkkäinen, ORCID ID:E-mail:
article id 5246, category Article
Matti Kärkkäinen, Markku Halinen. (1985). Mäntysahatukkien minimivaatimusten täsmentäminen. Silva Fennica vol. 19 no. 3 article id 5246. https://doi.org/10.14214/sf.a15425
English title: Reappraisal of minimum requirements of Scots pine saw logs.

A test sawing was made of 807 Scots pine (Pinus sylvestris L.) saw logs of varying size and quality. The most important knot characteristic affecting the value of sawn goods was the diameter of the thickest dry knot. The new minimum requirements for pine logs were proposed on the basis of top diameter of the log and the diameter of the thickest dry and living knot.

The PDF includes a summary in English

  • Kärkkäinen, ORCID ID:E-mail:
  • Halinen, ORCID ID:E-mail:
article id 4760, category Article
Veijo Heiskanen. (1968). Kuusitukkien laatuluokkajakautuma Etelä-Suomessa. Silva Fennica vol. 2 no. 1 article id 4760. https://doi.org/10.14214/sf.a14544
English title: Grade distribution of Norway spruce logs in Southern Finland.

The aim of the present study was to find the factors influencing the distribution of Norway spruce (Picea abies (L.) H. Karst.) logs on various grades with special stress on the effects of the grade on the value of logs. The material was obtained from ten sawmills located in Southern Finland by grading a total of 13,559 logs.

The results showed that knottiness in its different forms of appearance is the most important factor influencing the quality of spruce logs. Its significance is clearly greater in spruce than in Scots pine saw logs. Among the other defects, the most common are crooks. Even scars and decay occur to a considerable degree, but other defects seldom affect the grade. The quality of butt logs is markedly better than that of top logs. Both in butt and top logs the smallest logs in diameter are of poorer quality. However, in the largest diameter classes the quality begins again to decrease.

The difference in the quality of logs of the same grade at various sawmills is very small. The results of grading at varying times at the same sawmill show greater differences than can be observed between different sawmills. However, the logs of sawmills that procure the timber from coastal areas and islands are inferior to those which procure the timber from the mainland.

The PDF includes a summary in English.

  • Heiskanen, ORCID ID:E-mail:
article id 4516, category Article
M. Lappi-Seppälä. (1937). Karsimisesta arvopuun kasvatusta silmällä pitäen. Silva Fennica no. 42 article id 4516. https://doi.org/10.14214/sf.a14094
English title: Pruning as a means to produce quality timber.

 

 

  • Lappi-Seppälä, ORCID ID:E-mail:

Register
Click this link to register for Silva Fennica submission and tracking system.
Log in
If you are a registered user, log in to save your selected articles for later access.
Contents alert
Sign up to receive alerts of new content
Your selected articles

Committee on Publication Ethics A Trusted Community-Governed Archive