Current issue: 53(3)

Under compilation: 53(4)

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 by Lauri Ilvessalo

Category: Article

article id 7251, category Article
Lauri Ilvessalo. (1929). Puuluokitus ja harvennusasteikko. Acta Forestalia Fennica vol. 34 no. 38 article id 7251. https://doi.org/10.14214/aff.7251
English title: Utilization of tree classification in thinnings.
English keywords: crown class; thinning method

Doctor Lauri Ilvessalo modified tree classification developed by professor Gunnar Schotte to develop a tree classification and thinning system that suited Finnish conditions. His system was first applied when the Finnish Forest Research Institute began thinning experiments in a large scale in 1924. The system distinguishes four crown storeys: the predominating crown storey, dominated crown storey, emergent trees and undergrowth. Into the predominating storeys belong dominant trees and co-dominant trees, and into the dominated storeys the intermediate and ground trees. The trees in all the storeys can be divided in to normal trees with well-formed crown and stem, trees with defectively developed crown, trees with defective stem, and injured and diseased trees. The article describes different thinning methods (cleaning thinning, selective thinning from below, selective thinning from above, increment felling, freeing felling) using the tree-classification.

The volume 34 of Acta Forestalia Fennica is a jubileum publication of professor Aimo Kaarlo Cajander. The PDF includes a summary in English.

  • Ilvessalo, ORCID ID:E-mail:
article id 7201, category Article
Lauri Ilvessalo. (1926). Forest research work in Finland : the origins and development of forest research work and a review of the investigations carried out up to date. Acta Forestalia Fennica vol. 31 no. 2 article id 7201. https://doi.org/10.14214/aff.7201

The article is a review of forest research carried out in Finland. The article includes a short review of the origins of forest research in the country and the research institutions in the country. It describes the main studies in different fields of forest research, divided on biological and silvicultural research, forest mensuration and forest policy research, and research on forest utilization.  English translation of the article was published at the same time with an Finnish article. A need for an English summary of the forest research was realized, because the publications have mainly been written in Finnish or German.

  • Ilvessalo, ORCID ID:E-mail:
article id 7200, category Article
Lauri Ilvessalo. (1926). Metsätieteellinen tutkimustoiminta Suomessa : metsätieteellisen tutkimustoiminnan synty ja kehitys sekä yleiskatsaus toimitettuihin tutkimuksiin. Acta Forestalia Fennica vol. 31 no. 1 article id 7200. https://doi.org/10.14214/aff.7200
English title: Forest research in Finland: the origins and development of forest research and a review of the investigations carried out up to date.

The article is a review of forest research carried out in Finland. The article includes a short review of the origins of forest research in the country and the research institutions in the country. It describes the main studies in different fields of forest research, divided on biological and silvicultural research, forest mensuration and forest policy research, and research on forest utilization. An English translation of the article was published at the same time. A need for an English summary of the forest research was realized, because the publications have mainly been written in Finnish or German.

  • Ilvessalo, ORCID ID:E-mail:
article id 7050, category Article
Lauri Ilvessalo. (1920). Ulkomaalaisten puulajien viljelymahdollisuudet Suomen oloja silmälläpitäen. Acta Forestalia Fennica vol. 17 no. 2 article id 7050. https://doi.org/10.14214/aff.7050
English title: Prospects of cultivating exotic tree species in Finland.

The article includes a dendrological review on the effect of climate to the success of cultivation of exotic tree species, based on literature and analysis of the existing Finnish field tests. The cultivation of an exotic tree species succeeds only if the seed has been procured from an area, which climate is similar to the place of cultivation. Climate is even more important than site quality.

Finnish climate is boreal and continental, and thus tree species of similar climate suit here best. In favorable site conditions it is possible to grow also species from boreal marine, and temperate climates. Finnish summers are not warm enough for species from temperate continental climate to get prepared for the winter, and the shoots can get frost damages. This may be compensated with a warm and sheltered site. If the species tolerates shading, it can be planted under sheltering trees. For species from maritime boreal climate, the Finnish summer tends to be too short, and the winters too cold. A suitable site is rich, warm and sheltered, and has preferably a protective sparse tree cover. Species from southern maritime climate cannot be grown in Finland. The provenance of the seeds is also very important. An important source of seeds are the successful plantations in Finland.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 7013, category Article
Lauri Ilvessalo. (1917). Tutkimuksia mäntymetsien uudistumisvuosista Etelä- ja Keski-Suomessa. Acta Forestalia Fennica vol. 6 no. 2 article id 7013. https://doi.org/10.14214/aff.7013
English title: Studies on the regeneration years of Scots pine forests in Southern and Central Finland.

The success of natural regeneration of Scots pine (Pinus sylvestris L.) is dependent on the amount and quality of seeds produced in each year. While seed production of Scots pine in Northern Finland is well known, there is little information about frequency of good seed years in Southern and Central Finland. The success of regeneration of Scots pine was studied by defining from the growth rings of felled sample trees in which year they started to grow. The aim was to choose sample trees so that they would form a continual series from seedlings to 100 years old trees. In the material there was too little sample trees from certain years. However, within the period of 1827-1910 it could be identified 13 good regeneration years of pine in Southern Finland. According to the study, pine has regenerated very well every 6th year and at least moderately well every 4th year. When compared to the previous studies made in Northern Finland, part of the good regeneration years seems to be same both in Northern and Southern Finland. Regeneration of Scots pine is affected also by the type and condition of the site.

The PDF includes a summary in German.

  • Ilvessalo, ORCID ID:E-mail:
article id 7529, category Article
Lauri Ilvessalo. (1913). Versuche mit ausländischen Holzarten im Staatsforst Vesijako. Acta Forestalia Fennica vol. 2 no. 2 article id 7529. https://doi.org/10.14214/aff.7529
English title: Experiments with foreign tree species in state forest Vesijako, Finland.

The study area is state owned forest of Vesijako in southern middle Finland that has earlier been intensively managed with slash-and-burn agriculture and then partly reforested with foreign coniferous tree species after controlled burnings. The total area planted with foreign species consists of 66 sample areas, altogether 28 hectares. The data has been collected in summer 1909. 

The most of studied sample areas have been unsuccessful, but there are still many areas that are too young to be assessed. The originally with foreign species reforested areas are now pine stands. The tree species in experiments have been e.g. larch (Larix sibirica and L. europaea), Siberian stone pine (Pinus cembra sibirica), Siberian fir (Abies sibirica o. pichta), balsam fir (Abies balsamea), white fir (Abies pectinate also Abies alba), white spruce (Picea alba also Picea glauca), Weymouth pinen (Pinus strobus) and European / Swiss mountain pine (Pinus montana  also P. mugo, P. mugho).

The most important result of the experiments with controlled burning is that stand of grey alder (Alnus incana) with only low economic value can be effectively altered into coniferous forests (Pinus silvestris).
  • Ilvessalo, ORCID ID:E-mail:
article id 4448, category Article
Lauri Ilvessalo. (1927). Ehdotus Suomen metsätieteellisen tutkimustoiminnan kehittämiseksi. Silva Fennica no. 7 article id 4448. https://doi.org/10.14214/sf.a8396
English title: Proposal for the development of forest research work in Finland.

National research has important role in creating the basis of forestry in Finland. The Forest Research Institute was established in 1918. In 1927 it had three departments: Department of Silviculture, Department of Forest Mensuration and Valuation and Department of Forest Soils. Each department had one professor and an assistant. Several areas of research are proposed to be expanded, and three new departments are suggested: Department of Swamp Investigation, Department of Forest Utilization and Department of Forest Economics. In addition, research workers should be hired in forest zoology and forest pathology.

The Society of Forestry (now: The Finnish Society of Forest Science) was established in 1909 to promote research in forest and wood science in Finland. It publishes two science journals, holds meetings and gives out grants for research. The society receives an annual state subsidy of 100,000 Finnish marks, which is almost entirely used to cover the costs of maintaining the society's publishing activities. Thus, very small means have been available, for instance, for grants for research work. The annual subsidy should be increased to 225,000 Finnish marks.

The PDF includes a summary in English.

  • Ilvessalo, ORCID ID:E-mail:
article id 4442, category Article
Lauri Ilvessalo. (1927). Cultivation of exotic tree species. Silva Fennica no. 4 article id 4442. https://doi.org/10.14214/sf.a8390

Successful cultivation of a tree species outside its natural area of distribution involves that the original climate is similar to that of the area where it will be cultivated. Seeds should be procured from an area, where the climate is most similar to the area of cultivation. In addition, the site requirements should be met. To be worth of cultivation, the exotic tree species should offer advantages over the native species, such as wood quality, higher productivity, modest site requirement, greater endurance against spring frosts and cold in the winter, valuable by-products, resistance against grazing, insects or fungi, or improvement of soil.

In Finland, successful examples are Larix europaea Lam. & A. DC. and Larix sibirica Lebed, which both give better yield than the native species, and have better resistance against decay. In Central Europe, Pseudotsuga mentziesii (Mirb.) Fnanko, Pinus strobus L. and Pinus sitchensis (Bong.) Carriére have proved to be good forest trees. In Hungary, Robinia pseudoacacia L. has become economically important. Eucalyptus spp. have been cultivated in the Mediterranean countries, South America and California.

A summary in Finnish is included in the PDF.

  • Ilvessalo, ORCID ID:E-mail:
article id 4435, category Article
Lauri Ilvessalo. (1926). Metsien säilymisen turvaaminen Karjalan kannaksen Suomenlahden rannikolla. Silva Fennica no. 2 article id 4435. https://doi.org/10.14214/sf.a8383
English title: Ensuring preservation of forests on the coast of Gulf of Finland in the Karelian Isthmus.

Metsähallitus (Forest Service) commissioned a study about condition of forests on the coast of Gulf of Finland in the Karelian Isthmus. The study was made because of a growing concern on overcutting of the private forests in the area. Dominant tree species in the area is Scots pine (Pinus sylvestris L.). In fresh mineral soil sites Norway spruce (Picea abies (L.) H. Karst.) grows in mixed forest with pine or as pure stands. The forests are in average 50 to 70 years old. Younger or older stands are less frequent.

At the beginning of 18th century the local peasants sold plots for Russians, and a villa area was created along the coast. When Finland became independent, many of the properties changed owners. Timber harvesting of the forests increased and many small sawmills increased the demand of wood. Because of the cuttings, productivity of the forests decreases and danger for wind damage in the forests increases.

The author suggests that legislation created to prevent deforestation as well as counselling should be applied to improve forest management. In addition, a protective area should be formed in the Karelian Isthmus where forest preserving directives should be followed.

A summary in German is included in the PDF.

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