Current issue: 58(5)
Articles containing the keyword 'luontainen uudistuminen'
Category : Article
In 1933, forest fire caused by locomotive sparkle burned about 600 hectares of forest in a forest district named Vehkatallinmaa, in Central Finland. In 1934–36, the burned area was reforested, using different sowing and planting methods. At the same time, areas with poor runoff were drained. The results from reforestation throughout the area have been good. Also, natural regeneration of coniferous trees, especially Scots pine (Pinus sylvestris L.) has occurred. Even deciduous trees, especially birch (Betula sp.), have regenerated naturally in the area. The forests are an evidence of the adaptability of broadcast sowing on snow crust as a method of reproduction.
The PDF includes a summary in English.
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Kolehmainen,
E-mail:
vk@mm.unknown
Silva Fennica issue 46 includes presentations held in professional development courses, arranged for foresters working in public administration in 1937. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.
This presentation describes forest regeneration on poor forest sites.
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Laitakari,
E-mail:
el@mm.unknown
Norway spruce (Picea abies (L.) H. Karst.) is rarely the dominant species on dry mineral soil sites in Northern Finland. These sites are, in general, too poor and dry for spruce, and suit better for Scots pine (Pinus sylvestris L.). According to the study, the natural regeneration of spruce is in Northern Finland poor. In the sample plots, cones could be found in 35% of spruce trees in the stands in natural state and 46% in the harvested stands. Compared to the spruce areas in Northern Finland, or fresh mineral soil sites in Southern Finland, cone and seed production of Norway spruce was in dry mineral soil sites very low due to scarcity of seed trees and their low cone number. There were few spruce seedlings in the sample plots, but according to the observations, spruce is able to regenerate on lichen and heath covered sites. The seedling growth was, however, poor on dry sites. Spruce seedlings were often found near fallen trees and stumps. The growing trees prevent growth of seedlings of all species. Norway spruce seems, however, to be able to spread also to the poor sites. The success depends on the vegetation and dryness of the site. For instance, spruce can spread to dry mineral soil sites from seed trees of nearby peatlands.
The PDF includes a summary in German.
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Tikka,
E-mail:
pt@mm.unknown
Category : Article
Pine swamps are easily regenerated by natural regeneration of Scots pine (Pinus sylvestris L.). Usually seeding felling is used, but also strip system or clear cutting and regeneration along stand edge has been suggested. This article discusses the regeneration by clear cutting and sparing the existing undergrowth. The article focuses on pine swamps to be drained and the ones in natural state.
Pine swamps in natural state usually have plenty of trees of smaller diameter classes, that can be trusted to form the future tree generation after the felling. This shortens the rotation by 20-30 years. The undergrowth has been shown to recover quickly. The method suits for regeneration of drained peatlands but could fit also for regeneration of pine swamps in natural state.
The seedlings in the pine swamps are mainly 1-5 years old, and the stock is changing. It seems that larger trees produce a wider selection of age groups, but the seedlings survive longer under smaller mother trees. Part of the younger generations of seedlings seem to be destroyed when the peatland is drained. Further studies are needed to investigate how the draining and felling are to be performed to spare the young seedlings.
The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
The PDF includes a summary in German.
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Heikurainen,
E-mail:
lh@mm.unknown
Natural regeneration has been common in Northern Finland, where forest fires have been usual, and the large areas make artificial regeneration expensive. The regeneration, and for instance tree species composition and density of the stand, cannot been controlled. In Northern Finland there is little demand for Betula sp. which is often abundant in the burnt areas. The unburned forests are generally Scots pine (Pinus sylvestris L.) or Norway spruce (Picea abies (L.) H. Karst.) dominated mixed forests with single Betula sp. trees.
The fire destroys birch for the most part in the Vaccinium site type, but the surviving trees produce enough seeds to regenerate the areas. The largest trees of Scots pine usually survive the fires. Pine has good seed years in the north only every 8th or 10th year. Spruce is totally destroyed in the forest fire and the seedlings grow poorly as primary species. The seedling stands are usually dominated by Scots pine and birch, but birch seedlings grow in batches, and do not hinder growth of pine. The drier Calluna site type stands are dominated by Scots pine. Birch seedlings may be abundant in the beginning, but most of them do not survive. Abundant emergent pine trees prevent the growth of seedlings especially in the dry site types, and they should be thinned to guarantee regeneration. Sowing results are better few years after the fire. The birch seedling should be removed from the seedling stands.
The PDF includes a summary in German.
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Sarvas,
E-mail:
rs@mm.unknown
The aim of the study was to determine the effect of grazing of the cutting areas to the ground vegetation and regeneration of spruce. The cutting areas could be divided into two kinds of areas based on the vegetation. Hillocks were drier and poorer than other parts of the cutting areas. Their vegetation did suffer less from grazing than the other parts of the cutting areas. The shade-loving plant species decreased, but as the poorer sites have less edible plants, cattle caused less damage than in the better sites. The even spaces between the hillocks had both positive and negative changes. Cattle transport seeds, tile and fertilize the soil, promote paludification, and decrease competition by the primary species like large grasses. This is beneficial to new species. Grazing is directed to large grass species like Calamagrostis. Those species that cattle reject, become more abundant. Stamping damages especially shallow rooted species and perennial species, like Norway spruce (Picea abies (L.) H. Karst.). Larger tree seedlings may get injuries in the stem.
The PDF includes a summary in German.
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Hertz,
E-mail:
mh@mm.unknown
The northern range of small leaved lime (Tilia cordata Mill.) in Finland has remained the same since the end of 1800s, but according to the studies of subfossiles of lime found in peatlands, the northern limit has once been higher than at the present. The northernmost natural specimens of the species in Reisjärvi do not produce seed, and are therefore probably a relict. The article includes a review on the distribution of the species in Finland and its capacity to regenerate. The natural regeneration of lime in Finland is at present very rare. The species has lost its ability to sexual reproduction, but reproduces readily vegetatively.
The PDF includes a summary in German.
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Hertz,
E-mail:
mh@mm.unknown
The frequency of years when Scots pine (Pinus sylvestris L.) produces cones and seeds affects its reproduction in the north. The study area covered most of the pine lands in Northern Finland. Scots pine seems to be able to produce cones relatively often in the north. The amount of seeds produced in one year was, however, not sufficient to produce a dense seedling stand. Thus, the natural pine stands contain usually trees in different ages-classes, which have germinated in different years. The cone production is highest in 150-170 years old trees. Pine also needs warm summers to produce viable seeds. Brush fires avail the growth of seedlings, because they clear of ground vegetation that hinders germination of seeds. The seedlings need also moisture to survive; good regeneration years have often had rainy summers.
The PDF includes a summary in German.
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Lassila,
E-mail:
il@mm.unknown
The fifth part of the six-article series about protection forest in Northern Finland outlines sustainable forest management practices for the Scots pine (Pinus sylvestris L.) forests in the pine timber line area. The author stresses the need to secure the seed production and regeneration capacity of the forests, and the growth and protection of seedlings. At the same time, the local communities’ need for timber has to be taken into account when considering the means to protect the pine forests. The main principle is not to cut more trees than has been regenerated during the time period between good seed years. The article outlines good forest management practices for the timber line area.
The article is divided in six parts. A German summary is in a separate PDF.
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Renvall,
E-mail:
ar@mm.unknown
This fourth part of the six-article series about protection forest in the Northern Finland is a proposal for organizing reindeer grazing to enable scots pine (Pinus sylvestris L.) regeneration near the timber line. Protection forests in the Northern Finland cover third of the natural pastures of reindeer in the area. In these areas reindeer grazing can harm the young pine seedlings. The proposal suggests temporary restrictions in grazing in the coniferous forests. Also, in the northernmost parts of Lapland the pine timberline area would be used only as winter pastures. Regional limits should be set for the number of reindeer. Also the ownership of reindeer herds and herding coopearatives included problematic issues that should be solved.
The article is divided in six parts. A German summary is in a separate PDF.
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Renvall,
E-mail:
ar@mm.unknown
The second part of the six-article series about protection forest in Northern Finland outlines the principles of protecting Scots pine (Pinus sylvestris L.) timber line. The protected areas should include at least all of the viable pine stands and those birch (Betula sp.) lands that are necessary to safeguard fuel wood supply in the pine forest zone. Outside the actual pine forest zone also those birch stands that are near populated regions should be protected to secure sustainable fuel wood supply. Third, south and down of the pine forest zone should be protected pine forest stands and adjacent open fell areas where forests are especially vulnerable. A new protection forest commission should be established to execute the protection forest legislation.
The article is divided in six parts. The parts II and III of the article series are included in the same PDF. A German summary is in a separate PDF.
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Renvall,
E-mail:
ar@mm.unknown
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.
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Ilvessalo,
E-mail:
li@mm.unknown
