Articles containing the keyword 'juuristo'

Containerized tree seedlings will be used on an increasing scale in the future in different parts of the world. There are number of techniques for the production of small one-year-old seedlings but it has not been possible to develop a completely satisfactory methods for large containerized seedlings production. In the long-term development of pine plantations established with containerized seedlings the greatest problem has been deformation of the root system. With a new method, based on a sheet of peat and root pruning, it has been possible to produce conifer seedlings with a good root regeneration potential and favourable morphological root system development. The use of small containerized seedlings allows an increase in planting density without any marked increase in regeneration costs.

The PDF includes an abstract in English.

• Parviainen, E-mail: jp@mm.unknown

The structure and functional responses of roots in planted seedlings when acclimatizing at the planting site are reviewed. A wide range of methods for classifying roots has been employed, and the terminology used is not uniform. Roots can be classified by their morphology, origin, and function. The temporal and spatial variation of soil temperature, moisture, structure, and concentration of nutrients are among the most important properties to which root systems acclimatize. In order to reliably describe the function of the root system, several parameters usually have to be measured. Studies on the root-soil interface have indicated that roots are not necessarily in continuous contact with soil. The control mechanism of root growth is inadequately known and theoretically formulated. Generally, only the mass needed for water and nutrient uptake has been allocated to the roots. However, the amount of photosynthates allocated to the roots is high. Acclimatization of seedlings out at the planting site is a complicated process which is influenced by the growing conditions at both the nursery and at the site. The function, distribution and structure of roots are controlled by the environment in a way similar to the shoot, but the control mechanism is imperfectly known.

The PDF includes an abstract in English.

• Lippu, E-mail: jl@mm.unknown
• Puttonen, E-mail: pp@mm.unknown

This project studied the value of various shoot and root-system characteristics as indicators of plantability of transplants. Correlation and regression analysis was used to compare these characteristics. The study material consisted of two-year Scots pine (Pinus sylvestris L.) transplants that had grown in a plastic greenhouse for the first year and then been transplanted in the open. The seedlings had been transplanted in the field without treatment or with the roots cut to a length of 8 cm. A part was transplanted without treatment into plastic pails. A gravimetric and photometric method was used to obtain a description of the surface area of the root systems.

The results show that the photometric value gives a good picture of the surface area of the root system. The greatest advantage offered by the method is the simplicity and rapidity of measurement. The gravimetric, and especially the titrimetric, measurement takes much more time per plant. Photometric measurement affects plantability little, and measured and planted transplants can be followed up in the field. In gravimetric measurements, it was found that fresh and dry weight of the plants were closely correlated.

Mycorrhizal frequency in the root systems gave a good picture of the surface area of the root system. The number of living roots-tips was also rather closely correlated with the surface area of the root system. The other morphological characteristics failed to serve as a satisfactory index for the surface area of root systems. The one closest correlated was the annual leader growth. The second best was stem diameter; the height of the plant, on the contrary, was rather poorly correlated with the other characteristics.

The PDF includes a summary in English.

• Lähde, E-mail: el@mm.unknown
• Oksanen, E-mail: ao@mm.unknown

Silva Fennica issue 52 includes presentations held in professional development courses, arranged for foresters working in public administration in 1938. 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 growth and form of root systems of different tree species in different sites and how growth of roots affect forest management.

• Aaltonen, E-mail: va@mm.unknown

Draining transforms root systems of trees growing in peatlands towards the ones growing on mineral soil. However, even after efficient draining the root systems differ from the root systems of trees growing on mineral soil. This investigation concentrates on root systems of forests of similar mire types growing in similar draining conditions but having different tree species compositions. The peatland, situated in Pieksämäki in Southern Finland, was drained in 1937. Sample plots, measured in 1956, consisted of mixed forest of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst.) and birch (Betula sp.) in different compositions, and were in natural condition.

The sedge pine bog studied in this investigation was shown to have larger total amount of roots and mycorrhiza than in previously studied dwarf shrub pine bogs. This reflects better growth conditions of the better site. The depth of root system was, however, similar. Root systems of birch were deeper than those of the coniferous tree species. Differences between Scots pine and Norway spruce were small. Corresponding differences between the species were found in the density and total number of mycorrhizas. The abundance of mycorrhizas in the roots of birch increased in deeper layers of peat, but decreased especially in spruce roots. In earlier studies the abundance of mycorrhizas decreased in the roots growing in deeper layers in pure Scots pine stands, but no such variation was seen in this study. The result suggest that the deep root system of birch may affect also the root systems of the coniferous trees. On the other hand, birch roots can have advantage over the coniferous trees.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown

The root system of a Scots pine (Pinus sylvestris L.) growing on a peatland is restricted, according to earlier studies, on the top layers of the peat above the groundwater level. Drainage of the peatland affects growth of the root system. This investigation aims at studying the root systems on the point of view of draining of peatlands. The structure and distribution, and the growth of mycorrhiza in Scots pine roots in pine swamps varying from natural state to well drained state is studied.

The study shows that Scots pine on pine swamps has more extensive root system than has earlier assumed, it is common to find 1,000 m of roots in one cubic meter in a healthy stand. The trees reach this density of roots early on. In a drained peatland, the total root length is markedly higher than in a similar stand in natural state. The root systems proved to be very shallow. Even in a well-drained site the roots did not grow deeper than 20 cm. 70% of all roots were found in the upper 5 cm layer of peat, and 90% in the upper 10 cm layer. Root systems were deeper in drained peatlands, but the difference was small. In a site in natural state the average depth of the roots was 4 cm, and in a drained site 5 cm. About 85% of the roots were under 1 mm of diameter. Short roots were found only in the fine roots. Draining increases strongly the number of short roots. Mycorrhizas of the types A, B, C and D as well as pseudomychorrizas were found in the pine roots.

The PDF includes a summary in German.

• Heikurainen, E-mail: lh@mm.unknown

Root systems of a Scots pine (Pinus sylvestris L.) stands of seed trees on a Vaccinium sites in Southern Finland were studied by taking soil samples around the seed trees. The results show that root system of an old Scots pine spreads relatively evenly around the tree up to at least 10 meters from the stem. The densest part of the root system is near the stem, which part is often acentric. This is probably due to root competition in the early stages of growth of the tree.

Root systems of the seed trees affect stocking of the site with seedlings and the growth of the seedlings. The root competition can cause, for instance, uneven grouping of the seedlings. It seems that the largest trees of a stand have the most even root system. It is therefore recommended to choose the strongest trees of the stand as seed trees, to ensure even distribution of 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.

• Kalela, E-mail: ek@mm.unknown

Observations of connections between the roots of living trees and root systems of stumps have been reported already in 1900s. In Finland root connections have been found in Birch (Betula sp.), Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.), but there are no studies on abundance of the connections. This investigation studied root connections in a series of naturally regenerated Scots pine stands from seedling stands to mature trees in Southern Finland, and some sown seedling stands.

Root connections were found to be common in naturally regenerated, older stands that had passed the thicket stage. Approximately 21-28% of the trees had at least one root connection to another living tree, dead tree or living stump. Connections were few or absent in seedling stands. Sown seedling groups had many root connections in contrary to naturally regenerated seedling stands. Trees belonging to the dominating canopy class had most root connections. The trees could form a network of up to twenty trees and living stumps. Root connections were more common the larger the tree was or the nearer the trees grew each other. The coalescent roots were often situated near the stem. Experiments showed that water and nutrients transferred in the roots could move from one tree to another. Living stumps from previous fellings were relatively common. In the sites studied, there was in average 178 stumps connected to a living tree per hectare.

The PDF includes a summary in German.

• Yli-Vakkuri, E-mail: py@mm.unknown

Norway spruce (Picea abies (L.) Karst.) invading sites is common in Finland. The species tends to establish itself as undergrowth, and takes over when it gets space to grow. To determine whether the undergrowth is suitable as the new generation requires knowledge on the biology of spruce undergrowth. One of the issues is determining the age of the stunted trees. In this investigation, 100 undergrown spruce trees, their crown and their root systems were studied. A method was developed to determine the age of the trees.

The root system of all trees in Vaccinium sites and of stunted trees in Myrtillius sites were superficial. The root systems of older spruces were purely of adventitious origin. The longer the period of stunting growth, the younger is the root system. In addition to acropetal and general adventitious ramification there is often adventitious branching of the roots of pathological causes. Mortality among the long roots is frequent.

A stunted tree has not the same ability as a viable tree to make use of already existing branches for building assimilating surface. When comparing trees with equally large assimilating surface, a stunted tree had greater sum of roots compared to a viable tree. The root system of a stunted undergrown spruce was very superficial compared with the other trees.

The PDF includes a summary in English.

• Sirén, E-mail: gs@mm.unknown

The purpose of the investigation was to study the amount, quality and distribution by layers of depth of horizontal roots in Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stands in Southern Finland. The sample plots included stands on soil varying from sandy to stony, and stands of  varying ages from seedling stands to an old stand, in Myrtillus and Vaccinium type forests.

In a Norway spruce stand, the amount of roots increases rapidly and reaches its maximum, about 450 meters/m³, at an age of 100-110 years. In a Scots pine stand the maximum, about 370 m/m³, is reached earlier, at an age of 60-70 years. The root system of pine expands more rapidly than that of spruce. The total length of the horizontal root system of pine amounts to 1,000 m soon after 40 years of growth, of spruce at the age of 60. Later the situation changes, and at the age of 110 the root systems of both species are about the same size, but older trees of spruce have more extensive root system.

Majority of horizontal roots are under 1 mm in diameter. Of the horizontal roots of spruce stands the majority lie in the humus layer and in the topmost mineral soil stratum. Over half of horizontal spruce roots are, thus, at a maximum depth of 5 cm, while majority of the roots of Scots pine lie at maximum in depth of 10 cm. At the same layer grow also the roots of the ground vegetation, which may affect the competition between the species.

The PDF includes a summary in English.

• Kalela, E-mail: ek@mm.unknown

The study is based on observations in a Scots pine (Pinus sylvestris L.) stand on a dry upland forest site in Karhumäki, where a 10-15-year old seedling stand grew under a hold-overs of larger trees that had been left in the site in a previous felling. The root systems of 80-120 cm tall seedlings growing around single mother trees were unearthed. Root maps were drawn of the root systems of 120 seedlings.

No seedlings grew around old, large hold-overs. It seems that seedlings could not compete with their root system. If the hold-overs were stunted in their growth, seedlings grew also under the canopy of the mother tree. 90% of the seedlings had a tap root. Rest of the roots grew horisontally in the topsoil. Around a vigorous mother tree, the seedlings grew their roots away from the mother tree. Hold-overs that had belonged originally to the lower canopy layer of the old forest did not have similar effect on the root orientation of the seedlings. Their roots had been previously affected by trees of higher canopy layer, later removed in the felling.

The PDF includes a summary in German.

• Kalela, E-mail: ek@mm.unknown

Shifting cultivation, practiced earlier in Finland, was beneficial for grey alder (Alnus incana (L.) Moench). It can produce seeds early and the early growth of the seedlings is fast. Areas where shifting cultivation was intensive, the areas next to the fields were pure alder stands, next circle was Betula sp. dominated, beyond that could be found Scots pine (Pinus sylvestris L.), and finally Norway spruce (Picea abies (L.) H. Karst.). When shifting cultivation ended, Norway spruce became more common. Many young mixed stands had Norway spruce undergrowth and alder overgrowth. The aim of the study was to find out how the stands develop to spruce dominated stands, and how they should be managed.

The density of spruce undergrowth affects the further development of both spruce and alder. The number of alder stems decreases the faster the denser the spruce undergrowth is. Alder overgrowth slow down the early diameter and height growth of spruce compared to pure stands. Also the diameter and height growth of alder remains smaller in mixed stands. The basal area of spruce develops slowly in the beginning, increases significantly by the age of 30, and surpasses the growth of pure spruce stands in Oxalis-Myrtillus site type. Thus, Norway spruce do not suffer from growing in the undergrowth. In the first years, fast growing alder seedlings limits growth of ground vegetation and protects spruce seedlings from frost.  Later thinning or removal of alder benefits spruce growth. The density of spruce undergrowth decides how much alder can be leaved in the stand. If the spruce undergrowth is thin, more alder can be left in the stand.

The PDF includes a summary in German.

• Kalela, E-mail: ek@mm.unknown

About 40% forest in Finland are mixed stands that have birch (Betula pubescens and B. verrucosa) as one of the species. The aim of this research was to study the structure of root system of birch and compare it to the other main tree species in Finland.

The root systems were dug out and measured in 28 sample plots in Southern and Central Finland, representing different forest site types. Birch roots correspond 30‒100% of the volume of the stem, the largest root systems being in the sandy soils or peatlands. Also the longest lateral roots can be found at these sites. The size variation of root system of birch is larger than in Scots pine (Pinus sylvestris L.), and the vertical root system is in general smaller in birch. Birch seems to be better than pine able to adapt its root system to the existing conditions. The smallest root systems were found in the good forest site types, but the roots grow in the good sites denser than in the poor sites. The lateral roots of the main tree species in Finland, birch, Scots pine and Norway spruce (Picea abies (L.) H. Karst.) grow in different depths, which decreases the competition between the species. This finding gives support to cultivation of mixed stands.

The PDF includes a summary in English.

• Laitakari, E-mail: el@mm.unknown