Suo - Mires and peat 30 (1979)

Esko Savolainen. Lentokoneen ja helikopterin käyttö metsäojitusalueiden jälkitarkastuksessa.
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  • Savolainen, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Tapio Lindholm, Harri Vasander. Männyn kasvu ja uudistuminen luonnontilaisella ja ojitetulla sekä lannoitetulla keidasrämeellä.
English title: Growth and regeneration of scots pine (Pinus sylvestris L.) on virgin, drained and fertilized raised bog sites in Lammi, Southern Finland.
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The effect of draining and fertilization on the radial and height growth of Scots pine has been studied on an ombrotrophic bog Laaviosuo in the vicinity of Lammi Biological Station. The study site represents a southern Finnish raised bog with Calluna vulgaris — Empetrum nigrum — Sphagnum fuscum -hummocks and Eriophorum vagi-natum — Sphagnum angustifolium or Sphagnum majus — S. balticum -hollows. Total thickness of the peat layer is 5—7 m with a 2—3 m of Sphagnum peat on the surface. Part of the bog (6 ha) was drained in 1966 and fertilized in 1970 (N as urea 100 kg/ha plus PK fertilizer 400 kg/ha). This study is part of a project concerning the comparative analysis of virgin and forest-improved mire ecosystems (Ruuhijärvi et al. 1979). Height growth of pines during 15 last years was measured with the accuracy of 1 cm from 37 trees in the virgin site, 23 trees in the site with only drainage and 27 trees in the drained and fertilized site during the autumns 1978 and 1979. In addition seven trees from a virgin dwarf shrub pine bog near the marginal slope of Laaviosuo were measured for comparison in the autumn 1978. Radial growth was measured in 1979 from 17, 10, 10 and 7 trees, respectively, with the accuracy of 0.01 mm. All the measured trees were selected randomly. At the same time we counted all the trees and seedlings from a sample area both in the virgin and fertilized sites. In the virgin bog the size of the sample area was 1.92 ha and in the fertilized area 1.60 ha for trees and 0.88 ha for seedlings. Height of all seedlings was measured with the accuracy of 10 cm and breast height diameter (d1.3) of trees with the accuracy of 1 cm. Growth of trees in the virgin bog site was very low: height growth about 3 cm and radial growth: 0.2 mm annually (Fig. 1, 2). In dwarf shrub pine bog the corresponding values were about 9 cm and 0.6 mm. Mere draining had very little effect (about 1 cm) on the height growth (Fig. 1.). Radial growth increased more clearly (Fig. 2). However, the figures exaggerate the situation because the trees have been measured very near the ditches (about 1—8 m). Trees which have grown at a distance of less than about 3 m from the ditches have incresed their radial growth, but others growing further away have not. This increases the variation as seen in Fig. 2. In practise, if this kind of ombrotrophic bog is drained fertilization with all macro-nutrient (N, P, K) is needed. Effect of fertilization is very similar on radial and height growth with the difference that height growth always reacts one year later (Fig. 1, 2). Maximum growth (about 35 cm and 3.2 mm) was reached in 1973 and 1974, respectively, after which the growth decreased almost as quickly as it had increased. In ombrotrophic sites the effect of fertilization is known to last less than ten years (Huikari & Paavilainen 1972 and Ipatiev & Paavilainen 1975). Only refertilization could possibly secure the continuing of tree growth. Fertilizing has changed also the size-classes of trees and seedlings (Fig. 5,6). Number of trees has increased from 470 per ha in the virgin area to 1390 per ha in the drained and fertilized area. The tree volume increment has been six-fold (from 1.3 to 8 m3/ha). Number of pine seedlings increased from 7100 per ha to 15300 per ha. There were also 2060 birch seedlings per ha in the fertilized area. Especially hollows have become stocked with seedlings. All these seedlings must compete with dense shrub layer for the nutrients but its effect on the mortality of seedlings can not yet be known. Mere draining seemed to have no effect on the population structure of seedlings. The present volume of the pine stand in the fertilized area, 8 m3/ha on average, is of the same magnitude as Heikurainens (1971) average values for virgin cottongrass pine bogs. However, drainage of cotton-grass pine bogs and Sphagnum fuscum pine bogs with so scarce pine stands seems to be economically questionable (Heikurainen 1973). Thus according to our results, even after the drainage and NPK fertilization the tree stand of this site type is still so low that the drainage and fertilization of such ombrotrophic pine bogs is probably unprofitable.
  • Lindholm, Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Vasander, Sähköposti: ei.tietoa@nn.oo
Marjut Karsisto. Maanparannustoimenpiteiden vaikutuksista orgaanista ainetta hajottavien mikrobien aktiivisuuteen suometsissä. Osa II. Tuhkalannoituksen vaikutus.
English title: Effect of forest improvement measures on activity of organic matter decomposing micro-organisms in forested peatlands. Part II. Effect of ash fertilization.
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The results obtained from old ash fertilization experiments established in Finland in the 1930's have shown that wood ash is ideally suited for forest fertilization. The aim of this study is to determine the changes which have taken place in the microbial population and decomposition of organic-matter in the peat of old ash fertilization plots. The area of Tohmajärvi, where the ash fertilization experiment was established in 1939, completely lacked tree cover at the time of fertilization. The total production of the tree stand which has developed since fertilization is about 300 m3/ha. The oldest ash fertilization experiment in the Nordic countries is located in Sweden. The total production of the tree stand growing in the Norra Hällmyren area (fertilized 1926) was about 200 m3/ha until the year 1973 (Holmen 1979). The annual growth of the tree stand on the corresponding unfertilized areas is below 1 m3/ha. The results of chemical analyses carried out on the peat from Tohmajärvi are shown in Table 1. The ash fertilization has decreased the acidity by such a small amount only that this alone could not account for the good growth rate of the trees. The total amount of nitrogen has decreased in the surface layer of the peat in the plots which have got ash fertilization. This indicates that ash fertilization has brought about the conversion of nitrogenous compounds in the peat into a form that can be utilized by the plants. Organic matter decomposition at Tohmajärvi has been studied by observing the decomposition of cellulose strips placed at different depths in the peat (Fig. 2). Decomposition was more effective at a depth of 40—50 cm on the fertilized plots than at a depth of 5—10 cm on the unfertilized plot. Bacterial determinations were carried out on peat samples taken from Tohmajärvi on the 9th August 1977. The results are shown in Fig. 4. The numbers of different types of bacteria at all depths studied were many times greater on the plot given ash fertilization than at corresponding depths in the unfertilized plot. Ash fertilization has had the clearest effect on the number of bacteria in the 10—20 cm deep peat layer. Bacterial determinations were carried out on samples taken from the Hällmyren ash fertilization plots on the 23rd August 1979. The results are presented in Fig. 5. Ash fertilization has had an increasing effect on the number of bacteria only in the 0—10 cm surface layer. The numbers of different types of bacteria decrease very steeply on passing deeper down into the peat. Ash fertilization has increased the pH in the Hällmyren peat by one pH unit, but only in the 0—10 cm surface layer. Both tree growth in Tohmajärvi and Hällmyren areas and the microbiological analyses which were carried out show that ash fertilization brings about a permanent ameliorative effect. In the study areas where ash fertilization is already over 30 and 40 years-old, tree growth is still good and the numbers of different types of bacteria higher than in the unfertilized plots. However, the tree growth in the Hällmyren area is not as good as that at Tohmajärvi. This may be due to the fact that the natural nutrient status at Hällmyren is not as good as at Tohmajärvi and drainage is clearly less effective. It should be born in mind that if ash is to be used for forest fertilization, then efficient drainage is also neccessary.
  • Karsisto, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Pekka Pietiläinen, Heikki Veijalainen. Koe hivenlannoitteiden vaikutuksesta rimpisuon metsityksessä.
English title: Effect of some micronutrient fertilizers on the height growth of pine seedlings in a flark.
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Different kinds of boron and copper fertilizers were applied to pine seedlings planted in a flark (see table 1). Three growth periods after the fertilization copper oxide, fertilizer boron, fritted boron, micro-nutrient mixture and bark ash gave better height growth than the control (NPK, Ca). Poorest results were achieved with the following micronutrients; solubor, copper sulfate, copper chelate and PK with Cu and B. The height growth in years 1978 and 1979 of only those seedlings that were fertilized with solubor was poorer than that of the control. The height growtht of fritted boron and bark ash fertilized seedlings was statisticaly significantly better than that of the control. The best result was achieved with copper oxide (Table 2). The comparison between the copper fertilizers revealed that copper oxide was the best copper compound for pine seedlings in a flark (Fig. 1). Fritted boron appeared to be the best boron fertilizer (Fig. 2). Bark ash was best of the nutrient mixtures studied (Fig. 3). The experiment showed a positive trend in favor of slowly dissolving micronutrient compounds, including bark ash, on pine seedling growth in a flark. It is also evident, that the commercial micronutrient fertilizers are by no means biologically the most effective compounds for pine seedling fertilization on peatland. In forestry and research commonly used coppersulfate and fertilizer boron seemed to be rather questionable as peatland fertilizers.
  • Pietiläinen, Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Veijalainen, Sähköposti: ei.tietoa@nn.oo
Jouni Tummavuori, Hannu Venäläinen, Timo Nyrönen. Termogravimetrian käyttömahdollisuudet polttoainetutkimuksissa. Osa V. Polttoaineiksi soveltuvien materiaalien pyrolyysin kinetiikasta.
English title: The usability of the thermogravimetry in fuel research. Part V. On the kinetics of the pyrolysis of materials suitable for fuel.
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This work completes our previous thermo-gravimetric investigations of domestic solid fuels. In this part, we have mainly concentrated on the pyrolysis of less common fuels e.g. straw, stumps and rejected, old railway sleepers. These cannot, of course, be regarded as significant fuel sources but locally and we wanted to show that the kinetics of their pyrolysis shows no exceptional behaviour as compared with previous materials. Two peat samples were investigated because they differ from the other peat samples by their kinetic properties. The straw ash, however, has a surprisingly low melting point, which can be detected from the TG-curves. The utilization of used railway sleepers needs additional investigations, because the impregnating substances seem to evaporate in the course from the beginning to the end of the combustion. The safe use of the railway sleepers provides the determination of the toxicity of these substances.
  • Tummavuori, Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Venäläinen, Sähköposti: ei.tietoa@nn.oo
  • Nyrönen, Sähköposti: ei.tietoa@nn.oo
Dan Asplund, Kari Salo. Polttokaasun valmistus turpeesta.
English title: Production of fuel gas from peat.
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Gasification was studied at the Technical Research Centre of Finland in the 1950s. After the era of cheap oil, the research work on the gasification of domestic solid fuels was restarted in the fall of 1975. In a technico-economic study it was concluded that the most favourable short-term application alternatives were processes with sod peat or peat pellets as raw material and low-Btu fuel gas as products. The energy price of gas was calculated to be between those of light and heavy fuel oil so that in the size class of 10 MW and at a high efficiency of use the price of heavy fuel oil is approached in fixed bed gasification. Gasification tests were carried out on a co-current fixed bed reactor. It was found that peat with 50 % moisture content and with about 30 % content of fine material is suitable for gasification. The amount of gas generated per kg peat dry matter was 2.8 to 3.2 m3n. The chemical efficiency was about 70 % at its best. The total efficiency is considerably increas-ed if the sensible heat of gas can be utilized. Tests with fluidized bed gasification were also restarted in the Fuel and Lubricant Reserach Laboratory of the Technical Research Centre of Finland both on the PDU and pilot plant scale. For the time being, tests with the production of activated carbon from peat coke have been carried out on the pilot plant equipment, while the equipment will be modified after the PDU tests for the use in gasification tests. Fluidized bed gasification is an alternative of consideration when peat is gasified on a large scale. The production of both fuel and synthesis gas can be considered. The development of fluidized bed gasification on the basis of the peat combustion systems in fluidized bed is considered possible and necessary.
  • Asplund, Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Salo, Sähköposti: ei.tietoa@nn.oo
Marjut Karsisto. Maanparannustoimenpiteiden vaikutuksista orgaanista ainetta hajottavien mikrobien aktiivisuuteen suometsissä. Osa I. Pohjaveden etäisyyden ja NPK-lannoituksen vaikutus Vilppulan ja Kivalon rämeellä ja korvessa.
English title: Effect of forest improvement measures on activity of organic matter decomposing micro-organisms in forested peatlands. Part I. Effect of drainage and NPK fertilization in the spruce and pine swamps at Kivalo and Vilppula.
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The aime of the study is to determine whether the decomposition of organic matter and the activity of different groups of micro-organisms has changed in peat-lands where the ground-water table has been maintained at different depths for a considerable length of time. The study has been carried out in sample plots situated on Scots pine and Norway spruce swamps where the groundwater table has been maintained at depths of 10, 30 and 70 cm since 1960. The annual growth of the trees has been followed since the time when the experiment was established. It has thus been possible to examine the connection between tree growth and the numbers of different types of bacteria and the rate of decomposition of the organic matter. Experiments with NPK fertilizer were established in 1961—1962 on plots where corresponding ground-water table regulation had been carried out. The plots in North Finland were refertilized in 1965, and those further to the south in 1967—1969. Intensification of drainage on the sample plots established on spruce swamps has produced a considerable increase in stand growth (Fig. 1). Decomposition of cellulose in the peat has also increased (Fig. 2). Cellulose decomposition on the plots which have been efficiently drained is effective down to a depth of at least 50 cm. Fertilization increased stand growth most on those plots on the spruce swamp where the ground-water table had been maintained at a depth of 10 cm from the surface. Cellulose decomposition also became more effective on these plots. The nutrient reserves in peat which has been efficiently drained, have possibly been sufficient without any fertilizer addition. Fertilization has had a strong effect on stand growth on the pine swamps, the best results being obtained with a drainage depth of 30 cm. Fertilization has also had the strongest effect on cellulose decomposition in the plots on pine swamps where the ground-water table has been maintained at a depth of 30 cm. The numbers of aerobic, ammonification and proteolytic bacteria in the surface layer of the unfertilized peat have been the greater, the deeper the ground-water table (Fig. 5). Intensifying drainage has had the strongest effect on the number of ammonification bacteria. Fertilization, similarly, had the strongest effect on the number of ammonification bacteria. In other words, the activity of both the trees and the bacteria has been limited by a lack of nutrients, which fertilization has alleviated. Although drainage makes the conditions in the peat more aerobic, the number of anaerobic, bacteria has not decreased as the efficiency of drainage increased. Generally speaking, the higher the level of bacterial activity, the better the tree growth. Following changes in the number of different types of bacteria provides information about the decomposition of organic matter in the peat. However, this is not sufficient and chemical analyses are also required.
  • Karsisto, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Jussi Ranta. Turpeen maatumisasteen ja termoanalyyttisen informaation vertailu.
English title: A comparison between the decomposition degree of peat and thermoanalytical information.
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In the study, comparisons were made between the decomposition degree of peat deternimed in accordance with GOST-10650-72 standard, and DTG peaks for peat. When a peat sample of 15 mg and a heating rate of 10°C/min were used, peaks were observed in temperature areas of 310 to 325°C and 415 to 435°C. The former area presents the oxidation of sugars and cellulosic material. The height of the peak correlates with the degree of decomposition, the correlation coefficient being —0,92 (n=10). When the decomposition values were compared with the height of the peak in the area of 415 to 435°C, a value of 0,73 was obtained for the correlation coefficient. When the ratio of the peak heights was compared with the decomposition degree, a value of —0,94 was obtained. Hence- the decomposition degree of peat can be determined fairly reliably by aid of thermogravimetric measurements, if the contents of thermal changes are known adequately accurately.
  • Ranta, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Eero Pelkonen. Männyn ja kuusen taimien kyvystä sietää tulvaa vuoden eri aikoina.
English title: Seasonal flood tolerance of Scots pine and Norway spruce seedlings.
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The root systems of rooted Scots pine and Norway spruce seedlings were kept in slow-flowing or stagnant ditch water for periods of varying length during different seasons. In the snowless period, the "flood" lasted from one week to three months. The seedlings were planted immediately after they hade been removed from water. If the treatment was started early in the spring before the beginning of root activity, both pine and spruce seedlings survived even if the treatment lasted until beginning of August. However, slight negative effects in growth and general development were observed. During late summer and autumn, pine and spruce seedlings appeared to suffer much more of temporary "flooding"" treatments than in spring and early summer. A treatment period of 2—3 weeks often was detrimental to a seedling. Norway spruce seedlings were less resistent in this respect than Scots pine seedlings. In November when soil temperature is approaching 0°C in Southern Finland, artificial flooding still caused damage to spruce seedlings. Part of the seedlings included in the experiments were kept in water throughout the winter. The effect of the treatment on the seedlings depended on the degree of ice formation in the water reservoir. If only a thin ice cover was formed (slow-flowing water), leaving major part of the root system in liquid water, both pine and spruce seedlings survived quite well; only a slight decrease in growth was observed during the following growth period. Instead, if the whole root system was surrounded by solid ice (stagnant water), more negative influences were observed, especially in the case of Scots pine. Also in the case of Norway spruce, a considerable decrease in growth during the next growing season was detected. Analogous experi-mets with larger individuals of the same two species (Pelkonen 1975, 1976 have shown corresponding results. "
  • Pelkonen, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Eero E. Heino. Uutta teknologiaa metsäojitusalueiden hoitotarpeiden selvittämisessä.
English title: New technology for inventories of drained peatland forests.
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  • Heino, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Jukka Laine. Kontortamännyn alkukehitys ojitetulla karulla avosuolla.
English title: Initial development of Pinus contorta on a nutrient poor open bog in Finland.
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The paper gives preliminary results of the initial development of lodgepole pine (P. contorta var. latifolia, provenance: Wono-won, British Columbia, Canada, 56°10'N; 121°30'W; 800—1000 m above sea level), compared with that of native Scots pine (P. sylvestris) in a planting experiment on a drained small-sedge bog nine years after planting in 1969. The experimental field is situated in Central Finland (61°50'N; 24°14'E; about 165 m above sea level). The annual rainfall is about 600 mm and that of the summer months (June-September) about 280 mm. Annual evapotranspiration is approximately 300 mm. The experimental field is divided into three areas (blocks), in which different drainage systems (ditch types) were used. In each area there are 8 sample plots, with 300 transplants in each, making a total of 24 plots and 7200 transplants of both pine species in the experiment. Area A is drained using ordinary open ditches, area B using plastic pipe drains and area C using narrow, vertical-walled ditches. Hyd-rological measurements were carried out in the areas in the years 1968—72 and the results have been previously published by Päivänen (1976). According to the results it was found out that the drainage effect of the plastic pipe drains was clearly smaller than that of the other ditch types, i.e. the water table in area B remained some 10 cm nearer the peat surface than in the two other areas. This affected the growth of the transplants so that the growth rate of both tree species studied, especially that of Scots pine, was in area B clearly slower (statistically significantly) than in areas A and C (Fig. 1). The height development of Pinus contorta during the first nine years since planting clearly exceeded that of P. sylvestris, except for area C (deep, narrow, vertical-walled ditches and seemingly slight-ly better nutrient status, because the amount of Sphagnum fuscum hummocks in this area was smaller) where Scots pine grew significantly better than in other areas (Fig. 1, Table 1). Lodgepole pine was 9 years after planting, on the average, in area A 31 %, in area B 24 % and in area C 5 % taller than Scots pine. This is in accordance with the results obtained in other studies with similar provenances (Hahl 1978). The mortality of transplants was also inventoried in summer 1978. The mortality of lodgepole pine turned out to be signi-ficantly smaller than that of Scots pine in all areas (Table 2). The proportion of dead Scots pine transplants was significantly higher in the poorly drained area B than in other areas, whereas Pinus contorta does not seem as susceptible to poor drainage. A new planting of both pine species took place in spring 1977 with the same experimental design and the mortality was inventoried in summer 1978. Table 2 shows that dying-off has been very small in both species confirming the results of the earlier planting (data group a in Table 2). The mortality of Pinus sylvestris was significantly bigger also in the latter planting (data group b in Table 2). The results of this experiment show that the early growth of suitable Pinus contorta provenances is somewhat better than that of Pinus sylvestris also in peatlands at least in circumstances described in this paper. It is also indicated (Fig. 1) that the requirements of lodgepole pine for drainage and nutrients may be smaller than those of Scots pine in peatlands.
  • Laine, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Juha Menonen, Juhani Päivänen. Polttoturvesuon lisäkuivatus salaojituksella.
English title: Additional drainage with subsurface drains in a milled peat harvesting site.
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The layout of a drainage system for a milled peat harvesting site is seen in Fig. 1. The ditch spacing used is 20 m and the ditches are about 1.5 m deep. However, sometimes it is necessary to use subsurface drains to increase the drainage effect of open ditches. In the rick areas at the end of the strips, where the harvested peat is stored, subsurface drains are the only method to drain the peatlayers. Eight different kinds of subsurface drains were tested in summer 1978 at Kaikonsuo (63°40'N, 26°40'E) peat harvesting field managed by The State Fuel Centre (VAPO). Two experimental fields were laid down: one in the strip area (Fig. 2) and the other in the rick area (Fig. 3). Five of the subsurface drain types used in the experiment were so called material drains: a board pipe drain with an inner cross-section of 64x102 mm (Fig. 8), and two sizes of plastic pipe drains (PVC) with an inner diameter of 40 and 65 mm. Two types of both drainsizes were used, one of which was bare (Fig. 9) the other covered with a filter material (Fibertix; Fig. 10). Three types of "nonmaterial" subsurface drains were tested in the experiment: a mole drain made with the Pajulahti Oy mole drain trencher (Fig. 4 and 5), a mole drain made with the VAPO mole drain plow (Fig. 6), and a narrow water furrow made with the Suokone Oy disc trencher. The ground water level in each drainage treatment was measured once a week. In the strip area, in each treatment, there were measuring wells in two rows; five in a row. In the rick area there were five wells in each treatment. In the strip area (Fig. 11) the distance to the ground water level in the control strips was about 50 cm. The mole drains or the narrow water furrows did not have any effect on the ground water level. The board pipe drains had the greatest lowering effect on the ground water level. In the strips with the plastic pipe drains the distance to the ground water level was about 80 cm. In the rick area the results obtained with the board pipe drain, with the mole drains and those of the control were similar to the results of the strip area. In the treatments drained with the plastic pipe drains the distance to the ground water level varied from 55 to 95 cm. The filter material did not increase the drainage effect of the pipe drains as expected, the case was rather the reverse. It would be necessary to continue the experiment to find out the duration of the drainage effect reached with the different kinds of subsurface drains and, after that, to make economical calculations on the profitability of the types of subsurface drainage studied.
  • Menonen, Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Päivänen, Sähköposti: ei.tietoa@nn.oo
Tapio Lindholm. Keidasrämeen mätässammalten vuotuinen pituuskasvu Lammilla EH.
English title: Annual height growth of some hummock mosses in Southern Häme.
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The annual height growth of three hummock moss species was studied in two neighbouring ombrotrophic raised bogs in Lammi commune, southern Finland (N 61° 02', E 24° 58'). The species were the dominant species of the hummocks: Sphagnum fuscum, Polytrichum strictum and Sphagnum rubellum. The annual increment was measured backwards for seven years (Figs. 1—3) by the "innate markers" occuring of the cyclical patterns of the growth (Maimer 1962, Pakarinen & Tolonen 1977). The samples were taken from c. 30 different places in different parts of the bogs. The mean height growth was 10.8±l.5 SD/a in Polytrichum strictum, 11.6 mm ±0.9 SD/a in Sphagnum fuscum, and 10.9 mm ±l.l SD/a in Sphagnum rubellum. The annual variation was quite small, whereas the variation between microhabitats was great. In high hummocks the growth of P. strictum and S. rubellum seems to diminish by years due to increasing distance to the water table. S. fuscum seems to be more tolerant against drier conditions. It also grows slightly better than the other two species. This may be the reason why S. fuscum is the dominant species on Finnish raised bog hummocks. The "innate marker"" method does not allow measurements of the annual increment if the moss shoot growth is very slow in the hummock and thus may give slightly too high growth estimates. Similar values of annual increment of hummock peat have been observed also in other studies (Borggreve 1889, Saarinen 1933, Hornets 1974, Pakarinen 1978). The annual variation in the growth was not investigated in the earlier studies, where results are mainly means of many years' growth. It is obvious that in ombrotrophic raised bogs the hummock mosses cannot grow more than 10—12 mm/a in our environ-mental conditions. In other conditions, eg. in Great Britain (Clymo 1970), and also in better sites in Finland (author's own field observations) the annual growth rate can be much higher. "
  • Lindholm, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Risto Heikkilä. Kituvien suotaimistojen tuhonaiheuttajista Pohjois-Suomessa.
English title: On the damages noted in pine seedling stands established on peatlands in Northern Finland.
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The occurrence of different types of damaging agent in 9 Scots pine seedling stands established on peatlands and subsequent effect on the initial development of the seedlings was examined in the study. The results concern only those parts of the seedling stands, many of them rather extensive ones, which were in a poor condition. About 36 % of the seedlings had either died or were incapable of further development as a result of damage by various agents. The most commonly occurring insect pests were pine weevils (Pissodes spp., especially P. pint L.), damage being caused by both larvae (in seedlings weakened before) and imagos. Damage caused by Petrova resinella L. which makes grooves in the seedlings that remain unhealed for a long time, was found to some extent. Damage caused by Hylobius-species was very rare. Damage caused by Diprionidae and Cryptocephalus pini L. was found to some extent but it was very slight. Of the fungal deseases, pine stem canker (Scleroderris lagerbergii Gremmen) was found to be a serious damaging agent. Snow blight {Phacidium infestans Karst.) occurred relatively abundantly, but because most of the seedlings had already grown higher than the snow cover, the effect of this fungus was generally only slight. Stems damaged by pine stem rust (Melam-psora pinitorqua Rostr.) were found to some extent, the damage being only slight. Abiotic damage was rather common on the seedlings. Snow had broken branches and pressed the seedlings down, thus weakening them and making them more susceptible to subsequent damage. Rather a lot of the seedlings (22 % of them) were suffering from bark damage (channels, compression, drying out of the bark), which obviously often presupposed damage by pine stem canker and pine weevils. Needle yellowing, symptomatic of nutrient deficency, was also found in part of the areas. Most of the damage noted in this study was of the same kind as that found in Scots pine seedling stands established on mineral soils sites in Northern Finland.
  • Heikkilä, Sähköposti: ei.tietoa@nn.oo (sähköposti)
Jouni Tummavuori, Hannu Venäläinen, Timo Nyrönen. Termogravimetrian käyttömahdollisuudet polttoainetutkimuksissa. Osa IV. Paineen alentamisen vaikutus pyrolyysiin.
English title: The usability of the thermogravimetry in fuel research. Part IV. The effect of the reduced pressure on the pyrolysis.
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In this article we survey the pyrolysis of some solid domestic fuels in the lowered pressure, which completes the picture of the pyrolysis. Also, the possible comparison between the pyrolysis of the domestic fuels and the research methods have been rendered. The lowered pressure has a significant effect on the pyrolysis, because part of the polymerization and the coking are hindered. Up to the 650 K the pyrolysis seems to occur as in the nitrogen gas but thereafter no coking appears but the thermal decomposition proceeds. The remaining part of the reaction equals to the ash amount obtained after the reaction in the mixed gas. It is also obvious, that the particle size plays an important role in the pyrolysis in the lowered pressure. This can be seen from the inconsistent results presented in the literature. The substances under investigation are mixtures of several organic compounds whose composition or even an average molecular mass is unknown. The calculation methods employed here are based on the approximations which are valid for the simple reactions of the compounds with known structures. Their application to the unknown reactions is strongly criticized. If we perform the measurements in equal conditions and interprete the results as pseudo constants, they have, however, significance if the average properties of the pyrolysis of different substances are compared. Finally, since the pyrolysis of the organic matter completely occurs in the lowered pressure, this may have meaning when the refining processes are developed.
  • Tummavuori, Sähköposti: ei.tietoa@nn.oo (sähköposti)
  • Venäläinen, Sähköposti: ei.tietoa@nn.oo
  • Nyrönen, Sähköposti: ei.tietoa@nn.oo

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