Articles containing the keyword 'tilavuus'
Category : Article
Five ploughed research areas from Finnish Norther Karelia were selected for comparison studies of plough ridges and untouched soil. Measurements were made at a depth of 10 cm in sample plots on both mineral and paludified mineral soil and peatland parts of these areas. In summer 1987 daily soil water matric potential was measured using tensiometers, and volumetric soil moisture content and density were determined from soil samples at two dates during the summer. Water characteristics of the core samples were also determined. On paludified mineral and peat soils the water table depth from the soil surface was measured.
The results indicated that in plough ridges matric potential was lowest. Plough ridges were also seen to dry and wet faster and to a greater degree than untouched soils. In untouched soils, soil water relations and aeration were not affected by the distance to the furrow. The effect of the plough ridge was smallest on peatland, where there was a good capillary connection from plough ridge to the ground water, if the ditches were not very effective. The soil in the ridges did not dry too much to restrict seedling growth. The untouched surface soil in poorly drained peat and paludified minear soil was, at least in a rainy growing season, often and also for long times so wet that 10% minimum air space required for good seedling root growth was not available.
The PDF includes an abstract in English.
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Mannerkoski,
E-mail:
hm@mm.unknown
- Möttönen, E-mail: vm@mm.unknown
Gravimetrically expressed nutrient concentrations of soil analysis were converted to volumetric values using dry bulk densities measured in the natural state and in the laboratory after air-drying and sieving the samples. The aim was to examine, using volumetric samples representing different soil classes, exactly how the converted nutrient values calculated by this laboratory method describe volumetric nutrient contents in undisturbed soil. In the fine soil classes undisturbed bulk density was higher than laboratory bulk density and converted nutrient concentrations were too small. In coarser soil classes the reverse was true, and the values were too high.
The PDF includes an abstract in English.
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Niska,
E-mail:
kn@mm.unknown
A method for calculation of the effect of practical fertilization for economic evaluation is presented and discussed. 55 Norway spruce (Picea abies (L.) H. Karst.) dominated stands on Oxalis-Myrtillus type sites were surveyed five to eight years after fertilization with nitrogen (90-170 kg/ha). The relationships between the fertilization effect and various stand characteristics were discussed. Fertilization increased the growth of the stands on an average by 2.2 m3/ha/year. In total the increase of tree growth during the research period was 17.5 m3/ha. This corresponds to a yield of 525–659 FIM/ha.
The PDF includes a summary in English.
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Westman,
E-mail:
cw@mm.unknown
- Leikola, E-mail: ml@mm.unknown
- Nummi, E-mail: tn@mm.unknown
Early growth of four different tree species (Pinus sylvestris L., Picea abies (L.) H. Karst., Larix sibirica Ledeb and Betula pendula Roth) 16–23 years after planting were compared in a field experiment of 16 square plots established on a stony, grove-like upland (Oxalis-Myrtillus forest type) in Southern Finland. This study gives additional results to the publication Folia Forestalia 386/1979.
At this early stage, the growth of the spruce stand was clearly slower than that of the other species for all parameters to be measured (height, diameter, and volume growth). Height growth was most rapid in the silver birch stand and diameter growth in the larch stand. No clear differences were found in the mean volume of the 100 thickest trees in the stand between the larch and silver birch.
The PDF includes a summary in English.
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Parviainen,
E-mail:
jp@mm.unknown
In this study the loose volume of 58 piles of pulpwood were measured before and after barking by rotary ring barker. The volume was 2,121 m3. A recommendation is made, based on the results of the study, concerning the barking loss from piled wood: for green Scots pine (Pinus sylvestris L.) pulpwood, 8.8% of the stacked volume; for seasoned pine pulpwood, 6.1% of the stacked volume; and 8.0% for birch (Betula sp.) pulpwood, green and seasoned. The amount of bark left on bolts was small for pine bolts, namely 0.33%, but quite large for birch bolts, 2.84% of the green weight.
The PDF includes a summary in English.
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Kärkkäinen,
E-mail:
mk@mm.unknown
According to the available literature, the times when pulpwood limbing was made by axe and barking by hand tools, barking either had no effect on the pile density (if limbing quality was good) or increased pile density (if limbing was bad). When rotary barking machines are used, the branch stumps remain intact during barking. Therefore, if there are branch stumps in the pulpwood, barking decreases the pile density. Nowadays, when power saw limbing is a common practice in Finland, barking presumably greatly decreases the pile density, due to the fact that in power saw limbing branch stumps are numerous and high. Therefore, the method to estimate the solid volume of a pile of unbarked pulpwood are not applicable to barked pulpwood without modification.
The PDF includes a summary in English.
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Kärkkäinen,
E-mail:
mk@mm.unknown
In this paper the use of butt and top diameters of pulpwood bolts for volume determination is analysed. The study is based on the taper data of Scots pine (Pinus sylvestris L.) stems. According to the results, the use of the mean of butt and top diameters in the volume determination under Finnish condition causes a positive error in small stems. If the stems are so big that the butt portions of the stems can be used as saw logs, the remaining top bolts, used as pulpwood, are estimated to be smaller than they are in reality. Accordingly, there is a negative error.
The PDF includes a summary in English.
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Kärkkäinen,
E-mail:
mk@mm.unknown
The aim of this study was to estimate the genetic gain of volume growth in Scots pine (Pinus sylvestris L.) selected seed stands. To obtain highest possible accuracy, the estimations are based on a large statistical material comprising 197 separate seed stands. It is concluded that the genetic gain of volume growth ranges between 7.4–15.0%. Unwanted pollen contaminations may, however, in the worst case halve this genetic gain.
The PDF includes a summary in English.
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Oskarsson,
E-mail:
oo@mm.unknown
- Tigerstedt, E-mail: pt@mm.unknown
The present study gives an account of the dependence prevailing between the actual volume of timber crops, and, on one hand, the sum of cylindrical volume of individual trees, and on the other hand, the utilization per cent. This dependence is rectlinear if the volumes in question are calculated on a running-foot basis. The cylindrical volume of individual trees was calculated on the basis of cross-section area at breast height and the height of the trees. On the basis of the results, it seems that it is possible to simplify timber measurement.
The PDF includes a summary in English.
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Nisula,
E-mail:
pn@mm.unknown
The Forest Research Institute of Finland has established permanent sample plots to survey the effect of thinnings on the stands. This study compares the development of tended and natural Scots pine (Pinus sylvestris L.) stands growing on three different forest types: Oxalis-Myrtillus, Vaccinium and Calluna site type. The effect of heavy thinning from below (Oxalis-Myrtillus and Vaccinium site types) and increment felling (Calluna site type) was assessed by dividing the trees of the stands in tree classification classes according to their crown storey and defects.
The results show that thinning from below and increment thinning increase the proportion of trees in the 1st crown storey, which is already large in the natural stands. Also the diameter distribution is more even and the mean diameter higher after the thinnings.
In Scots pine stands in natural state, volume increment per stem is highest in the 1st crown storey and diminishes strongly towards the lower crown storeys. Thinnings increased the increment. The study indicates that many of the objectives of the intermediate cuttings, including promoting the growth of the best trees and improving the quality of the stand, have in general been achieved. Consequently, the thinnings give means to achieve the most valuable yield in the stand.
The article includes a summary in English.
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Nyyssönen,
E-mail:
an@mm.unknown
Category : Article
In Finland ocular estimation of the growing stock has been made by means of volume tables based on the mean height and density class, or on the dominant height and density class of the stand. The author has observed that if the volume of a stand is estimated by employment of both tables, the results vary markedly from one another. Furthermore, volume of fully stocked stands in the dominant height tables show an approximate correspondence with the volumes of managed normal stands in Southern Finland.
The purpose of this study is therefore to develop volume tables for coniferous trees, based on the density class and the mean height; these tables should give the same volume for a stand as the dominant height tables.
Volume per hectare of 187 Scots pine (Pinus sylvestris L.) stands and 120 Norway spruce (Picea abies (L.) Karst.) stands on different forest types were estimated using the relascope method in Southern Finland. With the volume and the measured mean and dominant heights as a basis, the density classes were extracted from both mean height tables and the dominant height tables. The investigation indicates that the author estimated the dense stands too thinly, and the thin ones too densely, and that the erroneous estimation of the density can be corrected by comparison of the ocular estimations and the corresponding measurements. The density can be measured by means of crown closure, stem number per hectare or the basal area per hectare.
The PDF includes a summary in English.
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Kallio,
E-mail:
kk@mm.unknown
In this investigation was studied 1) Volume growth and yield of timber in managed Norway spruce (Picea abies (L.) Karst.) forests under different rotations. 2) Value growth, net forest income and soil expectation value of managed forests under different rotations, and 3) The rotations of spruce forests managed on different rotation principles. The data was collected from Oxalis-Myrtillus type forests in South-West Finland.
Two developmental series of stands were constructed for the research, one of which were of better sites than the other. Sample plots were pure, even-aged spruce stands in well-managed forests. The stands had been thinned from below. The age varied from 25-30 years to the age of final cutting.
According to the study, in the artificially regenerated spruce stands the highest mean annual volume growth, 9.7 m3/ha, and also the highest net annual income of 14,50 Finnish marks/ha (calculated from average stumpages) was reached in rotation of 70 years. In the other managed spruce forests a mean annual volume growth of 6.6-8.8 m3/ha and the net annual income of 10,500-14,500 Finnish marks/ha were reached in the rotation of 70-100 years. The rotation for the maximum mean annual volume growth varied in the different series between 67-92 years. The maximum mean annual forest rent was only achieved in series B in a rotation of about 100 years, and in a naturally normal stand in a rotation of about 120 years. The intensity of thinnings and silviculture had a greater effect on value growth and on net income than on volume growth.
The PDF includes a summary in English.
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Kallio,
E-mail:
kk@mm.unknown
The study examines the accuracy of volume tables for top measurement of pulpwood boles, and that of top measurement in general in Northern Finland. In this method only top diameter and length of the boles are measured, and the volume is obtained from volume tables. The boles have previously been measured in the middle of the bole, but the method is very time consuming in practice.
The result indicates that the form of both Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) varies greatly. A pulpwood parcel, however, contains both rapidly and gently tapering logs, and the average form differences are much smaller. The difference between the real volume and the volume obtained from the volume tables is generally less than 12% and for more than third of the stock less than 4%.
Pine boles from private forests have been somewhat more and spruce boles less rapidly tapering than boles cut from state forests. The significance of the differences is not clear. Also, the boles in the northern part of the investigation area taper more sharply than those in the southern part.
It is concluded that the accuracy of the top measurement should be improved, but this is only theoretically possible by means of special tables and correction coefficients.
The Acta Forestalia Fennica issue 61 was published in honour of professor Eino Saari’s 60th birthday.
The PDF includes a summary in English.
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Heiskanen,
E-mail:
vh@mm.unknown
Sample trees of Betula sp. were felled in North Karelia in different forest site types. The stands, both mixed and pure stands, had been regenerated in areas where shifting cultivation had been practiced. Sample trees represented breast height diameters up to 43 cm. Diameter was measured in distances of 1/10 of the height of the tree to calculate the stem form. The form factor was higher for the good forest site types than the poor sites. The volume tables were calculated based on the assumption that diameter does not affect the form factor. Comparing the volume table to the original data, it was found that the table seems to form a successful fitting of the data. Control data proved that the method seems to give a good fitting to the used data. Thus, the volume table can be used to measure volume of birch stands in North Karelia.
The PDF includes a summary in German.
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Hildén,
E-mail:
nh@mm.unknown
Tree growth is one of the factors that have been used to determine the site quality. The aim of the study was to show that growth of single trees growing on a same forest site class are similar, but differ from trees growing on a different site type. To compare the tree growth, a stem analysis was performed to dominant trees in Scots pine (Pinus sylvestris L.) stands, measured in 15 Myrtillus type sample plots and in 15 Calluna type sample plots in state forests in Salmi, situated in north side of Lake Ladoga. The height growth when the tree was young was higher in the trees growing in the Myrtillus type than in the Calluna type. Also, the trees of same age are higher in Myrtillus type stand than in the Calluna type. In Calluna type, the height growth, however, evens out later in age than in the Myrtillus type. The volume growth of the trees begins to increase earlier in Myrtillus type, and is higher than in Calluna type. Similarly, the diameter growth in breast height is higher in the Myrtillus type.
The PDF includes a summary in German.
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Ilvessalo,
E-mail:
yi@mm.unknown
The aim of this investigation was to examine the dependence of stand volume and increment on different growth factors on drained peatlands drained 20 years ago. Measurements were made in 1977-79 on 35 sample plots in Central Finland on relatively poor pine bogs with a thick peat layer.
It became evident that the stand volume, increment and radial growth and growth development are primarily functions of groundwater depth. Groundwater depth is dependent, in the first place, on ditch depth and ditch condition. With regard to the variation in ditch spacing (ca. 35-70 m) under examination, the effect of ditch spacing on the stand was insignificant. As a practical recommendation it was concluded that ditches should be kept deep enough (> 70 cm) in order to maintain undisturbed stand development.
The PDF includes a summary in English.
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Heikurainen,
E-mail:
lh@mm.unknown
The paper concerns the estimation of the increment of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) stands in the southern half of Finland. For the methods based on stand tables, tree functions forecasting the annual increment of diameter and height during the next 5-year period are presented. The main results of the study, however, are the functions for the volume increment percentage of pine and spruce stands. The independent variables are: forest site type, tree species, stand age and volume, and mean diameter. The standard error of estimate is about 17% in the best functions. Calculations were made also with regard to the application of the results in growth estimation of large forest areas.
The PDF includes a summary in English.
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Nyyssönen,
E-mail:
an@mm.unknown
- Mielikäinen, E-mail: km@mm.unknown
This study is concerned with silvicultural selection from above. The material consists of 18 Scots pine (Pinus sylvestris L.) sample plots in the southern half of Finland in experimental forests. The method is motivated by the great difference between the stumpage prices of saw timber and pulpwood. The method suggested includes the removal of individuals belonging to the predominating canopy, to achieve high levels of income from the stand at an early stage. The method is applied at when the growing stock is attaining saw-timber size. Before that the stand is treated with thinnings from below. It is supposed that the volume of growing stock is maintained at a level as high as that in below-thinned stands, and that rotation is of normal length.
On the average, the increment in basal area, as well as volume increment, is greater in stands selectively cut from above than in those treated with low thinnings of the same degree. Initially, selection from above seems to exert a negative effect upon the development of dominant height; later, the dominant height reassumes the same rate of increment as in the below-thinned stands. Selection from above also means an increase in saw-timber production, although it involves a reduction in the mean size of saw timber. The investigation includes growth and yield tables for pine stands treated with silvicultural selection from above.
The results of the investigation prove that silvicultural selection from above is at least as profitable as low thinning. This provides freedom for stand treatment, and contributes to the application of a method most suitable for the owner in each individual case. It is further stressed that the maintenance of a high wood capital in the stand is far more important than the method of thinning applied.
The PDF includes a summary in English.
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Vuokila,
E-mail:
yv@mm.unknown
