Articles containing the keyword 'yield'

A gap-model was used with forest inventory data in taking ground-true site, soil and tree characteristics into account in predicting the effects of climate change on forests. A total of 910 permanent sample plots established in the course of national forest inventory (NFI) in Finland and located on mineral soil sites in southern Finland were selected as the input data. The climatological input used in the simulations consisted of interpolated means of and deviations from long-term local temperature and precipitation records. The policy-oriented climate scenarios of SILMU (Finnish Research Programme on Climate Change) were used to describe the climate change. The temperature changes in the climate scenarios were increases of ca. +1.1 °C (low), +4.4 °C (medium) and +6.6 °C (high) compared to the current climate in 110 years. The simulation period was 110 years covering the time years 1990–2100.

Southern Finland, divided into fifteen forestry board districts, was used as the study region. Regional development of stand volume, cutting yield, and total wood production of forests under different climate scenarios were examined. The annual average growth in simulations under current climate was close to that observed in NFL Forests benefited from a modest temperature increase (Scenario 2), but under Scenario 1 the growing stock remained at a lower level than under the current climate in all parts of the study region. In wood production and cutting yield there were regional differences. In the southern part of the study regional wood production under Scenario 1 was ca. 10% lower than under the current climate, but in the eastern and western parts wood production was 5–15% higher under Scenario 1 than under the current climate. The relative values of total wood production and cutting yield indicated that the response of forests to climate change varied by geographical location and the magnitude of climate change. This may be a consequence of not just varying climatic (e.g. temperature and precipitation) and site conditions, but of varying responses by different kind of forests (e.g. forests differing in tree species composition and age).

• Talkkari, E-mail: at@mm.unknown

Yield of Cupressus lusitanica Mill. was modelled by predicting the diameter distribution of trees at given stand ages. The beta distribution was used as a theoretical distribution. The models used for the calculation of diameter distribution were based on 66 temporal sample plots with varying age, site and stand density. The growing sites of Cupressus lusitanica were divided into four classes on the basis of age and dominant height. Using the stand models developed in the study, the yield and profitability of different thinning schedules was evaluated by a simulation technique. In the simulated treatment regimes, the mean annual increment varied from 6.6 m³/ha in the poorest site class to 16.6 m³/ha in the best class with rotation lengths ranging from 25 years (best sites) to 34 years (poorest sites). With typical planting densities (1,600 trees/ha), thinnings increase the total harvest by a few percentage points and improved the profitability of plantation forestry.
The PDF includes an abstract in Finnish.

• Pohjonen, E-mail: vp@mm.unknown
• Pukkala, E-mail: tp@mm.unknown

Three Scots pine (Pinus sylvestris L.) plantations carrying 35 plots with initial spacings from 800 to 5,000 plants/ha were studied. Planting designs varied from a square to a rectangle with 5-metre row distance, the plant-to-plant distance being 0.8 metres. At current dominant height of 6 m, rectangularity had no effect on height, diameter, or volume growth of trees. Slight ovality of stems was observed in rectangular plots but the differences in the cross-wise mean diameters were very small, not over 1.1 mm in terms of plot-wise means. The diameter of the thickest living branch of a tree was linearly dependent of the dbh. The branches were clearly thicker between the planting rows at under 1,600 stems/ha stand density. A non-square planting pattern is a conceivable alternative when the line corridors suitable for mechanized silvicultural operations are preferred.
The PDF includes an abstract in Finnish.

• Salminen, E-mail: hs@mm.unknown
• Varmola, E-mail: mv@mm.unknown

The paper presents a simple model of long-term forest management planning in tree plantations. The model is particularly suitable for developing countries where the research resources are limited. The management plan is prepared in two steps. First, one or several treatment schedules are simulated for each calculation unit (age class, compartment, etc.) over the selected planning period. Second, an optimal combination treatment schedules according to the selected objectives and constraints is searched by mathematical programming. The simulation of growth is based on the prediction of the diameter distribution at the desired time point. All stand characteristics are derived from this distribution. The models needed in the yield simulation can be estimated from temporary sample plots. A case study management plan for 13,000 ha of Pinus kesiya (Royle ex Gordon) plantations in Zambia is presented to demonstrate the system.

The PDF includes an abstract in Finnish.

• Pukkala, E-mail: tp@mm.unknown
• Mubita, E-mail: om@mm.unknown
• Saramäki, E-mail: js@mm.unknown

The purpose of the study was to determine the effects of the origin of seeds and the location of cultivation of Scots pine (Pinus sylvestris L.) on certain properties particularly important to the pulp industry. The research material consisted of six parallel trials of the same 12 provenances. Increment cores were taken of a total of 1,267 sample trees, 19 years old. The location of the trial site generally affected the properties to a larger extent than the origin of the seed. The effect of the variation of wood density and fibre yield on the cultivation values of the provenances was only a few percentages on average, however, at most the effect was nearly 10%. Eastern Finnish provenances adapted well to western Finnish conditions.

The PDF includes an abstract in Finnish and French.

• Velling, E-mail: pv@mm.unknown
• Nepveu, E-mail: gn@mm.unknown

Berry yield of rowan tree (Sorbus aucuparia L.) was studied by picking and weighing the berries in a tree, counting the number of clusters by the eye, estimating the number of clusters by samples of 0.5 m², and by counting the dropped berries. In the last tree methods average weight of berries in a cluster was assessed by weighing a sample of clusters. The size of the tree and the abundance of the berries influenced the choice of method. The first two methods suited for small trees, the third for a tall tree with berries in abundance, and the fourth for those cases where birds had eaten a large portion of the berries.

The berry yields of 88 rowan trees were studied in Central Finland in 1983, a year of exceptionally high berry yield. The yield of berries averaged 23 kg per tree, the number of clusters 1,249 per tree and the number of berries 42,500 per tree.

The PDF includes a summary in English.

• Raatikainen, E-mail: mr@mm.unknown
• Rossi, E-mail: er@mm.unknown
• Vänninen, E-mail: iv@mm.unknown

This article reviews experiments and practical experience of forest management by the selection system in Finland. In an experiment of 25-year duration the annual growth of uneven-aged Norway spruce (Picea abies (L.) H. Karst.) stands was only about 50% of the average annual yield of even-aged stands in normal rotation on the same site.

In Finland the selection system is applicable under exceptional conditions only, viz. In intensively managed park stands and, on the other hand, on very marginal sites, e.g. on peat bogs and mountains near the tree-line. Even normal silviculture, however, may include cuttings which somewhat resemble selection system, e.g. removal of standards or restoration of mismanaged forests.

The PDF includes a summary in English.

• Mikola, E-mail: pm@mm.unknown

A survey was carried out among forest foremen and forest technicians to record their observations on the value of various swamp and forest types as producers of berries and on the effect of drainage of peatlands upon the berry yields. Comparative agreement existed on the best blueberry (Vaccinium myrtillus L.) forest types and on the best lingonberry (Vaccinium vitis-idaea L.) forest types of rather dry upland sites. Fuscum pine swamps or fuscum bogs were considered best for the most part as regards the yield of cloudberry (Rubus chamaemorus L.). The replies showed rather great dispersion.

Agreement existed as well on the relation between drainage of peatlands and the yields of our economically most important swamp berries, cloudberry and cranberry. 90% of those responding were of the opinion that drainage reduces the cloudberry yield in the long term and a full 97% indicated that cranberry crop diminishes as well.

The PDF includes a summary in English.

• Sepponen, E-mail: ps@mm.unknown

The yield of Gyromitra esculenta (Pers.) Fr. was surveyed during 1973–82 in a Norway spruce (Picea abies (L.) H. Karst.) dominated stand in Central Finland. The soil surface was treated with different light methods, mainly removing the vegetation and humus layer.

It was shown that is possible to improve the natural yield of G. esculenta by breaking the soil surface. In the 286 m² of treated the yield could be improved over 50 fold compared to the control area. In the untreated control area, the yield per hectare was 0.98 kg/yr. In treated plots the yield was 52.4 kg/yr (in the best year 191 kg/ha/yr). Fruit bodies of G. esculenta were found in treated plots every year after the soil treatment. The yield was at its best in the two first years declining later to the level of 10–20% of the first year’s yield.

The best natural yield was reached in the last year. The previous year’s precipitation was an important factor influencing the yield of the mushroom.

The PDF includes a summary in English.

• Jalkanen, E-mail: rj@mm.unknown
• Jalkanen, E-mail: ej@mm.unknown
• Jalkanen, E-mail: jj@mm.unknown
• Jalkanen, E-mail: mj@mm.unknown

Harvest index and number of associated traits were measured in a 16-year-old Scots pine (Pinus sylvestris L.) progeny test based on full-sib families. It was found that harvest index is a highly heritable trait and that a number of yield components are positively correlated with it. It is suggested that harvest index and tree ideotypes should be the basis of selection in cultivated trees. It is emphasized that an integrated approach to tree improvement including silviculture, soil science, industrial and economic constraints and tree breeding is a prerequisite for maximal response.

The PDF includes a summary in Finnish.

• Velling, E-mail: pv@mm.unknown
• Tigerstedt, E-mail: pt@mm.unknown

A study on the bilberry (Vaccinium myrtillus L.) was made in the municipality of Pihtipudas (about 63° 30’ N, 23° 30’ W) in 1977. Berry yield was surveyed by picking along 17 lines, each 1,000 m long. The lines were chosen randomly and were situated on different vegetation types throughout the municipality. The picking and use of bilberries were studied by an inquiry addressed to a random sample of families living in the area. Marketing of bilberry was investigated by means of report based on purchasing certificates.

The total yield of bilberry in Pihtipudas was 2.4 million kg (21.9 kg/ha). The yield per hectare were best on Vaccinium and Myrtillus type sites, and on swampy heath sites, where the yield was about 27–65 kg/ha, 50% of the yield on the Vaccinium type and 25% of that of Myrtillus type. Only 1.8% of the total bilberry yield was picked from old forests. Women contributed 54, men 34 and children 12% of the volume.

72% of the berries were used for home consumption by the families, 24% were sold and 4% were used for other purposes. The earnings from bilberries for the families that sold berries was in average FIM 178.

The PDF includes a summary in English.

• Raatikainen, E-mail: mr@mm.unknown
• Raatikainen, E-mail: tr@mm.unknown

In dealing with the effectiveness of forest taxation reform as a means of economic policy, the paper starts by recalling certain objectives of taxation, as well as the effect on aggregate demand of taxation in general. The effect of forest taxation depends on such factors as (1) whether the woodland owner has a regular income from a source other than forestry; (2) the system of taxation (whether taxation of actual stumpage revenue or of area-based yield); (3) the progression of taxation; and (4) the woodland owner’s income level.

The problem is illustrated by an example taken from Finland, where forestry revenue is taxed on the basis of area-based yield. A shift to taxation of actual stumpage revenue, as is proposed, is assumed. The effectiveness of this change is studied in terms of how far the assumed change is consistent with the objectives of the national economy. It is assumed that a shift to taxation of actual stumpage revenue would cause a decline in roundwood supply. A sensitivity analysis is then applied to detect the effect on tax revenue and national income of the tax reform. It is likely that a 10% decrease in fellings would bring about a reduction of tax revenue which would not be compensated for by the more perfect exposure of forestry income to taxation brought by the reform. The effect on investment, production, employment, differences in individual and regional income, and on the international balance of payments also disfavour the suggested change.

• Riihinen, E-mail: pr@mm.unknown

Establishment of seed orchards to produce genetically improved seed started in the USSR in the 1960’s. The aim is that within 10–15 years the total seed production will reach 50% of the seed used. The paper describes seed production in seed orchards of Scots pine (Pinus sylvestris L.) in the forest-steppe of the European part of the USSR. The orchards have been established either by grafting or by planting of seedlings originating from plus trees. The grafts begin flowering relatively early, however, only at the age of 8–10 years seed crops become relatively regular and abundant. The cone yield in young seed orchards have great variability, and the yield of cones varies between clones. Cone yield does not always correlate with a good seed yield. One of the reasons for high amount of empty seeds is the difference in the periods of flowering between the clones.

The seed crops can be improved by establishing optimal conditions for the growth of the trees. Also, when a seed orchard is founded, the peculiarities of the generative activities of the clones and their reactions to changes in the environmental conditions must be taken account by taking an individual and selective measure approach to improvement measures. The orchards can be established with clones for their genetic combining ability and their requirements for the stimulation of seed-bearing.

The PDF includes a summary in Finnish.

• Efimov, E-mail: je@mm.unknown

Curly birch (Betula pendula f. carelica Sok.) is characterized by large variations in stem form and the internal structure of the wood, and is generally divided in to four types on the basis of visible external stem characteristics. First plantation experiments in Finland in the 1920’s in experimental areas of the Finnish Forest Institute, had become ripe for cutting and were felled. The study material of this study consists of one 52-year old and three 42–43 -year old stands of curly birch.

The yield suitable for plywood manufacture from the oldest stand was 34,777 kg/ha and that of curly grained branch wood 39,452 kg/ha. The corresponding figures of the other stands were, on average 24,219 and 57,271 kg/ha. The yield from the stands were sold at the present-day price. The result was economically better than from any other forest tree species grown in Finland. The younger stands were obviously cut too early. It was concluded that the genetic quality of the seedlings used in the plantations in the 1920’s and 1930’s was not very high.

The PDF includes a summary in English.

• Raulo, E-mail: jr@mm.unknown
• Sirén, E-mail: gs@mm.unknown

A study on the lingonberry (Vaccinium vitis-idaea L.) was made in 1976. The berry yield was studied by picking along 17 lines, each 1,000 m long. The picking and use of lingonberry were studied by an inquiry addressed to the families engaged in such an occupation. The marketing of the lingonberry was investigated by interviewing purchasers, and by means of reports based on purchasing certificates of the purchacers. The total yield of lingonberry in Pihtipudas was 1.2 million kg or 18 kg per hectare of productive forest. Only 7% of the total yield of the berry was picked. 47% of the lingonberries picked were used by the families themselves, 48% were sold and 5% were used for other purposes. The families who sold lingonberries earned, on an average, 350 Fmk.

The PDF includes a summary in Finnish.

• Raatikainen, E-mail: mr@mm.unknown

The effect of spacing on the first-year yield and height increment of Alnus incana (L.) Moench, Populus tremula L. x Populus tremuloides Michx. (Populus x wettsteinii), Salix ’Aquatica Gigantea’, and Salix phylicifolia L. was studied at the Arctic Circle Agricultural Experimental Station in Northern Finland. S. ’Aquatica Gigantea’ gave yields which were twice as high as those of the other species in the study. The highest yields were of the order of 60 tons per hectare (fresh yield including foliage). The annual height growth in S. ’Aquatica Gigantea’ was about 100 cm, in the others about 30–50 cm. S. ’Aquatica Gigantea’ had a maximal height growth when the distance between the seedlings was 25 cm.

The PDF includes a summary in English.

• Pohjonen, E-mail: vp@mm.unknown

The technical term reduced yield stands – sometimes reduced yield soils – is widely used in the Finnish forest literature. However, there is no clear definition of the notion reduced yield and no explanation of how this notion is measured in the classifications. Some committee reports and bill proposals and some laws and statutes use the reduced yield forest soil. No definition can be found. In my opinion the term reduced yield forest soils ought to be completely abolished until forest soil experts can perhaps define what it means, if they consider such a concept useful.

Explanations for the term reduced yield stands can be found in the descriptions of classification systems of stands. According to them, the criterion is partly silvicultural (site, species of tree), partly mensurational (volume, sometimes growth), partly economic. No explanation is found as to how the economic aspect is measured, nor about the limit of a full yield and reduced yield.

In my opinion such a term is confusing. I therefore suggest that the term reduced yield stand ought to be abolished. If something is needed instead, I suggest the term understocked stand, defined as a growing stock under certain percentage of a fully stocked stand. The notion of economic reduced yield cannot be generally tied to certain silvicultural and mensurational characteristics of stands. The economic aspect of certain kinds of stands may differ, depending on the owner of the forest and his economic situation, the location of the forest, the composition of the whole forest ownership unit, etc.

The PDF includes a summary in English.

• Saari, E-mail: es@mm.unknown

The present paper presents studies on the influence of some relatively common defects of Scots pine logs in Northern Finland on both the sawing yield and on the quality of the sawn goods. The study was based on test sawing of 25 logs for each of the defects (upright limb, heart shake and various kinds of wounds and scars) at Karihaara sawmill. The yield was graded into grades used for export timber according to the system of the sawmill. The proportion of the different export grades (U/S), fifths, sixths and culls) were used as characteristics together with the ratio of raw-wood consumption expressed as cu.ft/std.

Upright limbs occurring in a piece of sawn timber was shown to lower its quality to fifth grade in 43.5%, to sixth grade in 46.8% and to the category of culls in 6.5% of all cases. Only 3.2% of the cases the piece remained in U/S-grades. The size of the upright limb was the most important factor lowering the quality and affecting the ratio of raw-wood consumption.

Heart shakes are relatively common defects in pine logs deriving from over-mature trees. The quality-decreasing influence on the sawing yield depends clearly on the length of the shake in the cross-section. The same characteristics also decreases the ratio of raw-wood consumption. In addition, twisting and star shakes are considerably more harmful than straight ones. If rot occurs in connection with shakes, the places marred by the shakes are only capable of yielding sixth-grade sawn goods or culls.

Scar encountered in logs affect the sawn yield and its quality to quite a varying degree, but these defects themselves may also vary considerably both in size and quality. The length of the scar is highly significant as a quality-decreasing factor. If, in addition, rot is encountered, the defect is of a severe nature.

The PDF includes a summary in English.

• Heiskanen, E-mail: vh@mm.unknown

Silva Fennica Issue 92 includes presentations held in 1956 in the 8th professional development courses, arranged for forest officers working in the Forest Service. The presentations focus on practical issues in forest management and administration, especially in regional level. The education was arranged by Forest Service.

This presentation concerns the evaluation of forest land to be surrendered for a settlement farm. According to the Settlement Act, state land surrendered for settlement purposes should fetch the price that any sensible buyer would pay in buying the land. The prices used in evaluation are, however, still the prices of 1944. A new method for calculating the yield in terms of value of forest land has been developed by professor Yrjö Ilvessalo, based on the König-Faustman formula. This method is described in Tapio Forestry Manual.

• Linnamies, E-mail: ol@mm.unknown

The study is continuation of the earlier structure and growth studies of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) in Forest Research Institute. The material represents birch stands (Betula verrucosa, now B. pendula, and B. Pubescens L.) in Southern Finland. The stands were treated with different fellings, and in regard to their silvicultural condition classified as good, satisfactory and unsatisfactory. Height of the trees, height of living crown, volume, increment and volume increment and development of stem diameter series was measured.

The most characteristic difference between the silviculturally good and poor stands was that the the annual increment of the good stands concentrated into large size trees, and the increment of unsatisfactory stands into small and inferior trees.

It is concluded that if the aim of stand treatment is to produce large and high quality volume increment, the most favourable stand volume of  birch stands, compared with naturally normal stand volume, seems to be 90-85% at the age of 41-55 years, and 80-70% at the age of 56-65 years. If growth of large size trees is aimed at, the maximum number of the dominant trees per hectares cannot be more than 400 at the age of 50-60 years.

The article includes a summary in English.

• Kuusela, E-mail: kk@mm.unknown

A committee was appointed in 1940 to prepare a proposal for reform of forest taxation. The taxation based on net income of forestry was considered to have limitations, and the actual net income had been observed to be markedly higher than the income that was used in taxation.

The report describes in detail the principles and shortcomings of taxation used since 1922. These include inaccuracies in the forest areas of a woodland estate, and weaknesses in classification of forest land and demand zones. The committee suggests several improvements in calculating the taxable income, which in the new calculations is based on yield on terms of value.

The article includes an abstract in German.

• Metsäverotuksen uudistamiskomitea, E-mail: –

The Moscow Peace Treaty created a need to calculate values of large forest areas in Finland, such as the value of the private and state forests lost in the Second World War, or value of the remaining forests and the value of forests to be assigned to the evacuees. The article describes principles of evaluation of large forest areas. It concludes that use of felling value of the trees is the right method only if felling of the whole tree stand and sale of the wood is actually possible. If these prequisites cannot be fulfilled, the right method to evaluate the forest area is yield in terms of value. When calculating the yield in terms of value, also other incomes and costs related to fellings should be included.

The article includes an abstract in German.

• Saari, E-mail: es@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 different methods of assessing tree growth.

• Ilvessalo, E-mail: yi@mm.unknown

The article is a review on methods used in Central Europe and in Finland to construct growth and yield tables, and on their defects and advantages. One of the main defects of growth and yield tables prepared previously in Central Europe is that the site quality classes for different tree species have been formed independently and using different principles. Thus, the yields of different tree species on a similar site can’t be compared. In addition, the quality classes of this kind of growth and yield tables and growth series are artificial.

The Society of Forestry in Finland (now Finnish Society of Forest Sciences) started to prepare new yield tables for the most important tree species in Finland in 1916. The new yield tables aimed to improve the yield tables made in Central Europe in two aspects. Firstly, the quality of the site of each sample plot was assessed on the spot and independently from the standing crop. Thus the sample plots of each site class in setting up the growth series can be treated as independent groups. Consequently, the quality classes are be the same for all tree species. Secondly, mathematical-statistical methods were used to determine which of the stands that belong to the same quality class belong also to the same growth series.

The PDF includes a summary in Finnish.

• Ilvessalo, E-mail: yi@mm.unknown

One of the difficulties in constructing growth and yield tables has been to determine which of the sample plots growing the same tree species and belonging to the same forest site type, with reference to the quality of stands, have to be included in the same growth series.

New growth and yield tables for the most important tree species were constructed in Finland in 1916–1919, using new principles that aim at avoiding some of the common weaknesses. There were two main differences to the earlier work. First, the site quality class (forest site type) was determined for each sample plot when the sample plot was measured, independently of the stand occupying the site. In this way it was possible to treat the sample plots of each site as an independent group from the beginning, and so that the quality classes were the same for all the tree species. Second, mathematic-statistical methods were used to deduct the so-called stem frequency distribution series, when studying which of the sample plots of the same quality class belong to the same growth series. They represent the average number of stems of the different diameter classes. A more detailed description of the method used to create the growth and yield tables is published in Acta Forestalia Fennica no. 15.

In the PDF is included a summary in Finnish.

• Ilvessalo, E-mail: yi@mm.unknown

The present study proposes to calculate the economic sequence of two of Finland’s three main tree species, Norway spruce (Picea abies (L.) H. Karst.) and silver birch (Betula pendula Roth) when planted on Oxalias-Myrtillus type sites where both species are equally suitable, on biological grounds. In addition, the accuracy and applicability of the present Finnish yield tables to an economic comparison is tested. Benefit/cost ratio was selected as criterion of profitableness. All future net incomes and costs were discounted into the planting time and added together. The ratio between the discounted net revenues and the discounted investment costs (later called profit ratio) was the criterion. There is no reliable method to forecast the future wood prices, therefore two price ratios, birch veneer timber to spruce pulpwood and birch cordwood to spruce pulpwood, were chosen as free variables. The economic sequence of the tree species was determined as the function of these variables.

The main conclusions are, first, that under the present price ratios spruce appears to be the better choice for the forest owner, and the most promising policy for changing the situation seems to decrease the production costs of plants in birch nurseries. Second, the present Finnish yield tables are not consistent or accurate enough to enable any sufficiently reliable economic comparisons of tree species in artificial regeneration. The possible error of difference between two rather uncertain estimates is big. More work is needed to construct a uniform system of yield tables covering all main tree species, all site types, all macro climate conditions and all types of regeneration.

The PDF includes a summary in English.

• Keltikangas, E-mail: mk@mm.unknown
• Tiililä, E-mail: pt@mm.unknown

Examination of stands developed under natural conditions can be used to provide basis for comparison for study of the development and yield of stands treated with intermediate fellings. In Finland, the first investigation and the yield and the structure of natural normal stands were published in 1920. This investigation on development and yield of the natural forests of Kainuu in southeastern Northern Finland is based on 92 sample plots on three forest types; Empetrum-Vaccinium type (EVT), Empetrum-Calluna type (ECT) and Vaccinium-Myrtillus type (VMT).

The Scots pine (Pinus sylvestris L.) sample plots represented variation of age classes for construction of mean development series. The Norway spruce (Picea abies (L.) H. Karst.) of the region are so old that development series could be obtained only for dominant trees based on stem analysis.

The average development of Scots pine stand on EMT type within the region is on average more rapid and the yield in cubic volume quantitatively larger and structurally better than that on ECT type. Self-thinning during the early decades of EVT is slower. The pine stands are denser in the age of 70 in Kainuu compared to Central Northern Finland, but the development and yield are similar.

The development, yield and structure of natural Norway spruce stand on VMT proved considerably inferior to the average level of pine stands on EVT, and to a major part on ECT. The mixed pines on spruce sample plots have developed better than spruces of equal age. Spruce stands on VMT in the area developed markedly better than Geranium-Dryopteris-Myrtillus (GDMT) in Central Northern Finland.

It seems that a spruce stand seems to require more fertile site type in north than in the southern part of Finland. These fertile types are relative rare in the north. In the region, the best results are received with pine. As a rule, also the yield of birch (Betula sp.) is poor in the region.

The PDF includes a summary in English.

• Ilvessalo, E-mail: yi@mm.unknown

The objective of this paper was to study the influence of defects of Betula pendula Roth and Betula pubescens Ehrh. on the quality, value and quantity of veneer cut produced by rotary cutting, to prepare grading rules for veneer birch and to determine the minimum quality for veneer birch, and to assess the quality and quantity of veneer yield in rotary cutting of bolts of different grades. Data for the study was collected in 1953-1963 from six plywood factories in Finland.

The effect of knot marks, knot bumps, dry and rotten knots, sound knots, sweep and crookedness, upright limbs, heart rot, open and overgrown scars and bark peeling defects in the bolt on the quality and yield of veneer is described. Recommendations for grading rules were defined on the basis of the result. The rules include three grades, for which certain defects are allowed. In the first grade are accepted bolts, which of the veneer yield included at least 30% of veneer of grades A and B when all jointing and end-clipped sheets were taken into account. In the second grade were accepted bolts, which of the main part of the veneer yield still is surface veneer on the basis of the wood quality. Of the third-grade bolts at least one third of the veneer yield ought to be surface veneer.

The PDF includes a summary in English.

• Heiskanen, E-mail: vh@mm.unknown

The objective of the present investigation was to clarify the influence of raw material on the quantity, and especially quality of rotary cut birch veneer by running cutting tests with constant tool setting under factory conditions and with bolts of normal size. The quality of the veneer was mainly examined in laboratory.

The result showed that with an increase in bolt size the yield increases and reaches the maximal value in the diameter range of 251–275 mm and 226–250 mm for 60-inch and 50-inch bolt, respectively. With a decrease in bolt length the yield becomes higher. With the increase in the bolt size the quality of the veneer improves.

Defects in the shape of the bolt, such as crookedness, taper and oval form, decrease the yield. The good quality of the bolts affects most the yield of full-size sheets. Increase of knottiness decreases the yield by 4–5%. Lowering of the bolt temperature below 0 °C causes a sharp decline in the yield. Moisture content of the wood did not markedly affect the yield, but it improved the quality of the veneer. The minimum moisture content was 75%.

For the technical quality of the veneer, bolt temperature was the most decisive raw material factor. Also shape defects, of which crookedness was most serious, decreased the technical quality. Increase in summerwood percentage improved the quality.

The PDF includes a summary in English.

• Meriluoto, E-mail: jm@mm.unknown

The objective of this study has been to discover some of the basic principles on which an increment for a large forest area might be forecast. Because the stands in a large forest area vary considerably in density and are subject to different kinds of treatment, the main interest falls on the stand characteristics which determine the increment percentage in such forest conditions as these. The material used in the study has been published earlier, it consisted of sample plots of Scots pine (Pinus sylvestris L.) stands (Nyyssönen 1954).

Increment functions are of great importance in the increment forecast for cutting budget. Because 60-80% of the variation in the increment percentage can be explained by stand characteristics in circumstances where the age of the stand is 40-130 years and the volume vary with a coefficient of variation 0.6-0.7, regression equations for increment percentage may be based on a number of sample plots smaller than in a growing stock inventory in the same conditions. It is possible to get accurate results with relatively small number of sample plots. Furthermore, the smaller amount of increment sample plots makes it possible to develop measurement techniques.

The increment functions enable study of increment as a biological process. However, conclusions about biological process on the basis of regression equations should be made with caution. Still, regression analysis is a powerful tool in yield studies.

The PDF includes a summary in Finnish.

• Kuusela, E-mail: kk@mm.unknown
• Kilkki, E-mail: pk@mm.unknown

The Finnish forest industry is undergoing a vast expansion, which has raised questions of forest balance. This paper studies the possibilities to increase the amount available timber by means of forest drainage. About third of the Finnish land area is peatlands. The calculations of the investigation are based on Forestry Board districts. Based on earlier studies, there is estimated to be 3,042,000 ha of true drainable swamps, 973,000 ha of poor swamps, 1,381,000 ha of uplands in need of drainage, and 1,205,000 ha of drained peatlands. Therefore, the area of drainable and drained lands totals 6,6 million ha, and requirement of forest drainage 5,4 million ha. The drainage hardly reaches this extent, however. It can be assumed that part of the poor swamps is uneconomical to drain. In addition, a half of the paludified forest land will probably not be drained. Thus, it can be estimated that the area to be drained in the future is about 5 million ha. It seems possible that this area could be drained within about 50 years with the present draining capacity.

Draining of all objects of forests would increase the annual increment of our forests, in time, by about 10.5 million m³. This would signify an increase of 23% compared to the present growth of the forests. The increase in the growth consists mainly of softwood: 16% is birch, and the remaining 84% almost equally of Scots pine and Norway spruce. The increase of growth is relatively slow. Depending on the rate of the drainage program, the mean increase of growth will be reached in about 25–35 years. The increase in removal indicated by the increase in the mean increment will be reached in only 50–60 years.

The PDF includes a summary in English.

• Heikurainen, E-mail: lh@mm.unknown

In Southern Finland Scots pine (Pinus sylvestris L.) is mainly sown on Vaccinium and Myrtillus-type sites. The material for the study was collected by measuring sample plots in pure, even-aged pine stand that had been sown. The sample stands had been thinned from below.

The volume of the stands was roughly the same as that of repeatedly thinned pine stands. The cubic volume of sown pine stands is 65–90%, varying according to age, of that of natural-normal pine stands. The current annual volume increment of stands on Myrtillus-type was 8–9 m³/ha at age of 20–30 years. The peak was reached at age of 35 years with 9 m³/ha, in the following years the increment is about 8 m³/ha until the age of 60 years. On Vaccinium type sites increment reaches 6–7 m³ level at age of 30 years, and attains the peak of 7 m³/ha at the age of 45 years. Annual increment was in young and middle-aged Myrtillus-type stands about 10% greater, and on Vaccinium-type stands 15–20% greater than in natural-normal pine stands.

The total volume increment in 70 years old Myrtillus-type stands was 580 m³/ha over bark, and in 80 years old Vaccinium-type stands 520 m³/ha. The total removal on Myrtillus-type sites totalled nearly 350 m³/ha in sown pine stands up to 70 years of age, and 280 m³/ha on Vaccinium-type stands. The total yield in sawn timber per hectare rises up to 6,300 cubic ft in a 70 years old stand on Myrtillus-type stands, and 5,300 cubic ft in Vaccinium-type stands. In conclusion, the volume and increment development of managed pine stands established by sowing up to 70–80 years of age is largely the same as in repeatedly thinned pine stands, but the structure and yield offer greater advantages. The investigation demonstrates that, in the case of Scots pine, sowing is an advantageous method of regeneration. Sowing is an advantage especially in the cases where natural regeneration is uncertain and slow.

The PDF includes a summary in English.

• Kallio, E-mail: kk@mm.unknown

An estimate of value of a forest holding is needed, for instance, when the holding is sold. There is, however, no standard method for forest valuation. This paper describes a method based on yield in terms of value that is estimated on the basis of cutting budget. The first, mensurational part of the investigation concentrates on calculation of cutting budget that can be used in forest valuation. Second part studies how chronological order of fellings changes allowable cut in forests that differ by age-class distribution and other structural properties. Structure and variation in the structure of silviculturally different forests are determined for the forests that form the data for the investigation.

According to the study, even if the forests studied in the investigation included forests which structure differed in their age-class distribution from normal forests, they could be managed in a such way that in 5-6 decades the age-class distribution resemble that of a normal forest, and have growing stock that correspond the stock of forests in Southern Finland, about 80-110 m3/ha. Based on this, the cutting budgets of the later decades of the first rotation can be assumed to be nearly even. The original age-class distribution of the forest affects, however, allowable cut of the forests during the first decade. The revenues of the first decade have small impact on the value, the later decades strong. Consequently, development of the most valuable part of the allowable cut, timber trees, has big impact on the value. The results show that in young forests the planned cut including the proportion of timber trees increases, in middle-aged forest it is relatively even, and in old forest declining. The results indicate the order of magnitude the planned cut can be in near future in diferent kinds of forests, and when different felling regimes are used to reach different goals.

The PDF includes a summary in German.

• Kallio, E-mail: kk@mm.unknown

Permanent sample plots are considered to be the most reliable basis for investigations into structure and development of stands. Such sample plots, established since 1924 in Finland, have been used to study thinnings of varying intensity. These studies are yet too short to give comprehensive conclusions. It is also possible to base the studies on sample plots measured in managed forests and gain in this way information suitable for practical purposes. In this investigation development of stands treated by two different methods, repeated thinnings and repeated selection cutting were studied in pure, even-aged Scots pine (Pinus sylvestris L.) stands in Southern Finland, on three forest types.

The results show that volume increment level of naturally normal stands seem to have been reached easily by stands treated with repeated thinnings. With advancing age, the growing stock of thinned stands fall short from the natural stands. As thinnings have removed primarily the poorest trees, the increment is distributed over trees of a larger size more in thinned than in naturally normal stands.

When intensive cuttings have resulted in a relatively small growing stock, the decrease in volume increment leads to considerable decrease in volume. The size of the tree has no essential effect – within certain limits - on the volume increment of the stand, if the volume removed is similar. However, every intermediate thinning removing largest-sized trees may result in the prolonged rotation. Since the volume increment of an older stand is much smaller than earlier, intermediate thinnings removing largest-sized trees should be avoided if the aim is the greatest volume yield. The growing stock of middle-aged or older stands untreated or treated with slight cuttings only can as a rule be considerably reduced without volume increment declining.

The PDF includes a summary in English.

• Nyyssönen, E-mail: an@mm.unknown

The article discusses use of felling value in determining the value of growing stock. It has been argued that use of felling value to calculate value for a forest holding usually leads to too high values. Consequently, when setting a price for growing stock, felling value should be applied only for such parts of the property that can be sold immediately at a current price.

The article describes in detail assessment of the felling value, first using timber assortments of the stand, and second, by conducting the felling value using parameters affecting the value, such as volume and tree species of the stand. An assessment method  was developed to calculate the value by using structure of a cubic metre of timber in a stand. The structure was determined using data of the national forest inventory in Finland. Finally, the article discusses application of the method.

The PDF includes a summary in German.

• Lihtonen, E-mail: vl@mm.unknown

Natural regeneration has been studied so far mostly on the perspective of regeneration, while the production capacity of the seed crop stand has been of little interest in the earlier studies. This paper studied volume growth of the seed trees and the economic impact of this regeneration method both in a literature review and measuring sample stands consisting of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) dominated stands and mixed forests in Norway.

It is concluded that in the most cases the seed tree stands give better pulpwood and timber yield than the stands in the average. The reason might be that the elite stems can better use their production capacity, and, thus, reach bigger and more valuable dimensions. Even though the growing stock diminishes in the seeding felling, the growth of the stand does not decrease or decreases only little. At the same time, the quality growth improves. In addition, the new tree regeneration is achieved usually without extra costs, and there is no unproductive time period in the stand.

• Barth, E-mail: ab@mm.unknown

To achieve a continuous and constant timber flow over a longer time period, the forest holding structure should be close to normal forest or regulated forest. Concept of normal forest is presented as the model of achieving the highest possible sustainable yield and hence also the best economic return. The article discusses the regulations on the management of a forest holding with the view on regulating the forest yield.   

Felling need to be planned according to the forest site and tree species. The main tree species for silvicultural purposes are pine, spruce and birch. After the widely used controlled burning of forests the state of Finnish forests is mostly weak and far from the “normal forest”. Majority of forests are of young and there are lots of broadleaved forests.  Because of the great variation of the forest sites and their productivity as well as the small size of holdings in Finland, the selection of forest management regime, mainly the felling style (clear cut or light selection) is also important. The idea of management plans is represented.  

• Lönnroth, E-mail: el@mm.unknown

The article contains tree lectures given in the meeting of the Geographical Society in Finland on February 25^th 1921.  The titles of the lectures are I Forest types in general, II Forest types as a basis for new growth and yield tables in Finland, and III Other research on forest types.  

The first lecture is a follow-up of the Cajander’s 1909 published article on forest types. It deepens the theory on forest types. The classification into forest types represents primarily different plant communities of ground cover. The types are named after the characteristic plant species, indicator plants, however, many other species appear in different abundance.

The second lecture represents the research proceedings of mensuration of forest stands of different types to compile yield tables for pine.  The forest types differ from each other distinctly on their growing preconditions, but inside one class the variation of the growing conditions is so small, that the classification can be used for yield tables, determining the basis of taxation and for classification of forest based on height over age.

The third lecture is a summary of other studies about forest type classification.  They confirm the results presented in earlier lectures. 

• Cajander, E-mail: ac@mm.unknown
• Ilvessalo, E-mail: yi@mm.unknown

New growth and yield tables were prepared for Southern Finland. To finalize the tables, it had to be determined whether the forest site types developed by Cajanus could be used in mensurational research.

Comparative study was performed in 1916-1919 to study the growth of the trees in different forest site types. Total of 467 sample sites were measured in Southern and Central Finland. All the forest site types were found to have a distinctive vegetation typical to the site. It can be concluded that the ground vegetation can be used to determine the forest site type. The growth of trees was different in different forest site types, yet similar within each site type. The forest site types are uniform, natural and easy to determine, and can thus be used to classify the forest stands and used in mensurational research and a basis to growth and yield tables.

The PDF includes a summary in German.

• Ilvessalo, E-mail: yi@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.

• Lassila, E-mail: il@mm.unknown

The aim of the study is to generate yield tables that enables calculating the stumpage values of the forests in different ages. The article investigates the diameter distribution of a stand at the breast height and their changes with the age of the stand.  In an even-aged stand the calculating of the stumpage value is based on height and breast height diameter. Hence the diameter distribution of a stand determines the stand volume, the stem frequency distribution series can be used as the basis of compiling the yield tables, in which the volume is the main factor.   

The study is based on spruce and pine mensuration data from Finland, pine stands from Prussia, and spruce stands from mountainous area of Switzerland. The article presents the characteristics of stem frequency distribution series based on the data. The studied characteristics are arithmetic middle, dispersion, asymmetry (skewness) and excess.

It can be recommended to create tables that show the different developments for age classes. Based on such tables the expected value of the stand can be calculated in practical forest management. Determining a general value of a stand in different forest site types would be important for forest valuation and forest statistics.    

• Cajanus, E-mail: wc@mm.unknown

The study is based on research in Germany, Austria, Switzerland, north Russia and Siberia, and Finland in years 1906-1908. The objective of the study is to find means to create forest site classes or forest types to direct practical forest management.

The article presents the classification of forests into site classes (Oxalis-Majanthemum type, Myrtillus type, Vaccinium type and Calluna type). The second part of the article represents different methods to calculate growth and yield tables for different forest site types. The conclusion of the study is that forest areas with similar vegetation and forest type can be handled in one way for forest management. 

• Cajander, E-mail: ac@mm.unknown

The aim of this paper was to study the nature of the relative areal differences in the Finnish forests in respect of timber yield, intensity of exploitation and stumpage prices. The yield index is the most inconsistent and the source of the greatest regional differences. The differences arise even in Southern Finland, as the yield in the South-West is only 80 % of that obtained in Eastern Häme. The areal variations in the wastage index are of the order of only 10 % at most, and the stumpage price index is relatively constant, remaining within the 10 % limit, as far north as the southern boundary of the province of Oulu.

Indices for the forest yield and final forest returns suggest that the further one goes in Finland the greater the discrepancy between the two, as a consequence of the increase in stumpage price differences. Thus, whereas the yield per hectare in North-Eastern Finland is about 20 % of that in Eastern Häme, the stumpage price is similarly only just over 50 % of that prevailing in the latter area. This, the resulting returns per hectare are only 10 % of those obtainable in the more southerly area. When the return per hectare for the Forestry Board District of Eastern Häme is represented by the index 100, one then obtains corresponding return indices of 21.0 for the Northern Ostrobothnia and Kainuu area, 13.0 for Lapland and 10.0 for North-Eastern Finland. Thus, it may be said that roughly 10 hectares of forest land in Lapland, 5 in Northern Ostrobothnia or Kainuu, or 2 in Northern Karelia or the coastal area of southern and central Ostrobothnia would be required to produce the same returns as 1 hectare in Eastern Häme. This represents an extremely wide range of variation within the borders of one country.

This work provides a clear and sufficiently accurate impression of the order of magnitude of the areal differences in returns from the Finnish forests, and may thus serve as an adequate basis for the taking of decisions in this field.

The PDF includes a summary in English.

• Alho, E-mail: pa@mm.unknown

The aim of the present study was to describe the forest types of Finnish mineral forest lands as a uniform whole in the light of stand development and wood production.

The study shows that it has been possible to work out uniform age-based development series for different stand characteristics for forest types on mineral forest lands in Finland. There is generally a clear difference in the development series of various stand characteristics and their average values between different forest types. The exceptions in a few places have been explained as depending on certain factors. The differences between adjacent forest types in order of their quality are of varying magnitude, thus differing from a schematic site quality classification obtained through calculation. Consequently, each forest type has its own development series with regard to the stand characteristics.

The number of forest types in the whole country is rather high. However, the different forest types are limited to different parts cf the country in such a way that there is no need for more than 5–6 forest types and 4 northerly sub-forms (-types) in each region, except in the border areas between the regions. In Finland the forest types have been the basis of forest site classification in forest research and practical forestry over a period of half a century. In pointing out the necessity of further study of forest types, Cajander has stressed the examination of differences in the compositions of vegetation between different classes of density of tree-stand and building up average descriptions of vegetation in such classes in young, middle-age and old stands. The same may be caused by some other factors which also are of essential influence to the composition of the vegetation.

The PDF includes a summary in English.

• Ilvessalo, E-mail: yi@mm.unknown
• Ilvessalo, E-mail: mi@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.

• Vuokila, E-mail: yv@mm.unknown

The aim of the study was to find out the ratio of raw wood consumption and the quantity and quality of the sawing yield using circular saws. The unit of study was one single log, the Norway spruce logs were divided into two grades and Scots pine logs in three grades. The principal material of the study was collected in 1950-51 using four types of saws of type EKA-50. The data consisted of 1,690 logs.

On the basis of the material, the efficiency of centre-piece sawing was 63.9% of the technical volume. On the average, 32.1% was unsorted goods, 11.5% fifths, 19.1% sixths and 1.2% culls. For spruce, the efficiency was superior to pine, which means that the consumption of raw wood for preparation of one standard of sawn goods is smaller in spruce than in pine. The volume of side boards trimmed reached about 2% of the total log volume. The efficiency of sawing and the ratio of raw-wood consumption were calculated both on the basis of the estimated and actual volume of trimmed goods. The raw-wood consumption is particularly good in logs of small and large top-diameter.

Goods sawn with circular saw have a characteristic shape. They are thinner at the ends than in the middle parts, and the deviation from the correct measure is larger in the first than in the last end of the pieces. They are also wedge-shaped because of the first piece sawn is thinner than the second one. The deviation from the correct measure exceeded the allowance for shrinking in seasoning. The goods are often under sized even if surplus measure occurs. In goods sawn using frame saws, however, it was difficult to discover any deviation from the correct measure.

The PDF includes a summary in English.

• Granvik, E-mail: bg@mm.unknown

Plant growth-promoting rhizobacteria (PGPR) and filtered sludge are widely used to improve soil fertility and plant yields. In this study, we evaluated the impact of sludge and/or PGPR application on the nutrient contents and enzyme activities of the soil as well as on plant growth. We planted bare-root eucalyptus seedlings in (1) soil amended with filtered sludge from Nanning sugar factory (FS), (2) soil amended with filtered sludge + PGPR (BF), and (3) non-amended soil (control). Soil fertility and eucalyptus growth were determined after 3, 6, 9, and 12 months. Results demonstrated that FS treatment significantly increased eucalyptus growth compared to the control, particularly after six months. Bacterial fertilizer (BF) also increased soil urease and sucrase activities, although differences diminished over the study period. Our findings suggest that the integration of bacterial fertilizers and filtered sludge can serve as an effective and environmentally friendly strategy to improve soil health and promote sustainable eucalyptus cultivation. This research contributes to the growing body of evidence supporting the use of bio-fertilizers in forestry practices, highlighting their potential to reduce or replace the use of chemical fertilizers while increasing plant productivity.

• Ren, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China; Forestry College, Guangxi University, Daxue E Rd, Xixiangtang District, Nanning, Guangxi, 530004 China https://orcid.org/0000-0002-0156-0726 E-mail: renhan1225@163.com
• Chen, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China E-mail: 21211270104@stu.wzu.edu.cn
• Qin, Forestry College, Guangxi University, Daxue E Rd, Xixiangtang District, Nanning, Guangxi, 530004 China E-mail: qinxiaohong186@163.com
• Zhang, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China E-mail: 00811091@wzu.edu.cn
• Lv, Forestry College, Guangxi University, Daxue E Rd, Xixiangtang District, Nanning, Guangxi, 530004 China E-mail: lvchengqun8@163.com
• Zhou, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China E-mail: rosechl@wzu.edu.cn
• Chen, College of Life and Environmental Sciences, Wenzhou University, Wenzhou, Zhejiang, 325035 China https://orcid.org/0000-0002-3043-6919 E-mail: hualin2100@wzu.edu.cn

The purpose of this study was to prepare a comprehensive, computerized teak (Tectona grandis L.f) plantation yield model system that can be used to describe the forest dynamics, predict growth and yield and support forest planning and decision-making. Extensive individual tree and permanent sample plot data were used to develop tree-level volume models, taper curve models and stand-level yield models for teak plantations in Panama. Tree volume models were satisfactorily validated against independent measurement data and other published models. Tree height as input parameter improved the stem volume model marginally. Stand level yield models produced comparable harvest volumes with models published in the literature. Stand level volume product outputs were found like actual harvests with an exception that the models marginally underestimate the share of logs in very large diameter classes. The kind of comprehensive model developed in this study and implemented in an easy to use software package provides a very powerful decision support tool. Optimal forest management regimes can be found by simulating different planting densities, thinning regimes and final harvest ages. Forest practitioners can apply growth and yield models in the appropriate stand level inventory data and perform long term harvest scheduling at property level or even at an entire timberland portfolio level. Harvest schedules can be optimized using the applicable financial parameters (silviculture costs, harvesting costs, wood prices and discount rates) and constraints (market size and operational capacity).

• Seppänen, Verdas Oy, Kihlinkuja 7, FI-50600 Mikkeli, Finland E-mail: petteri@verdas.fi
• Mäkinen,  Simosol Oy. Hämeenkatu 10, FI-11100 Riihimäki, Finland E-mail: antti.makinen@simosol.fi

The objective of the study was to ascertain the effects of tree selection (thinning from below, from above and according to stem quality) and timing of first commercial thinning (early and delayed) on the growth, yield and quality of trees in a Scots pine (Pinus sylvestris L.) stand. A long-term field experiment (25 years) was measured in 5-year periods and the further development was simulated with growth and yield models to final cuttings using alternative rotation periods of 55–85 years. The measurements included also the exact location and type of technical defects detected on all trees in the experimental plots. The measured volume increment per unit area during the study period, 25 years after the early thinning stage was the lowest in the plots thinned from below, and the highest in the plots thinned from above or in the delayed thinning plots. However, the largest volume of saw logs during the whole rotation of 80 years was yielded after early first thinning according to the quality. The largest volume of very high-quality butt logs was produced by pruning connected with early thinning from above, and a smaller volume after early thinning according to stem quality but no after thinning from below or delayed first thinning. Without pruning an early quality thinning with one intermediate thinning was the most profitable thinning treatment in the Scots pine stand regardless the rotation length or the interest rate used. By interest rates of 1% and 2%, the optimal rotations were 80–85 years and 70 years respectively. A late thinning at the age of 60 year with long rotation was profitable only for the pruned pine stands with a low interest rate.

• Niemistö, Natural Resources Institute Finland (Luke), Natural resources, Kampusranta 9 C, FI-60320 Seinäjoki, Finland E-mail: pentti.niemisto@luke.fi
• Kilpeläinen, Natural Resources Institute Finland (Luke), Production systems, Yliopistokatu 6, FI-80100 Joensuu, Finland E-mail: harri.kilpelainen@luke.fi
• Poutiainen, Oulu E-mail: eero1.poutiainen@dnainternet.net

• Fahlvik, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: nils.fahlvik@slu.se
• Ekö, Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences, P.O. Box 49, SE-230 53 Alnarp, Sweden E-mail: per.magnus.eko@slu.se
• Petersson, StoraEnso Skog AB, Åsgatan 22, SE-791 80 Falun, Sweden E-mail: nils.petersson@storaenso.com

• Niemistö, Finnish Forest Research Institute, Parkano Unit, FI-39700 Parkano, Finland E-mail: pentti.niemisto@metla.fi

• Turtiainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: marjut.turtiainen@uef.fi
• Miina, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jari.miina@metla.fi
• Salo, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kauko.salo@metla.fi
• Hotanen, Finnish Forest Research Institute, Joensuu Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: juha-pekka.hotanen@metla.fi

• Manninen, Agrifood Research Finland MTT, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: outi.h.manninen@mtt.fi
• Peltola, Agrifood Research Finland MTT, Eteläranta 55, FI-96300 Rovaniemi, Finland E-mail: rainer.peltola@mtt.fi

• Nilsson, Swedish University of Agricultural Sciences (SLU), Southern Swedish Forest Research Centre, Alnarp, Sweden E-mail: urban.nilsson@slu.se
• Elfving, SLU, Forest Ecology and Management, Umeå, Sweden E-mail: be@nn.se
• Karlsson, SLU, Unit of Field Based Research, Asa, Sweden E-mail: kk@nn.se

• Turtiainen, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: marjut.turtiainen@uef.fi
• Salo, Finnish Forest Research Institute, Joensuu Research Unit, Joensuu, Finland E-mail: ks@nn.fi
• Saastamoinen, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: os@nn.fi

• Jacobson, Skogforsk, Uppsala Science Park, SE-75183 Uppsala, Sweden E-mail: staffan.jacobson@skogforsk.se
• Pettersson, Skogforsk, Uppsala Science Park, SE-75183 Uppsala, Sweden E-mail: fp@nn.se

• Sikström, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: ulf.sikstrom@skogforsk.se
• Almqvist, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: ca@nn.se
• Jansson, Skogforsk (The Forestry Research Institute of Sweden), Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: gj@nn.se

• Tulokas, Centre for Timber Engineering, Edinburgh Napier University, 10 Colinton Road, Edinburgh EH10 5DT, UK E-mail: tomi.tulokas@lut.fi
• Tannous, School of Engineering and the Built Environment, Edinburgh Napier University, 10 Colinton Road, Edinburgh EH10 5DT, UK E-mail: jt@nn.uk

• Weiskittel, School of Forest Resources, University of Maine, Orono, ME 04469, USA E-mail: aaron.weiskittel@umit.maine.edu
• Kenefic, U.S. Forest Service, Northern Research Station, Bradley, ME 04411, USA E-mail: lsk@nn.us
• Seymour, School of Forest Resources, University of Maine, Orono, ME 04469, USA E-mail: rss@nn.us
• Phillips, School of Forest Resources, University of Maine, Orono, ME 04469, USA E-mail: lmp@nn.us

• Viherä-Aarnio, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: anneli.vihera-aarnio@metla.fi
• Velling, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: pv@nn.fi

• Huuskonen, University of Helsinki, Department of Forest Ecology, Helsinki, Finland E-mail: saija.huuskonen@helsinki.fi
• Hynynen, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: jh@nn.fi
• Ojansuu, Finnish Forest Research Institute, Vantaa Research Unit, Vantaa, Finland E-mail: ro@nn.fi

• Huuskonen, University of Helsinki, Dept. of Forest Ecology, P.O. Box 27, FI-00014 University of Helsinki, Finland E-mail: sh@nn.fi
• Hynynen, The Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jh@nn.fi

• Kojola, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: soili.kojola@metla.fi
• Penttilä, Finnish Forest Research Institute, Vantaa Research Centre, P.O. Box 18, FIN-01301 Vantaa, Finland E-mail: tp@nn.fi
• Laiho, University of Helsinki, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland E-mail: rl@nn.fi

• Varmola, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland E-mail: martti.varmola@metla.fi
• Salminen, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland E-mail: hs@nn.fi
• Timonen, The Finnish Forest Research Institute, Rovaniemi Research Station, P.O.Box 16, FIN-96301 Rovaniemi, Finland E-mail: mt@nn.fi

• Ihalainen, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: marjut.ihalainen@joensuu.fi
• Salo, The Finnish Forest Research Institute, Joensuu Research Centre, P.O. Box 68, FIN-80101 Joensuu, Finland E-mail: ks@nn.fi
• Pukkala, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland E-mail: tp@nn.fi

• Hoen, Agricultural University of Norway, Dept. of Forest Sciences, P.O. Box 5044, N-1432 Ås, Norway E-mail: hans.hoen@isf.nlh.no
• Eid, Agricultural University of Norway, Dept. of Forest Sciences, P.O. Box 5044, N-1432 Ås, Norway E-mail: te@nn.no
• Økseter, Agricultural University of Norway, Dept. of Forest Sciences, P.O. Box 5044, N-1432 Ås, Norway E-mail: po@nn.no

• Persson, Högskolan Dalarna, S-781 88 Borlänge, Sweden E-mail: bpn@du.se

• Ståhl, College of Dalarna, CITU Centre for Industrial Technology and Development, S-781 88 Borlänge, Sweden E-mail: esl@du.se

The coverage of bilberry (Vaccinium myrtillus L.) was modelled as a function of site and stand characteristics using the permanent sample plots of the National Forest Inventory (NFI) (Model 1). The sample sites consisted of mineral soil forests as well as fells and peatland sites. Annual variation in the bilberry yield (Model 2) was analysed based on measurements over 2001–2014 in the permanent sample plots (so-called MASI plots) in various areas of Finland. We derived annual bilberry yield indices from the year effects of Model 2 and investigated whether these indices could be used to estimate annual variation in bilberry crops in Finland. The highest bilberry coverage was found in mesic heath forests and fell forests. On peatlands the coverage was, on average, lower than on mineral soil sites; the peatland sites with most bilberry coverage were meso-oligotrophic and oligotrophic spruce mires and oligotrophic pine mires. Our bilberry yield indices showed similar variation to those derived from the mean annual berry yields reported and calculated earlier using the MASI plots; the correlation between the indices was 0.795. This approach to calculating annual berry yield indices is a promising way for estimating total annual bilberry yields over a given period of time. Models 1 and 2 can be used in conjunction with the Miina et al.’s (2009) bilberry yield model when bilberry coverage, average annual yield and annual variation in the yield are to be predicted in forest planning.

• Turtiainen, University of Eastern Finland, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: marjut.turtiainen@uef.fi
• Miina, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Box 68, FI-80101 Joensuu, Finland E-mail: jari.miina@luke.fi
• Salo, Natural Resources Institute Finland (Luke), Bio-based Business and Industry, Box 68, FI-80101 Joensuu, Finland E-mail: kauko.salo@luke.fi
• Hotanen, Natural Resources Institute Finland (Luke), Management and Production of Renewable Resources, Box 68, FI-80101 Joensuu, Finland E-mail: juha-pekka.hotanen@luke.fi

• Lundqvist, Deparment of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden E-mail: lars.lundqvist@slu.se
• Spreer, Sveaskog Förvaltnings AB, Ljusdal, Sweden E-mail: susanne.spreer@sveaskog.se
• Karlsson, Field Research Unit, Swedish University of Agricultural Sciences, Siljansfors, Sweden E-mail: christer.karlsson@slu.se