Harri Kilpeläinen

An approach for examining the effects of preferential uncertainty on the contents of forest management plan at stand and holding level

A proper forest planning process includes the assessment of the decision-makers’ preferences concerning the future forest use. For some owners, it may be a difficult task to express their preferences exactly and in the form that is required for planning calculations. This study presents a new kind of approach for analyzing the effects of preferential uncertainty. The approach consists of examination of the differences in the actual decision variables in forest planning, i.e. selected treatments for stands between holding-level forest plans. In example calculations, the preferential uncertainty was examined from three different viewpoints: the uncertainty in the weights of the objective variables; the uncertainty in the partial utility function; and the combination of these two uncertainty sources. One thousand preference realizations were generated for each of these uncertainty sources. More than one treatment schedules are proposed for stands that are affected by preferential uncertainty. These stands were detected from among the resulting set of 1,000 forest plans. With this done, two potential decision-making strategies, an adaptive behavior strategy and a threshold proportion strategy, were applied as guides in decision-making for stands, which have more than one treatment alternative selected in the produced optimal forest plans. The adaptive behavior technique required that the forest owner select one treatment alternative for at least one stand that has more than one proposed treatment alternative. The treatment alternatives having frequencies exceeding the given threshold frequency were all accepted simultaneously in the threshold strategy. The main benefit of the approach is to present the effects of uncertainties in a way that can be easily understood by the actual decision-makers. It is a promising tool for practical decision-making situations because at least Finnish non-industrial private forest owners quite often focus on making stand-level forest management decisions. It is also suitable for examinations of other uncertainty sources such as timber prices or inventory data.

Constructing forest plans interactively based on owner-driven evaluation of the holding- and stand-level alternatives

In this study, an interactive forest planning process corresponding to the practical demands was developed and further tested in a challenging forest planning situation in northeastern Finland. The process includes prior preparation of alternative stand-level treatments and a small amount of holding-level forest plans; an interactive planning session consisting of the primary choice of the forest owners profile; the owners selection of the best holding-level plan; and finally a local improvement of this plan. The method as a whole aims to bridge the gap between the prevailing planning culture that has developed for private forest planning over three decades in Finland and the planning approach suggested by multiobjective forest planning theory. The usability and characteristics of the process were evaluated through an exercise set given to both forestry students and forest professionals. Tests of the process indicated, among other things, that comparison particularly of stand-level alternatives and offering owners the possibility to make changes and truly affect the end-result of the planning process are seen as important characteristics of the process.

Description and evaluation of Prehas software for pre-harvest assessment of timber assortments

Prehas is a decision support tool for assessing the amount and value of harvestable timber, including predictions of timber assortment recovery, length-diameter distribution of logs, and value recovery. Predictions are based on previously collected cut-to-length harvester stem data (stm-data), which is stored by the software as a stem database, and a non-parametric k-MSN method. Using easily achievable search variables, Prehas produces stem group estimates, including stem diameters at 10 cm intervals for each stem. This stem group can be bucked using a bucking simulator (included in Prehas) to achieve the estimates of timber assortment recovery, value, and log length-diameter distribution. Prehas has three versions: Prehas-International, Prehas-Scotland, and Prehas-Finland, of which the latter is also capable of predicting the technical quality of stems to be used in bucking simulations. The software includes routines for the user to collect and save their own stm-data representing local forests. This article describes the structure and methodology of Prehas. To assess the performance of Prehas, a test was conducted using the empirical data collected for measurements of dimensions and quality of trees from sample plots. The data consisted of 61 stands located in south-eastern Finland including commercial clear-cutting stands in private and state forests. Prehas’s predictions were slightly more reliable than those of the compared timber assortment recovery regression models for southern Finland.

Integrating bilberry yields into regional long-term forest scenario analyses

ABSTRACT In many areas, picking wild berries constitutes an important forest commodity offering food, recreational services, and revenues. Intensified forest management has negatively affected bilberry yields. In this study, regional-level scenario analyses were conducted to investigate the effects of four approaches to the inclusion of bilberry yields on the economics, management, and resulting forest structures in North Karelia. The current approach ignoring bilberries resulted in decreasing bilberry yields and increasing younger forests. When bilberries were valued at market price (1.72 € kg−1), bilberry yields still decreased despite the fact that forest management were slightly modified to favour bilberry. Adding non-declining sustainability constraints to bilberry yields resulted in a slightly lower total net present value of timber and bilberry since forest management favoured longer rotation lengths, which increased bilberry yields. Similar effects occurred when the bilberry price was tripled to include the implicit ecosystem benefits of bilberries. When forests were managed only for bilberries (timber zero-priced), bilberry yields started to increase immediately resulting in 1.5-fold difference in 50 years as compared to timber only scenario. In conclusion, managing forests for both timber and bilberry production has rather minor effects on economics, but it can have clear positive effect on bilberry yields.

Hakkuukonemittauksen tyvifunktio männyn tyviosan tilavuuden määrityksessä

Tiivistelmä Hakkuukonemittauksessa tyvipölkkyjen tyviosan läpimitat määritetään laskennallisesti puulajikohtaisilla tyvifunktioilla. Tyviosalla tarkoitetaan 1,3 metrin pituista rungonosaa kaatosahauksesta lähtien. Tämän tutkimuksen tavoitteena oli tarkastaa ja tarvittaessa korjata hakkuukonemittauksessa käytettävä männyn tyvifunktio. Tutkimukseen valittiin 33 eri puolella Suomea sijaitsevaa mäntymetsikköä, joista valittiin 825 koepuuta. Koepuiden mittauksia tehtiin metsässä, ja hakkuiden jälkeen koepuiden tyvipölkyille tehtiin mittauksia kuudella eri tehtaalla. Koetyvipölkkyjen tyviosien vertailutilavuudet määritettiin upotusmittauksella. Tyvifunktioissa tyviosan suhteellinen muoto muuttuu tyvipölkyn järeyden, siis 130 senttimetrin etäisyydeltä kaatosahauksesta mitatun läpimitan, mukaan. Tässä tutkimuksessa tyvifunktio tuotti pienillä puilla suurempia, ja suurilla puilla pienempiä läpimittoja koepuiden tyviosista saksimittauksella mitattuihin läpimittoihin verrattuna. Koetyvipölkkyaineistossa tyviosan suhteellinen muoto ei muuttunut pölkkyjen järeyden mukaan, vaan oli likimäärin vakio. Tyvifunktion korjaus muodostui kahdesta vaiheesta, niin sanotuista oikaisukorjauksesta ja tasokorjauksesta. Tyvifunktion oikaisukorjaus tehtiin koepuiden tyviosista saksimittauksella mitattujen läpimitta-aineistojen perusteella. Näin korjatun tyvifunktion perusteella määritetyt koetyvipölkkyjen tyviosan tilavuudet olivat noin viisi prosenttia tyviosien upotustilavuuksia suurempia kaikilla järeyksillä. Edelleen tyvifunktiolle tehtiin tasokorjaus siten, että tyvifunktion perusteella määritetyt tyviosan tilavuudet vastasivat upotustilavuutta. Tyvifunktion korjauksen vaikutus sillä määritettyyn tyviosan tilavuuteen oli pienillä noin 50 litran rungoilla (rinnankorkeusläpimitta noin 10 senttimetriä) noin –8,5 prosenttia ja suurilla noin 1750 litran rungoilla (rinnankorkeusläpimitta noin 45 senttimetriä) noin –2,9 prosenttia. Kun tyvifunktion korjaus suhteutetaan koko rungon tilavuuksiin, olivat vastaavat osuudet noin –2,3 ja –0,4 prosenttia. Kun korjaus suhteutetaan Suomen kokonaishakkuukertymäarvioissa esitettyihin järeysluokkien osuuksiin, on kokonaisvaikutus suuntaa-antavasti noin yhden prosentin vähennys männyn kokonaistilavuudessa.

Combined production of sawn timber and firewood billets at a birch sawmill in Finland: a simulation approach.

Abstract Growing markets for chopped firewood have created alternative uses for the by-products of sawmills. Based on empirical data and simulated results, the potential of birch (Betula pendula Roth, Betula pubescens Ehrh.) from commercial thinnings for combined industrial production of sawn timber and firewood billets was investigated. In the simulations, different sawing patterns were used for logs intended to combine production of sawn timber and billets for chopped firewood (‘sawlogs’), and for logs intended only to firewood production (‘firewood logs’). Finally, economical feasibility analysis was done concerning the differences between the sawmills’ traditional business concept and the novel concept combining sawn wood and firewood production. The bucking results for the volume yield of different timber assortments varied only slightly between the different bucking options, i.e. the combinations of timber assortments. The main differences in the volumes of timber assortments were due to the stand type where the birch trees were sampled (planted, naturally regenerated, mixed birch–spruce). In the sawing procedure, the output of sawn timber varied between 24% and 42% of the log volume in the sawlogs, depending on the log diameter class. As the volume yield of sawn timber and firewood billets was counted together in the case of sawlogs, the log consumption was c. 1.75 m3 of roundwood per 1 m3 of sawn timber and firewood billets. In the case of the firewood logs, the log consumption rate was considerably lower, only c. 1.35. The economic calculations showed that using the firewood approach in sawing may increase the net added value of products by €1.9–5.4 m−3 of logs, depending on their diameter class. As a conclusion, parallel production of sawn timber and firewood from logs from the first and second commercial thinning of birch-dominated stands is a concept that could work as an alliance between a sawmiller and a firewood entrepreneur. The concept could be competitive compared with both traditional sawmilling and production of chopped firewood.