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Scots pine (Pinus sylvestris L.) is the most widely distributed pine species in the world. However, it is sensitive to sudden changes in the environment because of its long lifespan and slow adaptation through changes in its DNA sequence. Epigenetic modifications, such as DNA methylation, affect the regulation of genes and can contribute to the environmental adaptation and evolution of plants. The Scots pine is a favorable species to study epigenetic adaptation since epigenetic changes can help trees to adapt to environmental changes more quickly. The aim of this study was to improve the current understanding of genes involved in the adaptation of trees by investigating the regulation and expression of these genes. This thesis explored the effects of variation in gene expression and DNA methylation on the adaptation of Scots pine. Firstly, differences in growth characteristics and gene expression were studied in Scots pine seedlings of southern and northern origins under different light conditions. Secondly, variation in DNA methylation and gene expression levels were examined in adaptation-related genes between three Scots pine populations. The two tissue types of Scots pine seed were employed, namely embryo and megagametophyte, which have different functions and mechanisms of inheritance. The results showed that there were differences in the expression levels of the studied genes between Scots pine seedlings of southern and northern origins under different light conditions, as well as between seeds of southern and northern Scots pine populations. The data indicates that blue light and deficiency of far-red light limit the growth of Scots pine especially in the northern populations. It was concluded that differential gene expression and DNA methylation variation contribute to the growth and adaptation of Scots pine. Furthermore, based on the results, differences in gene expression levels in natural populations can be due to changes in DNA methylation. A connection in DNA methylation levels was observed between embryos and megagametophytes of the seeds, suggesting that epigenetic changes are inherited from the maternal parent tree. All in all, this thesis sheds light on the epigenetic regulation and expression variation of adaptation-related genes in forest trees. Tiivistelmä Metsämänty, eli mänty (Pinus sylvestris L.), on laajimmalle levinnyt mäntylaji. Mänty on herkkä äkillisille ympäristössä tapahtuville muutoksille, koska sillä on pitkä sukupolven väli ja sen sopeutuminen on hidasta DNA-sekvenssissä tapahtuvien geneettisten muutosten kautta. Epigeneettiset muutokset, kuten DNA:n metylaatio, vaikuttavat geenien säätelyyn ja niillä voi olla tärkeä rooli kasvien sopeutumisessa ja evoluutiossa. Mänty on otollinen laji tutkia epigeneettistä sopeutumista, sillä epigeneettiset muutokset voivat auttaa puita sopeutumaan nopeammin ympäristömuutoksiin. Tämän tutkimuksen tarkoituksena oli parantaa nykyistä ymmärrystä metsäpuiden sopeutumiseen osallistuvista geeneistä tarkastelemalla niiden säätelyä ja ilmentymistä. Väitöskirjassani tutkittiin männyn sopeutumisen aikana tapahtuvaa geenien ilmentymisen ja DNA:n metylaation muuntelua. Ensimmäisessä osatutkimuksessa selvitettiin eteläistä ja pohjoista alkuperää olevien männyn taimien kasvun ja geenien ilmentymisen eroja erilaisissa valo-olosuhteissa. Toisessa ja kolmannessa osatutkimuksessa tutkittiin männyn siemenen kahta solukkoa eli alkiota ja megagametofyyttiä, joilla on erilainen tehtävä ja periytymismekanismi. Selvitimme, miten DNA:n metylaatiotasot ja geenien ilmentymisasteet eroavat tutkituissa sopeutumisgeeneissä eri puolilla Suomea olevissa mäntypopulaatioissa. Väitöskirjan tulokset osoittivat, että tutkittujen geenien ilmentymistasot erosivat pohjoista ja eteläistä alkuperää olevissa männyntaimissa erilaisissa valo-olosuhteissa sekä pohjoisten ja eteläisten mäntypopulaatioiden välillä. Tutkimusaineisto osoitti, että sininen valo sekä kaukopunaisen valon puute rajoittivat männyn kasvua etenkin pohjoisissa populaatioissa. Tutkimustulosten perusteella voi päätellä, että erot geenien ilmentymisessä sekä DNA:n metylaatiotasoissa vaikuttavat männyn kasvukykyyn ja sopeutumiseen. Luonnonpopulaatioissa havaittujen geenien ilmentymiserojen taustalla saattavat olla DNA:n metylaatiomuutokset. Männynsiementen alkioiden ja megagametofyyttien DNA:n metylaatiotasoissa huomattiin yhteys, mikä viittasi siihen, että epigeneettiset muutokset periytyvät emopuulta jälkeläisille. Kaiken kaikkiaan, tämä väitöskirja tuo uutta tietoa sopeutumiseen liittyvien geenien epigeneettisestä säätelystä ja ilmentymisen muutoksista metsäpuilla.

Suomessa on havaittu ensimmäistä kertaa puille toisinaan kohtalokasta etelänversosurmaa. Taudin aiheuttaa havuparikas-sieni. Tautia esiintyy enimmäkseen männyillä, mutta myös muilla havupuilla. Uusi opportunistinen tuhonaiheuttaja saattaa saada nyt enemmän elintilaa Suomessa, lisääntymällä puissa joiden juuristo on ollut jo valmiiksi männynjuurikäävän tai kuivuuden heikentämä. Suomessa etelänversosurma havaittiin, kun syyskuussa Lounais-Suomesta löytyi kuolleita mäntyjä useasta kohteesta. Yhdellä Uudenkaupungin lähellä sijaitsevalla kohteella yhdeksi tuhoajaksi osoittautui myös etelänversosurma. Ilmastonmuutos ja etenkin lisääntynyt kuivuus edesauttaa havuparikas-sienen muuttumista taudinaiheuttajaksi. Havuparikasta on aiemmin löydetty Suomesta saprotrofina männyn kävyistä, sekä piilevänä vuosikasvaimista. Nyt havuparikasta on ensimmäistä kertaa löydetty Suomessa mäntyjen kuolemien yhteydessä. Sienen levinneisyys ja runsaus pitäisi selvittää, sekä taudin puhkeamista on syytä tutkia, jotta mahdollinen uhka Suomen metsille selviää.

Three geometrical thinning methods were tested and compared with conventional selective thinning. The geometrical harvesting methods were two boom corridor (BCT1, BCT2) and one machine corridor (MCT) methods. In the BCT-methods all trees were removed from 1.5 m wide and 10 m deep corridors which were placed on both sides of the trip road at each operational stop. In BCT1, three corridors were made on both sides of the machine at various angles to the travel direction at each operational stop at 10 m intervals. In BCT2, corridors were made only at a 60° angle and 3 m intervals. In the MCT trees were removed only from the front of the machine. BCT2 had the highest productivity in harvesting, forwarding and overall productivity (3.96 m3/E0). The selective thinning was even in harvesting but lower in forwarding and overall productivities (3.82 m3/E0). BCT1 productivity was lower in harvesting and forwarding with 3.68 m3/E0 overall productivity. In the MCT the dense treetops in front of the machine oft...

Human-induced fragmentation affects forest continuity, i.e. availability of a suitable habitat for the target species over a time period. The dependence of wood-inhabiting fungi on landscape level continuity has been well demonstrated, but the importance of local continuity has remained controversial. In this study, we explored the effects of local forest continuity (microhabitat and stand level) on the diversity of wood-inhabiting fungi on standing dead trunks of Scots pine (Pinus sylvestris L.). We studied species richness and community composition of decomposers and Micarea lichens on 70 trunks in 14 forests in central Finland that differed in their state of continuity. We used dendrochronological methods to assess the detailed history of each study trunk, i.e. the microhabitat continuity. The stand continuity was estimated as dead wood diversity and past management intensity (number of stumps). We recorded 107 species (91 decomposers, 16 Micarea lichens), with a total of 510 occurrences. Using generalized linear mixed models, we found that none of the variables explained decomposer species richness, but that Micarea species richness was positively dependent on the time since tree death. Dead wood diversity was the most important variable determining the composition of decomposer communities. For Micarea lichens, the community composition was best explained by the combined effect of years from death, site and dead wood diversity. However, these effects were rather tentative. The results are in line with those of previous studies suggesting the restricted significance of local forest continuity for wood-inhabiting fungi. However, standing dead pines that have been available continuously over long periods seem to be important for species-rich communities of Micarea lichens. Rare specialists (e.g. on veteran trees) may be more sensitive to local continuity, and should be at the center of future research. peerReviewed

Non

One-step absolute solvent-free acid-catalyzed mechanical depolymerization of pine sawdust (PSD) and commercially available α-cellulose to water-soluble sugars was carried out using ball milling. For comparison purposes, the commonly reported “solvent-free” mechanocatalytic depolymerization of lignocellulose method, which normally involves three steps (acid impregnation in solvent, vacuum drying, and mechanical depolymerization of lignocellulose), was performed. The 3,5-dinitrosalicylic acid (DNS) method was used to measure the total reducing sugar (TRS) of the obtained sugar solution, and major monosaccharides in the solution were analyzed by capillary electrophoresis (CE). More than 90% of the PSD became water-soluble through milling. Furthermore, most of the PSD was converted into TRS in approximately 30 min, and the highest TRS yield obtained was 31%, based on the dry mass. Interestingly, the TRS solutions obtained from the processed PSD were much darker than those obtained from α-cellulose due to the chromophores that formed during the depolymerization of lignin.

To date, plant endophytic bacteria have mainly been studied in roots of crop plants. However, shoot-associated endophytes are less diverse than root-associated ones. Hence, endophytic bacteria of plant shoots evolved different traits, than root colonizers, especially with types of host tissues infected and patterns of growth and development. This study found Methylobacterium extorquens colonized pine seedlings similarly to stem-colonizing rhizobia of other plants. M. extorquens DSM13060 was isolated from meristematic cells in shoot tip cultures of Scots pine (Pinus sylvestris L.). M. extorquens infected the plant stem through epidermis or stomatal apertures, forming infection pockets in the root and stem epidermis, or cortex. Post-infection, thread-like infection structures passed through the endoderm, invading vascular tissues. This led to systemic colonization of above and below ground-parts, observed in in vitro grown Scots pine. A novel mechanism enabling development of endophyte-host symbiosis is discovered within the M. extorquens — Scots pine model. This mechanism involves ability of M. extorquens to produce polyhydroxybutyrates (PHB) to protect itself from host-induced oxidative stress during infection. Upon initial colonization on the host surface, M. extorquens DSM13060 consumes methanol as a carbon source, using it to biosynthesize PHB. PHB are then degraded, upon host infection, by PHB depolymerases (PhaZ) to yield methyl-esterified 3-hydroxybutyrate oligomers. These oligomers have substantial antioxidant activity towards host-induced oxidative stress, enabling the bacterium to bypass host defenses and colonize further tissues. The bacteria can also store PHBs for future protection. The capacity for PHB production and, thus, protection from oxidative stress, is discovered in a wide taxonomic range of bacteria. This study also shows meristematic endophytes are important in growth and development of their hosts. Unlike many bacterial root endophytes, M. extorquens DSM13060 does not induce plant growth through hormones. However, this bacterium can colonize the interior of living host cells, where it aggregates around the nucleus of the host plant. M. extorquens DSM13060 genome encodes nucleomodulins, eukaryotic-like transcription factors, which may intervene in host transcription and metabolism. Tiivistelmä Kasvin sisällä elävien endofyyttisten bakteerien tutkimus on perinteisesti keskittynyt viljelykasveihin ja niiden juuristoon. Kasvien maanpäällisissä versoissa elävät endofyytit eroavat merkittävästi juuriston bakteereista lajirikkauden suhteen. Versoissa eläville bakteereille on todennäköisesti kehittynyt erilaisia sopeumia kuin juuriston endofyyttilajeille. Endofyyttinen Methylobacterium extorquens DSM13060 elää männyn silmujen kasvusolukossa lisäten isäntäkasvin kasvua. Tässä tutkimuksessa M. extorquens -bakteerin todettiin siirtyvän männyn taimiin samoja mekanismeja käyttäen kuin Rhizobium -suvun typensitojabakteerit. Metylobakteeri tunkeutui isäntäkasviin aktiivisesti soluseinien läpi tai varren ilmarakojen kautta muodostaen mikropesäkkeitä juuren ja varren pinnoille, sekä infektiotaskuja kuorisolukkoon. Bakteeri eteni infektiolankojen avulla endodermin ohi johtosolukoihin, mikä mahdollisti bakteerin siirtymisen muualle taimeen. M. extorquens käytti kasvin pinnalla runsaana olevaa metanolia hiilenlähteenään, varastoiden sen solujen sisäiseksi polyhydroksibutyraatti (PHB) polymeeriksi. Infektion myöhemmissä vaiheissa bakteeri hajotti varastoidun polymeerin PHB-depolymeraasientsyymien (PhaZ) avulla lyhyiksi rasvahappoketjuiksi. Nämä metyloidut 3-hydroksibutyraatin oligomeerit suojasivat bakteeria isäntäkasvin puolustuksen tuottamilta happiradikaaleilta mahdollistaen infektion etenemisen. Tutkimuksessa saatujen tulosten perusteella endofyytin solunsisäinen energiavarasto, PHB, toimii pelkistävänä varastona ympäristön hapettavaa stressiä vastaan. Löytö osoitti uudenlaisen antioksidatiivisen puolustumekanismin, joka on levinnyt laajalle bakteerikunnassa ja liittyy yleisesti bakteerien kykyyn sietää vaikeita olosuhteita. Toisin kuin useat juurissa elävät bakteeriendofyytit, M. extorquens ei lisää isäntäkasvin kasvua tuottamalla kasvihormoneja. Bakteeri kykenee elämään männyn elävien solujen sisällä tumien läheisyydessä. M. extorquens DSM13060 genomi sisältääkin useita geenejä, jotka koodaavat nukleomoduliineja, eukaryoottisolujen säätylytekijöiden kaltaisia entsyymejä, joiden avulla bakteeri todennäköisesti vaikuttaa isäntäkasvin aineenvaihduntaan. Vastaavaa vaikutusmekanismia ei ole aikaisemmin kuvattu endofyyteillä. Tutkimus korostaa aiemmin tuntemattomien meristemaattisten bakteeriendofyyttien merkitystä isäntäkasvin kasvussa ja erilaistumisessa.

Wood is an essential material that has many applications in the fields of engineering and especially in the forest industry, which is particularly important in Fennoscandia. Among the various modification methods for wood, thermal modification has grown substantially over the past decades. It is an environmentally friendly method for increasing the lifetime and usability of timber. The aim of this thesis is to characterize the properties of thermally modified wood as well as to obtain new information on the changes taking place in pinewood due to the thermal modification process. Several NMR methods were used to gain information on the effect of thermal modification on the microstructure and moisture components of Pinus sylvestris pinewood. Pinewood samples thermally modified at different temperatures were studied and compared to corresponding unmodified wood samples. Diffusion of water and methane was studied using pulsed-field-gradient stimulated-echo measurements to determine the highly anisotropic size distribution of pores in different cell structures of pinewood. NMR cryoporometry and relaxometry measurements were conducted to gain information on the amounts and environments of both the bound and free water absorbed into the wood samples. Cryoporometry measurements resulted in an upper limit value for the size of bound water sites and the combination of cryoporometry and relaxometry data enabled the size determination of cell wall micropores. Magnetic resonance imaging was used to visualize the spatial distribution of absorbed free water in the studied samples. Together these methods give a broad overall picture of the effects of the modification process. The results of this work give new insight into the microstructure of thermally modified pinewood and its relationship to moisture, which is of importance for both wood science as well as industry. The applicability of the NMR techniques used here to the study of wood is also proven in this work. Using the techniques developed, it is possible to determine the optimal modification temperature, which is high enough to obtain the desired effects, but low enough not to destroy the microstructure of wood. Tiivistelmä Puuta pystytään hyödyntämään useilla eri aloilla ja se on materiaalina tärkeä etenkin Fennoskandiassa merkittävälle metsäteollisuudelle. Useiden erilaisten puun käsittelymenetelmien joukossa lämpökäsittely on kasvattanut voimakkaasti suosiotaan viime vuosikymmeninä. Kyseessä on ympäristöystävällinen menetelmä, jolla voidaan pidentää puun käyttöikää sekä käytettävyyttä erilaisissa sovelluskohteissa. Tämän väitöskirjan päämääränä on ollut lämpökäsitellyn puun ominaisuuksien tutkiminen ja uuden tiedon saaminen puussa lämpökäsittelyprosessin myötä tapahtuvista muutoksista. Työssä käytettiin useita eri NMR-menetelmiä lämpökäsitellyn mäntypuun (Pinus sylvestris) mikrorakenteen sekä puussa olevan kosteuden aiheuttamien vaikutusten tutkimiseksi. Työssä tutkittiin eri lämpötiloissa käsiteltyjä mäntypuunäytteitä, joita verrattiin vastaaviin käsittelemättömiin näytteisiin. Veden ja metaanin diffuusiota tutkittiin PGSTE-menetelmällä puun erittäin anisotrooppisen solurakenteen sisältämien huokosten mittojen määrittämiseksi. NMR-kryoporometria- ja -relaksometriamittaukset antoivat tietoa puuhun imeytyneen sidotun ja vapaan veden määrästä ja esiintymisympäristöstä. Kryoporometria-mittausten tuloksista saatiin yläraja sidotun veden esiintymispaikkojen koolle, ja kryoporometria- ja relaksometriamittausten tuottaman tiedon yhdistäminen mahdollisti soluseinämien mikrohuokosten koon määrittämisen. Magneettikuvausta käytettiin näytteisiin absorboituneen veden avaruudellisen jakauman määrittämiseen. Käytetyt menetelmät tarjoavat laajan kokonaiskuvan lämpökäsittelyprosessin vaikutuksista puulle. Tämän työn tulokset antavat puutiedettä ja -teollisuutta hyödyttävää uutta tietoa lämpökäsitellyn männyn mikrorakenteesta sekä sen suhteesta kosteuteen. Väitöskirja myös osoittaa käytettyjen NMR-menetelmien soveltuvan hyvin puun tutkimiseen. Tämän tutkimuksen myötä kehitettyjen menetelmien avulla voidaan määrittää mm. optimaalinen lämpökäsittelylämpötila, joka on riittävän korkea haluttujen ominaisuuksien kannalta aiheuttamatta kuitenkaan puun mikrorakenteen hajoamista.

Seloste artikkelista: Havimo, M., Rikala, J., Sirvio, J. & Sipi, M. 2009. Tracheid cross-sectional dimensions in Scots pine (Pinus sylvestris) – distributions and comparison with Norway spruce (Picea abies). Silva Fennica 43 (4) : 681–688.

Cell wall thickness and tracheid radial and tangential diameter are important characteristics in papermaking. These fibre cross-sectional dimensions affect paper properties such as light scattering, and tear and tensile indexes. In the authors’ previous article, the mean values and distributions of tracheid cross-sectional dimensions were obtained for Norway spruce (Picea abies). This article characterises the cross-sectional tracheid properties of Scots pine (Pinus sylvestris) using exactly the same methodology as in the previous study on Norway spruce, which enables the comparison between the tree species. The distributions for Scots pine cell wall thickness and tracheid radial diameter were similar: a narrow peak due to earlywood tracheids, and a wide peak due to latewood tracheids. The tangential diameter distributions for Scots pine were very similar in both earlywood and latewood, having one wide peak. Also, the distributions in whole stem, top pulpwood and sawmill chip assortments were quite similar. The differences between Scots pine and Norway spruce tracheid cross-sectional dimensions were fairly marginal. This is at least the case when comparing large tracheid populations, in which differences tend to even out. The situation may be different on a more detailed level of observation, for example, when individual annual rings in the different tree species are compared.

The purpose of this study was to compare the Weibull distributions estimated for the entire growing stock of a stand and separately for Scots pine ( L.) and Norway spruce ( (L.) H. Karst.) in describing the basal area diameter distributions in mixed stands. The material for this study was obtained by measuring 553 stands located in eastern Finland. The parameters of the Weibull distribution were estimated using the method of maximum likelihood. The models for these parameters were derived using regression analysis. Also, some parameter models from previous studies were compared with the measured distribution. The obtained distributions were compared using the diameter sums of the entire growing stock, diameter sums by tree species and of the sawtimber part of the growing stock. The results showed that far more accurate results were obtained when the distributions were formed using parameter models separately for the different tree species than when using parameter models for the entire growing stock. This was already true when considering the entire growing stock of the stand and especially when the results were examined by tree species. When the models for the entire growing stock were applied by tree species in relation to basal areas, the results obtained were overestimates for Norway spruce and underestimates for Scots pine. The models from earlier studies, where parameter models were estimated separately for tree species from the National Forest Inventory data, showed good fits also in regard to the data of this study.Pinus sylvestrisPicea abies

Three most promising protection methods of pine pulp wood stacks against the attacks of L. were compared. The methods were the covering of stacks by fibreglass-strengthened paper or twofold achrylene netting, removing the upper parts of stacks, and enhanced planning of the placement of the timber store using ARC/INFO GIS-software. was observed to strongly prefer the upper parts of the stacks: 90 % of the beetles occurred within 0.5 meters of the top of the stacks. Covering of the stacks decreased the attack density of , and the protection effect of covering was 80 %. Due to long transport distances and fragmentation of forest landscape the relocation of timber store was found to be an unsuitable method in the practical level. Also, taking into account the costs of the method, removing of the upper parts of stacks was considered to be the optimal solution.Tomicus piniperdaT. piniperdaT. piniperda

The effective heating values of the above and below ground biomass components of mature Scots pine (Pinus sylvestris), Norway spruce (Picea abies), downy birch (Betula pubescens), silver birch (Betula pendula), grey alder (Alnus incana), black alder (Alnus glutinosa) and trembling aspen (Populus tremula) were studied. Each sample tree was divided into wood, bark and foliage components. Bomb calorimetry was used to determine the calorimetric heating values. The species is a significant factor in the heating value of individual tree components. The heating value of the wood proper is highest in conifers. Broad-leaved species have a higher heating value of bark than conifers. The species factor diminishes when the weighted heating value of crown, whole stems or stump-root-system are considered. The crown material has a higher heating value per unit weight in comparison with fuelwood from small-sized stems or wholetrees. The additional advantages of coniferous crown material are that it is a non-industrial biomass resource and is readily available. The variability of both the chemical composition and the heating value is small in any given tree component of any species. However, lignin, carbohydrate and extractive content were found to vary from one part of the tree to another and to correlate with the heating value.

A process-oriented tree and stand growth model is extended to be applicable to the analysis of timber quality, and how it is influenced by silvicultural treatments. The tree-level model is based on the carbon balance and it incorporates the dynamics of five biomass variables as well as tree height, crown base, and breast height diameter. Allocation of carbon is based on the conservation of structural relationships, in particular, the pipe model. The pipe-model relationships are extended to the whorl level, but in order to avoid a 3-dimensional model of entire crown structure, the branch module is largely stochastic and aggregated. In model construction, a top-down hierarchy is used where at each step down, the upper level sets constraints for the lower level. Some advantages of this approach are model consistency and efficiency of calculations, but probably at the cost of reduced flexibility. The detailed structure related with the branching module is preliminary and will be improved when more data becomes available. Model parameters are identified for Scots pine ( L.) in Southern Finland, and example simulations are carried out to compare the development of quality characteristics in different stocking densities.Pinus sylvestris

The effects of precommercial thinning on the quantity and external quality of young Scots pine stands were examined over two 10-year periods in an experiment comprising five stands growing on sub-dry sites in Finnish Lapland, northern Finland. The thinning treatments applied resulted in stand densities of 625, 1111, 1600, 2500 and 4444 stems ha–1 and a no-treatment, unthinned plot with a randomised block lay-out of two or tree replications in each stand. The dominant height of the stands varied between 4 and 8 m at the time of thinning. The trees reacted only slightly to the increase in growing space during the first ten years following precommercial thinning. During the second 10-year period, increased growing space was reflected more clearly in diameter and volume increment. These reactions were more evident in stands thinned at an early stage. The increment of the thinnest 100–200 trees ha–1 in each treatment was poor. The results showed that when the main principle in precommercial thinning is to achieve even spacing, the remaining smallest trees fail to react positively to the increase in growing space. In other words, the target of precommercial thinning should be to concentrate the increment on the tallest trees, even though they are located in groups. The external quality of the trees in stands where precommercial thinning was carried out at a later stage was high, and the diameter of the thickest branch along the butt log remained under 20 mm. Branch diameter was greater in stands thinned at an early stage. The effect of precommercial thinning on branch diameter when comparing the extreme treatments averaged 5 mm. When the aim of stand management is to combine high quality and good yield in naturally regenerated Scots pine stands in northern Finland, precommercial thinning should not be carried out before the dominant height of 7–8 m. The intensity of precommercial thinning depends on the yield targets of the first commercial thinning. A spacing of 2500 stems ha–1 satisfies the requirements of both high quality and adequate yield.

To enhance the utilization of the wood, the sawmills are forced to place more emphasis on planning to master the whole production chain from the forest to the end product. One significant obstacle to integrating the forest-sawmill-market production chain is the lack of appropriate information about forest stands. Since the wood procurement point of view in forest planning systems has been almost totally disregarded there has been a great need to develop an easy and efficient pre-harvest measurement method, allowing separate measurement of stands prior to harvesting. The main purpose of this study was to develop a measurement method for pine stands which forest managers could use in describing the properties of the standing trees for sawing production planning. Study materials were collected from ten Scots pine stands (Pinus sylvestris) located in North Häme and South Pohjanmaa, in southern Finland. The data comprise test sawing data on 314 pine stems, dbh and height measures of all trees and measures of the quality parameters of pine sawlog stems in all ten study stands as well as the locations of all trees in six stands. The study was divided into four sub-studies which deal with pine quality prediction, construction of diameter and dead branch height distributions, sampling designs and applying height and crown height models. The final proposal for the pre-harvest measurement method is a synthesis of the individual sub-studies. Quality analysis resulted in choosing dbh, distance from stump height to the first dead branch (dead branch height), crown height and tree height as the most appropriate quality characteristics of Scots pine. Dbh and dead branch height are measured from each pine sample tree while height and crown height are derived from dbh measures by aid of mixed height and crown height models. Pine and spruce diameter distribution as well as dead branch height distribution are most effectively predicted by the kernel function. Roughly 25 sample trees seems to be appropriate in pure pine stands. In mixed stands the number of sample trees needs to be increased in proportion to the intensity of pines in order to attain the same level of accuracy.

Possibilities of distance-independent and -dependent competition indices to describe the competition stress of an individual tree was studied in southern Finland. Five half-sib open-pollinated families and one check lot of Scots pine (Pinus sylvestris L.) was used as study material in order to analyse competitive interactions of crown form and stand density variation. Almost all competition indices correlated strongly with radial increment. Thus distance-independent indices were adequate to describe competition in young row plantations, where distance effects between trees were implicitly eliminated. Correlations between indices and height increment were not significant. Along with the increase in competition, the width and length of the crown and the diameter increment of the stem of some narrow-crowned families decreased slowly compared to wide-crowned families.

Estimates of individual heritability and genetic correlation are presented for a set of 10 growth and quality traits based on data from 16 Scots pine ( L.) progeny trials in Finland. Seven of the traits (tree height, stem diameter, crown width, Pilodyn value, branch diameter, branch angle and branch number) were objectively measured, whereas three traits (stem straightness, branching score and overall score) were assessed visually. The genetic correlations were mostly moderate or low, and favourable from the tree breeder's point of view. All variables related to tree size correlated relatively strongly and positively. Tree height exhibited a more favourable genetic relationship with the crown form traits than diameter, the latter showing positive correlation with branch diameter. Except for the slight negative correlation between branch angle and branch diameter, the branching traits were not notably correlated. The pilodyn value was positively correlated with stem diameter, reflecting negative correlation between diameter growth and wood density. The highest genetic correlations occurred among the two visually evaluated quality scores and branch diameter. All of the heritabilities were less than 0.4. Overall score, Pilodyn, branch angle, branching score and tree height showed the highest heritability.Pinus sylvestris

Dry mass and nutrient (N, P, K, Ca, Mg, B) contents of field layer vegetation and a combination of bottom layer vegetation and litter (referred to as bottom/litter layer in the text) were studied one year before and three years after fertilization (NPK and PK) on a drained low-shrub pine bog in eastern Finland. The results of an earlier study on the tree layer were combined with those of this study in order to estimate the changes caused by fertilization in the total plant biomass and litter. Before fertilization the average dry mass of the field and bottom/litter layers was 8,400 kg ha and 7,650 kg ha respectively. The above-ground parts accounted for 25% of the total field layer biomass. The dry mass of the field and bottom/litter layers together was < 20% of the dry mass accumulated in the total plant biomass and litter. The corresponding figures for N, P, K, Ca, Mg and B were 44%, 38%, 30%, 38%, 31% and 17%, respectively. Fertilization did not significantly affect the dry mass of either the field layer vegetation or the bottom/litter layer. 33% of the applied P was accumulated in the total plant biomass and litter on the PK-fertilized plots, and 25% on the NPK-fertilized plots. For the other elements, the proportions on the PK-fertilized plots were K 31%, Ca 6%, Mg 11% and B 13%. On the NPK-fertilized plots, the corresponding figures were N 62%, K 32%, Ca 6%, Mg 9% and B 13%. Except for B and K, the accumulation of fertilizer nutrients in the understorey vegetation and litter was of the same magnitude or greater than the uptake by the tree layer.-1-1

Postfire recovery of species diversity (including a number of species, entropy of species relative coverage (Shannon index of species diversity) was studied in lichen and green moss site types of Scots pine ( L.) forests in the central part of the Kola Peninsula. The results obtained indicate the difference in the dynamics of characteristics of biodiversity of forest components during postfire recovery. The stabilization of separate components of forest community varies in time from 5â15 to 120â140 years after the fire. Characteristics of the dwarf shrub and herb stratum recovered and stabilized 5â15 years after fire, while the complete stabilization of characteristics of moss-lichen cover is observed in community with fire ages of 90â140 years. Species richness of tree stratum recovered 120â140 years after fire. Time of complete stabilization of species richness of the community was estimated 120â140 years after fire. The size of the area over which characteristics of the biodiversity were estimated effected the mean values and, in most cases, the character of variation of studied characteristics. Over an area of 1 x 1 m dynamics of characteristics of species diversity coincide in forests of the studied types. Regardless of forest type within the area of 100 m species richness recovered 30 years after the fire (i.e. 3â5 times earlier than the establishment of the complete stabilization of the forest structure). That means that floristic composition of the forest remained unchanged from 30 to 210 years after the fire.Pinus sylvestris2

Part I Climate Change The productivity of Scots pine (Pinus sylvestris L.) under changing climatic conditions in the southern part of Finland was studied by scenario analysis with a gap-type forest ecosystem model. Standard simulations with the model predicted an increased rate of growth and hence increased productivity as a result of climatic warming. The gap-type model was refined by introducing an overwintering submodel describing the annual growth cycle, frost hardiness, and frost damage of the trees. Simulations with the refined gap-type model produced results conflicting with those of the standard simulations, i.e., drastically decreased productivity caused by mortality and growth-reducing damage due to premature dehardening in the changing climate. The overwintering submodel was tested with frost hardiness data from Scots pine saplings growing at their natural site 1) under natural conditions and 2) under elevated temperature conditions, both in open-top chambers. The model predicted the frost hardiness dynamics quite accurately for the natural conditions while underestimating the frost hardiness of the saplings for the elevated temperature conditions. These findings show that 1) the overwintering submodel requires further development, and 2) the possible reduction of productivity caused by frost damage in a changing climate is less drastic than predicted in the scenario analysis. The results as a whole demonstrated the need to consider the overwintering of trees in scenario analysis carried out with ecosystem models for boreal conditions. More generally, the results revealed a problem that exists in scenario analysis with ecological models: the accuracy of a model in predicting the ecosystem functioning under present climatic conditions does not guarantee the realism of the model, nor for this reason the accuracy for predicting the ecosystem functioning under changing climatic conditions. This finding calls for the continuous rigorous experimental testing of ecological models used for assessing the ecological implications of climatic change.

Part I Climate Change The effects of realistically elevated O3 and CO2 concentrations on the needle ultrastructure and photosynthesis of ca. 20 year-old Scots pine (Pinus sylvestris L.) saplings were studied during one growth period in open-top field chambers situated on a natural pine heath at Mekrijärvi, in eastern Finland. The experiment included six different treatments: chamberless control, filtered air, ambient air and elevated O3, CO2 and O3 + CO2. Significant increases in the size of chloroplast and starch grains were recorded in the current-year needles of the saplings exposed to elevated CO2. These responses were especially clear in the saplings exposed to elevated O3 + CO2 concentrations. These treatments also delayed the winter hardening process in cells. In the shoots treated with O3, CO2 and combined O3 + CO2 the Pmax was decreased on average by 50% (ambient CO2) and 40% (700 ppm CO2). Photosynthetic efficiency was decreased by 60% in all the treated shoots measured under ambient conditions and by 30% in the CO2 and O3 + CO2 treated shoots under 700 ppm. The effect of all the treatments on photosynthesis was depressive which was probably related to evident accumulation of starch in the chloroplasts of the pines treated with CO2 and combined O3 + CO2. But in O3 treated pines, which did not accumulate starch in comparison to pines subjected to ambient air conditions, some injuries may be already present in the photosynthetic machinery.

Part I Climate Change To project the changes in wood production of Norway spruce Picea abies (L.) Karst. and Scots pine Pinus sylvestris L. in Finland as a result of climate change, two separate studies were made. The first study, at the Faculty of Forestry, University of Joensuu, based its projections on mathematical models; the second one, at the Finnish Forest Research Institute, based projections on measurements of wood production in two series of aged provenance experiments. The results of the two studies were similar for both species: after a 4 °C increase of the annual mean temperature a drastic increase in wood production in northern Finland, but little effect, or even some decrease in the southern part of the country. However, the assumptions used in the two studies differed. One important difference was that in the models the temperature is assumed to be increasing gradually over the years; whereas in the provenance experiments, climate changed immediately when the seedlings were transferred to the planting sites. Another problem with the provenance experiments is that when material is moved in a north-south direction in Finland, not only temperature but also photoperiod changes markedly. To compare these two studies, site factors (e.g. soil type, temperature, precipitation) and silvicultural factors (e.g. plant spacing, survival, time of thinning, thinning intensity) from the provenance experiments were included as variables in the mathematical models.

The European Pine Sawfly (Neodiprion sertifer Geoffroy) is one of the most serious defoliators of Scots pine (Pinus sylvestris L.) in northern Europe. We studied the pattern in the regional occurrence of the outbreaks of N. sertifer in Finland in years 1961-90, and made predictions about the outbreak pattern to the year 2050 after predicted winter warming. We tested whether minimum winter temperatures and forest type and soil properties could explain the observed outbreak pattern. We analysed outbreak patterns at two different spatial levels: forest board- and municipal-level. The proportion of coniferous forests on damage-susceptible soils (dry and infertile sites) explained a significant part of the variation in outbreak frequency at small spatial scale (municipalities) but not at large spatial scale (forest boards). At the forest board level, the incidence of minimum temperatures below -36 °C (= the critical value for egg mortality) explains 33% of the variation in the outbreak pattern, and at the municipal level the incidence of cold winters was also the most significant explaining variable in northern Finland. Egg mortality due to cold winters seems to be the most parsimonious factor explaining why there have been so few N. sertifer outbreaks in northern and north-eastern Finland. We predict that climate change (increased winter temperatures) may increase the frequency of outbreaks in eastern and northern Finland in the future.

Part I Climate Change Investigations carried out in the Kola peninsula (northern taiga) and in the South-western part of Western Siberia (southern taiga and forest-steppe) revealed identical course of the postfire restoration process of forest litter thickness in Scots pine forests. Despite the differences in mean annual temperature (2 °C) and other climatic characteristics the recovery time for thickness of forest litter in both regions amounts to 90–100 years after fire in pine forests of lichen site type and 120–140 years – in green moss type; the thickness of forest litter therewith corresponds 3–4 cm and 7–8 cm respectively. That means that within the natural borders of pine forests, communities of a specific type possess uniform characteristics of restoration. On the basis of empirical data it appears that the predicted increase of mean annual temperature of earth surface by (2 °C) will not bring changes into the character of postfire recovery of forest litter thickness. It was shown that during the period of the recovery, which spans about 90 years after fire in pine forests of lichen and green moss–lichen site types and 140 years in ones of green moss site types, the rate of increasing of carbon store in the forest litter averaged 0.6 t ha–1 year–1, 0.1 t ha–1 year–1 and 0.2 t ha–1 year–1, respectively.

The prescribed burning of a 7.3 ha clear-cut and a 1.7 ha partially cut forest (volume 150 m3/ha) was carried out in Evo (61°12'N, 25°07'E) on 1 June 1992. The forest was a mesic Myrtillus site type forest dominated by Norway spruce (Picea abies (L.) Karst.). Practically all the trees and the above-ground parts of the understorey vegetation died in the fire, while the mor layer was thinned by an average of 1.5 cm. A study was made on the change of germinated seedling populations in time and their dependence on environmental factors. Seedlings of Norway spruce, Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), pubescent birch (B. pubescens Ehrh.) and rowan (Sorbus aucuparia L.) were inventoried in 1993 and in 1994 on permanent plots, four times per growing season. Autoregression models were used to compare regeneration of tree species in the burned forest with regeneration in the burnt clear-cut area, and to study the effect of distance from nearest seed source to regeneration. The average number of seedlings germinating in 1993 was higher than in 1994, probably because of differences between these consecutive years in regard to the amount of seed rain and weather conditions. The number of Norway spruce and rowan seedlings was higher inside the forest area than in the clear-cut area. The distance to the bordering forest and to the closest seed trees did not explain the result. It is suggested that the more stable microclimatic conditions under the shade of dead trees promote germination and seedling establishment in the forest area. As rowan is a bird-dispersed species, it is likely that dead trees help the dispersal of rowan seeds by providing birds places to sit and defecate. The shade provided by dead trees may influence the further succession of the tree stand and vegetation composition and diversity.

Germination of Norway spruce ( (L.) H. Karst.) and Scots pine ( L.) pollen decreased during exposure to open air conditions. Usually more than half of the pollen remained germinative after a few days outdoors, but following more than four days outdoors the germination became very low. This study supports the opinion that pollen in the atmosphere remains viable long enough to allow for long-distance gene flow by pollen migration, as an important factor in genetic management of conifers and in evolution, maintaining diversity and potential for adaptation.Picea abiesPinus sylvestris

Seasonal fluctuations in free polyamines, spermidine, spermine, putrescine and potassium concentrations were studied for two years (1992–1993) in three needle years of Scots pine (Pinus sylvestris L.) grown on a drained mire in western Finland. Seven different fertilizer treatments involving five different sources of potassium were used. Putrescine concentrations were high in winter and in May but low in summer. High peaks in putrescine in March and May could be found in non-refertilized or rock phosphate treatments. Spermidine and spermine concentrations were high in March and May. In December spermine concentrations were low. Biotite increased the needle potassium concentrations less than the other potassium fertilizers but the putrescine concentrations or the putrescine/spermidine ratio to about the same level. This suggests that biotite, although very slowly soluble, can reasonably satisfy potassium nutrition of young pine trees. The potassium concentrations of needles in all the fertilization treatments were higher in winter than in summer. The response of putrescine to the potassium concentration was strongly negative in all the needle years and sampling times. In March, May and December the response of putrescine to potassium was fairly similar in both years but not in June and August. The results suggest that the potassium concentrations during the growing season cannot be used for estimating the potassium nutrition of trees, because the variation between the years may be substantial, whereas the needle putrescine concentration or putrescine/spermidine ratio indicates the suboptimum potassium status of Scots pine fairly well. Needle putrescine concentrations over 500 nmol g–1FW quite regularly coincided with a nonsatisfactory potassium nutrition and concentrations over 1000 nmol g–1FW were a reliable indication of potassium deficiency. Putrescine/spermidine ratios below 5 indicated a satisfactory potassium nutrition in all needle years throughout the year.

Concentration of the phytotoxic air pollutant, ozone (O) is continually increasing in the lower layer of the troposphere. The purpose of this study was to compare performance of pine sawflies on Scots pine ( L.) seedlings in ambient and future levels of ozone. Scots pine seedlings were grown in field fumigation system where the ozone doses in fumigated plots were 1.5â1.6 times the ambient level. Larvae of the European pine sawfly ( Geoffroy and Klug) were reared on the foliage of Scots pine. The levels of resin acids and monoterpenes in foliage were analysed. There were no significant effects of ozone fumigation on sawfly performance or levels of defence compounds in pine foliage. The results suggest that the elevated ozone concentrations do not strongly affect the needle quality of young Scots pine and the importance of these two diprionid sawfly species forest pests.3Pinus sylvestrisNeodiprion sertiferGilpinia pallida

The eddy covariance technique is a novel micrometeorological method that enables the determination of the atmosphere-biosphere exchange rate of gases such as ozone and carbon dioxide on an ecosystem scale. This paper describes the technique and presents results from the first direct measurements of turbulent fluxes of O3, CO2 and H2O above a forest in Finland. The measurements were performed during 15 July-5 August 1994 above a Scots pine (Pinus sylvestris L.) stand near the Mekrijärvi research station in Eastern Finland. The expected diurnal cycles were observed in the atmospheric fluxes of O3, CO2 and H2O. The data analysis includes interpretation of the O3 flux in terms of the dry deposition velocity and evaluation the dependency of the net CO2 flux on radiation. The eddy covariance method and the established measurement system has proved suitable for providing high-resolution data for studying ozone deposition to a forest as well as the net carbon balance and related physiological processes of an ecosystem.

A one hectare plot in a Scots pine (Pinus sylvestris) forest was systematically sampled for surface soil characteristics: humus layer thickness, soil carbon and nitrogen content, pH, electrical conductivity and respiration were determined from 106 samples. The effects of large trees on the plot were mapped and their joint influences at the locations of soil sampling were described as the influence potential, derived from the ecological field theory, and were calculated based on the locations and dimensions of trees. The range of variation of soil characteristics was from three to sevenfold; no spatial autocorrelation was detected. The calculated influence potential of trees, as determined by their size and spatial distribution, was related to the spatial variation of top soil properties. Top soil properties were also related to thickness of the humus layer but they were poorly correlated with underlying mineral soil characteristics. Humus layer thickness, with the calculated influence potential of trees, may provide a means to predict top soil characteristics in specific microenvironments in the forest floor.

Fill planting is a common procedure following reforestation in Finland. In 1990, 13% of the total of seedlings planted was used for fill planting. The objective of this study is (i) to survey the survival of fill-in seedlings and (ii) to estimate the spatial pattern of stands to evaluate the importance of fill-in seedlings in constituting the stocking of Scots pine stands in central and northern Finland. A survey of 63 artificially regenerated Scots pine stands was conducted in 1990. Stand densities varied from 950 to 3925 seedlings/ha. The mean densities of originally planted, fill planted, and naturally regenerated seedlings were 863, 639, and 791/ha, respectively. The survival of originally planted seedlings was 36% and that of fill-in seedlings 48%. Death rate of fill-in seedlings of Scots pine increased with longer times between original and fill planting, with higher survival rates of original seedlings, and with increased time since fill planting. The survival rate of Norway spruce seedlings was correlated with temperature sum. Height of the fill-in seedlings was less than that of the originally planted seedlings. Most stands had an even spatial distribution with the exception of sparsely populated stands, which were somewhat clustered. This indicates that dying of seedlings is not randomly spread. Because of poor survival, fill planting seems to be a risky business in most cases.

Tree height data from 33 progeny trials of Scots pine (Pinus sylvestris L.) were used to determine the effect of within-plot subsampling on the magnitude of statistically detectable differences between families, family heritability and correlation of family means based on different sample sizes. The results indicated that, in trials established with a standard plot configuration of 25 trees per plot, measuring only 10–15 trees gives nearly the same precision as with assessment of all the plot trees. Even as few as 4–6 trees assessed per plot may constitute a sufficient sample if families or parental trees of extreme performance are being selected. Trials established with non-contiguous plots were found to be more efficient than those established using multiple-tree contiguous plots.