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Many forest-dwelling species are dependent on deadwood. Sources of deadwood include competition- and senescence-related mortality of trees, and various damages. This study described a methodology for predicting the effect of wind damage on the amount of deadwood and suitability of the forest for saproxylic species. The methodology was used in a forested boreal landscape of 360 ha to analyze the effects of wind damage on the habitat quality for 27 groups of saproxylic species differing in their requirements for the species, size and decay stage of deadwood objects. A reference plan maximized net present value (MaxNPV) while others either minimized or maximized height differences between adjacent stands. Maximization of height differences resulted in high amount of wind damage and deadwood while minimizing height differences minimized wind damage and the amount of damage-related deadwood. The fourth plan maximized the average habitat suitability index (HSI) of the 27 groups of saproxylic species. The plans were compiled with and without even-flow harvesting constraints for three 10-year periods. Maximization of height differences between adjacent stands resulted in higher HSI values than obtained in the MaxNPV plan or in the plan than minimized height differences between adjacent stands. The average HSI of shade-demanding species correlated negatively with the amount of harvested timber. No strong correlations were found for light-demanding and indifferent species.

We employed simulations by forest ecosystem (SIMA) and mechanistic wind damage (HWIND) models in upland boreal forests throughout Finland to study regional risks of wind damage under changing management preferences and climates (current, RCP4.5 and RCP8.5 scenarios) over 2010–2099. We used a critical wind speed for the uprooting of trees as a measure of vulnerability, which together with the probability of such wind speed defined a level of risk. Based on that, we also predicted the stem volume of growing stock at risk and the amount of damage. In this work, medium fertility sites were planted to one of Scots pine, Norway spruce or silver birch, or to the tree species that was dominant before the final clear-felling. The vulnerability to wind damage, the volume of growing stock at risk and the amount of damage all increased and the most in the south, when the proportion of Norway spruce (with shallow rooting) of the growing stock increased. Under a severe climate warming, the proportion of Norway spruce decreased the most in the south, opposite to that of birch. This decreased the risk of damage in autumn (while birch is leafless), unlike in summer. The low risk of damage in the north was due to the large proportion of Scots pine., final draft, peerReviewed

This study presents a new method for considering the risk of wind damage in forest planning and for predicting the amount of damage and its effects on timber production, economic profitability and carbon balance of forestry. The effects of wind damage on the optimal management of boreal forests under current and changing climatic conditions were analyzed by comparing four forest management plans. A reference plan maximized net present value (NPV) with even-flow harvesting constraints. The second plan minimized height differences between adjacent stands, the third minimized height differences while simultaneously maximizing NPV, and the fourth maximized height differences between adjacent stands. To obtain damage-adjusted results, schedules that belonged to the optimal management plans were simulated with wind damage, taking into account the shelter provided by adjacent stands. Maximizing NPV and simultaneously minimizing height differences resulted in the highest damage-adjusted NPV. Increasing wind damage increased carbon balance of forest soil but decreased the total carbon balance of forestry as it decreased the carbon balances of living forest biomass and wood-based products. Climate change slightly improved the total carbon balance of forestry. If wind damage was ignored in calculations, NPV, total carbon balance of forestry, and timber production were overestimated.

We studied the effects of different wood harvesting and utilisation policies on the carbon balance and economic profitability of forestry under the current and changing climate (A1B climate scenario). Sixty-year carbon balance was calculated for two Finnish boreal case study areas, one dominated by Scots pine and the other by Norway spruce. Carbon balance included changes in the carbon pools of living forest biomass (above- and below-ground), dead organic matter and wood products, as well as carbon releases from harvesting, transporting and manufacturing. Substitution effects of using biofuel instead of fossil-fuels were also taken into account. Business-as-usual (baseline) management policy (even-aged forestry: thinning from below, harvesting timber for wood-based products from thinning and final felling) and five other management policies were applied by changing the timing and type of thinning and the utilisation of harvested trees. Net present value (NPV, 2%) and carbon balance were maximised with even-flow net income constraints. In both case study areas, postponing the thinning of young stands and using thinning from above improved carbon balance and NPV. The use of pulpwood, logging residues and stumps as biofuel also increased carbon balance. Climate warming improved carbon balance and NPV when harvests were not increased from those under the current climate.

In this work, we employed two different ecosystem models in two separate case studies to assess the effects of forest age structure, management and gradual climate change on timber production and carbon sequestration of Finnish boreal forests with Norway spruce as main (dominant) tree species. Our case study examples demonstrated that over the 90 years simulation period the total timber production was from 16 to 30 % lower in southern Finland under the mild (SRES B1) and strong (SRES A2) climate change scenarios . In the northern Finland, the total timber production increased regardless of climate change scenario applied. Furthermore, both total timber production, its economic profitability and carbon stocks of forest ecosystem could be increased simultaneously if higher stocking (growing stock volume) was maintained over the rotation compared to the Finnish baseline forest management. However, timber production and carbon sequestration could not be maximised simultaneously. Thus, any preference of carbon sequestration in forest management would reduce the timber production and would result on opportunity costs.

The relationships between anatomical characteristics of wood, growth, and wood density were studied in three Finnish Norway spruce ( Picea abies (L.) Karst.) clones, which had differences in average stem volume and wood density. This was done to determine which anatomical characteristics are affected by growth and which affect wood density and to determine if clones of different geographical origins (Southeastern, C43; Southern, C308; Southwestern, C332) differ from each other in these respects. In this study, tracheid double wall thickness, lumen diameter, and wall to lumen ratio, numbers, sizes, and percentages of resin canals, and numbers of rays were correlated with ring, earlywood, and latewood widths and densities. The wood density correlated positively with the wall to lumen diameter ratio. Rapid growth decreased the number of rays independently of the clone. Furthermore, the effects of growth on the number and size of resin canals depended strongly on the clone. C332 had very thin tracheid walls in latewood, which decreased wood density. However, the high number of rays and resin canals increased it. Growth significantly influences wood anatomy and, consequently, wood density. Hence, wood anatomy should be considered in the selection of proper genotypes for forest cultivation in a changing growing environment., final draft, peerReviewed

In boreal conditions, climate change is expected to increase mean annual temperature and precipitation, increasing forest growth and productivity in managed forests. In this study, we aimed at finding out how climate change affects the optimal management of Scots pine-, Norway spruce- and silver birch-dominated stands on sites of varying fertility (high-herb, mesic and sub-xeric sites) in the boreal forests of central Finland. The objective function was to maximise net present value (NPV), considering the future incomes from timber sales and costs of forest operations. The results showed that under the gradually changing climate, the optimised management schedules differed from those observed under the current climate. In Norway spruce- and birch-dominated stands, cuttings were done earlier under the changing climate than under the current climate, while in Scots pine-dominated stands they were delayed under the changing climate. The optimised management schedules also varied, depending on tree species and site fertility types. Under the changing climate, both timber production and NPV increased compared to the current climate, regardless of species and site fertility type.

Modeling forest trees’ mensurational relationships has many applications: from understanding physiological functional relationships (e.g. the allometric relationship of sapwood to leaf area ratio) to predicting one tree part by measuring another (e.g. above-ground tree biomass from the tree stem diameter). Simple models that relate easy to measure tree characteristics, such as diameter at breast height (DBH), to other more difficult to observe dimensions such as crown volume, are useful both in and of themselves and also as components of larger forest growth and yield and forest ecosystem models. Mensurational models of wide applicability include tree height-DBH (growth and yield models, carbon accounting, forest dynamics), bark thickness-DBH (fuels and fire models, carbon accounting, post-fire mortality), and crown dimensions-DBH (physiological models, growth and yield models, carbon accounting models). Here we develop models for plantation-grown loblolly pine ( Pinus taeda L.) trees in Uruguay. We model total tree height-DBH, crown diameter-DBH, crown volume-DBH, and bark thickness stem profile given relative diameter and relative height. We do so using linear and nonlinear regression models as well as semi-parametric modeling alternatives. The data comprise 198 trees grown in even-aged plantations and spanning an age range of 8–22 years. The predictive ability of the resulting models was evaluated by estimating the root mean square prediction error by predictor variable classes with the 0.063+ bootstrap method. All models presented acceptable prediction ability except the one describing the relationship of crown volume to DBH. The semi-parametric model describing the bark thickness profile along the tree stem fit the data better and had similar prediction ability compared with the parametric model. The semi-parametric modeling approach was a good alternative to describe this allometry.

The aim of this study was to analyse the effects of cambial age, clone and climatic factors (i.e. monthly mean temperature and monthly total precipitation) on ring width (RW) and ring density (RD) development from pith to bark in 30-years-old Norway spruce (Picea abies) grown on a fertile agricultural soil in southeastern Finland. The material consisted of 20 Finnish clones, which represented south, southwest, southeast and central Finnish origins. We analysed the variability of RW and RD among years, individual trees and clones, by fitting mixed models into tree ring series, with a spline function (used to remove the effect of ring age). The results showed that cambial age, clone and mean temperature of July affected both RW and RD. Furthermore, total precipitation of August affected RW and total precipitation of May affected RD. However, these climate variables explained only 1.9% and 3.4% of the total RW and RD variability, respectively. This may be due to the good site fertility with no lack of soil water availability, but also due to relatively short tree ring series available for data analyses. The effect of mean temperature of July on RW varied among clones, but in general, RW increased with increase in temperature. The increase of total precipitation of August increased, in general, RD regardless of the clone, whereas the effect of mean July temperature on RD was much more variable. However, longer time series are needed in the future to provide a better understanding of the interactive effects of the climate variables and genetic origins, in addition to cambial age, on RW and RD development on different sites.

The effects of genetic entry and competition on the above ground dry biomass production (i.e. stem wood, needles, branches and harvest index) was studied in 20 Norway spruce ( Picea abies (L.) Karst.) clones grown in southern Finland. Furthermore, the measured above ground biomass components were compared against the corresponding estimations based on biomass models developed previously. The clones included both Finnish and Russian clones, as well as provenance-hybrids clones. Differences existed between clones in stem dry mass production, but not in harvest index or in crown dry mass. However, the competition caused by neighboring trees also significantly affected above ground dry biomass, as well as the biomass of crown and stem separately. Differences in competition between the clones could not be found. Unlike the dry mass of branches, the dry mass of needles and stem could be estimated well for individual sample trees with the available biomass models. Moreover, the clone with the largest above ground dry biomass production had nearly doubled production, on average, than the average over all clones. Thus, some of the clones showed especially high potential for biomass recovery in energy wood thinning.

We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment. The climate scenario included a doubling of [CO(2)] and a corresponding increase of 2-6 degrees C in temperature at the site depending on the season. Anatomical characteristics analyzed were annual earlywood, latewood and ring widths, intra-ring wood densities (earlywood, latewood and mean wood density), tracheid width, length, wall thickness, lumen diameter, wall thickness:lumen diameter ratio and mass per unit length (coarseness), and numbers of rays, resin canals and tracheids per xylem cross-sectional area. Elevated [CO(2)] increased ring width in four of six treatment years; earlywood width increased in the first two years and latewood width in the third year. Tracheid walls in both the earlywood and latewood tended to become thicker over the 6-year treatment period when temperature or [CO(2)] was elevated alone, whereas in the combined treatment they tended to become thinner relative to the tracheids of trees grown under ambient conditions. Latewood tracheid lumen diameters were larger in all the treatments relative to ambient conditions over the 6-year period, whereas lumen diameters in earlywood increased only in response to elevated [CO(2)] and were 3-6% smaller in the treatments with elevated temperature than in ambient conditions. Tracheid width, length and coarseness were greater in trees grown in elevated than in ambient temperature. The number of resin canals per mm(2) decreased in the elevated [CO(2)] treatment and increased in the elevated temperature treatments relative to ambient conditions. The treatments decreased the number of rays and tracheids per mm(2) of cross-sectional area, the greatest decrease occurring in the elevated [CO(2)] treatment. It seemed that xylem anatomy was affected more by elevated temperature than by elevated [CO(2)] and that the effects of temperature were confined to the earlywood.

A process-based model was used to assess the sensitivity of timber production and carbon (C) sequestration to the structure (in terms of age class distribution) of a boreal forest landscape and to the management under changing climatic conditions. Moreover, an approach to calculate the cost of C sequestration, through C sink enhancement, was used by computing the potential loss in the net present value (NPV) of timber when management with maximum C stock is chosen. Regardless of the climate scenario and initial age class distribution used, management had a clear effect on the mean C stock in the forest ecosystem. Any management regime allowing a higher tree stocking than business-as-usual management increased the timber production and simultaneously maintained or increased the C stock in the forest ecosystem. On the other hand, the maximum C stock in the forest and the lowest NPV were observed when no thinning was applied before the final cut. The changing climate increased forest productivity and also C stock. When using the same management for the entire management unit, the initial age class distribution had a large influence on the results of timber production (up to 20% difference) but not on C stock in the forest ecosystem (3%).

Research Article Assessment of forest fuel loading is a prerequisite for most fire management activities. However, the inclusion of shrub biomass in forest planning has been hindered by the inability to predict its growth and accumulation. The main objective of this study was to model shrub biomass over time under a tree canopy with the aim of including shrub management in fire risk mitigation plans. To this purpose, data was obtained from the 4th and 5th Portuguese National Forest Inventories. Five biologically realistic models were built to describe shrub biomass accumulation in Portuguese forests. The selected model indicates that maximum biomass is affected by stand basal area and the percentage of resprouting shrub species in the stand. Biomass growth rate was clearly affected by the regeneration strategies of shrubs in combination with climatic conditions (mean annual temperature). The model can be used in the accumulation form for initialization purposes or in one of the two alternative difference forms to project observed shrub biomass. The model proposed in this study facilitates the inclusion of shrub biomass in forest growth simulations, and will contribute to more accurate estimates of fire behavior characteristics and stored carbon. This is essential to improve decision-making in forest management plans that integrate fire risk, namely to schedule understory fuel treatments info:eu-repo/semantics/publishedVersion

In this work, we assessed the factors affecting wind and snow damage of individual trees in a small management unit in western Finland. This was done based on inventoried damage and observed wind speeds and snow loading in storms Pyry and Janika in 2001 and Mielikki in 2002 together with mechanistic model. First, we studied which factors explain the observed damage in individual trees. Secondly, we studied how well the mechanistic model (HWIND) could predict the wind speed needed to uproot individual trees at the margins of permanent upwind edges. We found that Pyry storm caused 70% and Janika and Mielikki 18 and 12% of observed damage. In Janika storm, all trees uprooted. In other storms, both uprooting and stem breakage occurred. Scots pine suffered the most damage. Recently thinned stands on the upwind edges of open areas suffered the most damage. But, damage occurred also on soils with relatively shallow anchorage. HWIND predicted correctly damage for 69% of all uprooted trees. No-uprooting was correctly predicted for 45 and 19% of standing trees (all Scots pines), which were measured within and at the immediate upwind edge of same stands. HWIND model needs further validation at the permanent edges and/or on soils with shallow rooting to improve its prediction accuracy in such conditions.

• Introduction The objective of this work was to study how spacing and genetic entry and/or origin group affect radial growth (ring width and cumulative diameter development) and ring density from pith to bark in Scots pine (Pinus sylvestris L.) and in what sense their annual variability could be explained by the climatic variables. The spacing trial was located in central Finland, with current stand density range of 2,000–4,000 trees per hectare. All the six genetic entries had Kanerva pine (plus tree S1101) as a father tree, whereas the mother tree represented Finnish plus trees from southern, central and northern Finland.

International audience; We studied the differences in branch characteristics along the stems of six different genetic entries of 20 year old Scots pines (Pinus sylvestris L.) grown at different spacing (current stand density range 2000-4000 trees ha−1) in central Finland. Furthermore, we studied the phenotypic correlations between yield, wood density traits and branch characteristics. All the genetic entries had Kanerva pine (plus tree S1101) as a father tree, whereas the mother tree represented Finnish plus trees from southern, central and northern Finland.* Spacing affected all yield traits, wood density and living branch characteristics such as relative average branch diameter and relative cumulative branch area (p < 0.05). As a comparison, genetic entry affected height, while origin group (southern, central and northern ones) affected most of the studied traits. Regardless of spacing, the northern origin had, on average, the largest stem diameter and highest wood density, while the central one was the tallest one. Furthermore, average branch diameter along the stem was affected by branch age, origin group and spacing, while average branch angle was affected by branch age and genetic entry (p < 0.05).* In general the average branch size could be decreased especially in lower tree canopy by denser spacing during the early phase of the rotation, but only at the expense of tree growth. Correspondingly differences between origins are mainly related to their differences in stem growth.

In forest breeding, stem volume growth and sawn timber quality indicators have been used as the most important selection traits for Scots pine, whereas less attention has been given to characteristics such as fibre properties. In the above context, we investigated the differences in fibre properties (i.e. fibre length, fibre width and coarseness) in 20 year old Scots pine (Pinus sylvestris L.) genetic entries as affected by spacing and site, but also the phenotypic correlations between fibre properties, yield and wood density. The study was based on materials harvested from 10 genetic entries grown in a spacing trial (site 1) in central Finland, with a current stand density of 2000 (spacing 1), 2000–2500 (spacing 2) and 4000 trees/ha (spacing 3). In order to study the effects of site, we harvested additional material (4 of 7 genetic entries same as on site 1) from a trial located in southern Finland with a corresponding stand density of 2000 trees/ha (site 2). On site 1, spacing 1 and 3, all average values for analysed fibre properties were similar. In spacing 2 average values were slightly higher. On site 2, the average values for different fibre properties were similar compared to the corresponding spacing 1 on site 1. Spacing affected (p < 0.05) all average fibre properties on site 1; as did also site, when comparing same genetic entries grown on both sites. Regardless of spacing and site, the phenotypic correlations between average fibre length, fibre width and coarseness showed, on average, moderate to strong correlation (p < 0.05). Fibre width showed, in general, low and positive phenotypic correlation with diameter at breast height, stem volume and wood density on site 1. However, as a whole, the ranking of genetic entries changed depending on the trait and spacing considered. Thus, no overall ranking between genetic entries was possible.

In forest breeding, stem volume has typically taken as the most important selection trait, whereas less attention has been given to wood density traits. In this work, we investigated the effects of spacing and genetic entry on the growth, yield and wood density traits in 20 year old Scots pines (Pinus sylvestris L.) based on 10 genetic entries harvested from a spacing trial (stand density range 2000–4000 trees/ha) in central Finland. In order to study also the site effects, we harvested additional material from a trial located in southern Finland (stand density of 2000 trees/ha). Compared to growth and yield properties, wood density traits showed a lower phenotypic variation. Phenotypic correlations among different traits were negative, and mostly moderate to high, suggesting that selection for one trait would simultaneously affect the others. In addition, moderate to strong phenotypic correlations were found among different wood density traits. Stem volume (V) and breast height diameter (DBH) were the largest in widest spacing, whereas in the densest one tree height (H) and latewood percentage were the highest. Genetic entry affected H and wood density traits regardless of spacing. When comparing two sites (with same stand density), genetic entry affected H, whereas site affected DBH and wood density traits. Ranking between genetic entries changed depending on the trait, spacing or site considered. Therefore, no overall ranking was possible. However, we could identify genetic entries having a high V and a relatively high wood density, showing potential for future forest regeneration material.

We investigated the growth, yield, wood density traits and fibre properties in 13 narrow crowned Norway spruce (Picea abies f. pendula) clones grown at a spacing of 2 m x 1.5 m (about 3300 seedlings/ha) in a field trial established in 1988 in southern Finland on a forest soil. For comparison, we used 3 normal crowned Norway spruce (Picea abies (L.) Karst.) genetic entries grown as a mixture in the same trial representing southern Finnish breeding regions. We found that wood density traits and fibre properties showed, on average, lower phenotypic variation than growth and yield traits regardless of crown type. Narrow crowned clones also had, on average, lower stem volume and fibre length, but higher overall wood density. More over, the phenotypic correlations between studied growth and wood properties ranged, on average, from moderate (normal crown) to high (narrow crown). These results were opposite to previous findings for narrow and normal crowned genetic entries grown in narrower spacing (1 m x 1 m) in southern Finland. Thus, this indicates lower plasticity of narrow crowned clones to the increasing growing space compared to normal crowned ones, so, they should be grown at denser spacing in order to fully utilise its space efficiency capacity. However, this field trial was established as a mixture of normal and narrow crown trees, so that 90% of genetic entries were narrow crowned ones, and therefore the crown competition would be much higher for normal crowned trees when the whole trial would consist of that entry alone. In the latter case, we could expect significantly lower productivity of normal crowned genetic entries with this spacing.

In recent years there has been increased interest in the so called narrow crowned Norway spruce (Picea abies f. pendula), which is a rare mutant of Norway spruce (Picea abies (L.) Karsten), as a suitable wood raw material source for pulp and paper production. This is because it is less sensitive to competition than the normal crowned Norway spruce, and thus, could be more productive especially at dense spacing. In the above context, we investigated how the growth and yield (such as height, diameter, stem volume and ring width) in addition to wood density traits and fibre properties (such as wood density, fibre length and width, cell wall thickness and fibre coarseness) were affected in trees from 9 full-sib families representing narrow crowned Norway spruce grown at narrow spacing of 1 m 1 m in Southern Finland. For comparison, we used normal crowned Norway spruce trees from 6 breeding regions. We found that, compared to growth and yield traits, wood density traits and fibre properties showed, on average, lower phenotypic variations. In addition, these variations were smaller for narrow crowned families than for normal crowned genetic entries. Narrow crowned families also showed, on average, higher growth and yield and fibre length, but lower wood density. Moreover, the phenotypic correlations between growth, yield, wood density traits and fibre properties, ranged, on average, from moderate (narrow crowned) to high (normal crowned). As a whole, the growth and wood properties of narrow crowned families were found to be less sensitive to tree competition than the normal crowned genetic entries used as a comparison.

International audience; The aim of this work was to study both the effects of genetic entry and competition by neighbouring trees on growth, yield, wood density traits and fibre properties of 20 Norway spruce clones grown in an experimental trial located in southern Finland. The material included 10 Finnish clones, 2 Russian clones and 8 provenance-hybrids clones, the latter ones representing crosses between Finnish and foreign parent trees.* We found that, compared to growth and yield, wood density traits and fibre properties showed, on average, lower phenotypic variations. Moreover, significant differences could be observed among the clones regardless of the trait (p < 0.05). Conversely, on average, no clear differences could be found between Finnish, Russian and provenance-hybrids clones in most of the studied traits.* The marked differences among the clones, and lack of clear differences among the provenances suggested that any ranking, regarding different traits, should be based on individual clones. The phenotypic correlations between different traits ranged from moderate to strong suggesting that selection based on one trait would affect other traits. Regardless of clone, the growth of trees (e.g. breast height diameter) decreased and the wood density increased with increasing competition by neighbouring trees, which was expressed by competition index.; Le but de ce travail était d'étudier à la fois les effets de la part génétique et de la concurrence des arbres voisins sur la croissance des arbres, la production, les caractéristiques de la densité du bois et les propriétés des fibres de 20 clones d'épicéa cultivés dans un dispositif expérimental d'essai situé dans le sud de la Finlande. Le matériel était constitué de 10 clones finlandais, 2 clones de Russie et de 8 provenances de clones hybrides, ces derniers représentant les croisements entre arbres parents le Finlandais et étrangers.* Nous avons trouvé que, comparativement à la croissance et à la production, la densité du bois et les caractéristiques des propriétés des fibres montraient, en moyenne, de plus faibles variations phénotypiques. En outre, des différences significatives ont pu être observées chez les clones, quel que soit le caractère (p < 0,05). Inversement, en moyenne, pour la plupart des caractéristiques étudiées, on n'a pas constaté de différences claires entre les clones finlandais, russes et les provenances de clones hybrides.* Les différences marquées entre les clones, et l'absence de différences évidentes entre les provenances ont suggéré que tout classement, en ce qui concerne les différentes caractéristiques, devrait être basé sur des clones individuels. Les corrélations phénotypiques entre les différentes caractéristiques varient de modéré à fort, suggérant que la sélection sur la base d'une caractéristique serait de nature à affecter les autres caractéristiques. Indépendamment des clones, la croissance des arbres (par exemple le diamètre à hauteur de poitrine) a diminué et la densité du bois a augmenté avec l'accroissement de la concurrence des arbres voisins, qui a été exprimée par l'index de concurrence.