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Based on model simulations, we studied the sensitivity of the production of energy biomass and timber to varying precommercial
stand densities. Additionally, we studied their sensitivity to varying thinning regimes alone or combined
with nitrogen fertilization. The net present value (NPV) was used to identify the cost-efficiency of management regim...
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... for Norway spruce and for Scots pine), the timing varies depending on stand density after pre-commercial thinning. However, if the stand density is relatively high in young stands (e.g. due to additional natural regeneration especially by broadleaves, seeding of Scots pine and/or if tending of seedling stand has been delayed or not done), energy wood thinning would also be an option at a dominant height of 8–14 m. If the energy wood thinning is done as whole tree harvesting, the loss of nutrients, as a result of needle loss, may lead to a subsequent decrease in the growth of the re- maining trees (Kuusinen and Ilvesniemi, 2008). Therefore, it could be recommended only for stands with adequate site fertility, especially if nitrogen fertilization is not used to compensate for this nutrient loss (Anonymous, 2006). It is recommended that compensation fertilization is under- taken when the crown biomass is extracted more than once during a rotation (Skogsstyrelssen, 2001). In boreal conditions, such as in Finland, the potential for biomass production would be higher than that produced based on current traditional management recommenda- tions solely aiming for timber production for the wood processing industry. In boreal conditions, forest growth is mainly limited by relatively low summer temperatures, short growing season and limited availability of nitrogen (Linder, 1987; Kellomäki et al. , 1997). Thus, nitrogen fer- tilization in young stands could increase the amount of fo- liage (and leaf area) produced (Linder and Axelsson 1982; Vose and Allen 1988; Albaugh et al. , 1998), also resulting in a larger amount of absorbed energy used in stem wood production compared with unfertilized stands (Linder and Axelsson, 1982; Linder, 1987). Fertilization has played an important role in the wood production programmes in the 1960s and 1970s in Finland, significantly increasing the growth of upland forests (Kukkola and Nöjd, 2000). However, in practice, the growth response depends, to a certain extent, on the growth preceding fertilization (Viro, 1967; Gustavsen and Lipas, 1975). Good results have been achieved especially on sites where growth has also been relatively good before nitrogen (N) fertilization. In such conditions, N fertiliza- tion of 150 kg ha − 1 might be expected to increase growth by 12–20 m 3 ha − 1 over a rotation (Kaunisto et al. , 2002). This could also positively affect both timber and energy wood production potential. When aiming at concurrently producing timber and en- ergy wood in a cost-efficient and environmentally friendly manner, additional issues such as logging costs should be considered, which are high for small-dimensioned trees (e.g. their handling limits the capacity of the logging ma- chines and tends to decrease the productivity of work). The profitability of energy wood thinning is also dependent on the energy wood price as well as subsidies (Laitila, 2008). Forest growth models (as ecosystem models like SIMA and statistical growth and yield models like MOTTI) are essential tools in forest management because they can be used to analyse of the sensitivity of modelled stem wood production to different silvicultural treatments (e.g. spa- cing, thinning, fertilization) and varying environmental conditions (e.g. Kellomäki et al. , 1992; Hynynen et al. , 2005). Such models could also be used to support the de- cision making for optimal management solutions in prac- tical forest planning (Hynynen et al. , 2005; Hyytiäinen et al. , 2006; Pretzch et al. , 2008). This would not be possible purely based on empirical approaches. In this study, the main aim was to investigate how to in- crease the production of energy biomass when producing stem wood for industrial purposes. In this context, the sen- sitivity of stem wood production (energy wood, pulp and saw logs) to the varying pre-commercial stand density and following commercial thinnings (timing and intensity) and nitrogen (N) fertilization (number and amount) treat- ments was studied based on model simulations. They concern Norway spruce and Scots pine stands grown on sites with varying site fertility by applying a fixed rotation period of 80 years. In addition to stem wood produc- tion, we also considered the effects of management on net present value (NPV, € ha − 1 ) to identify the cost-efficiency of management regimes. This work was undertaken using the ecosystem model SIMA (Kellomäki et al. , 1992; Kolström, 1998), which is a gap-type model utilizing a time step of 1 year. In the model, the growth of a tree is based on diameter growth, which is the product of the potential diameter growth and environ- mental factors. The model incorporates four subroutines describing the site conditions (environmental subroutines) in terms of temperature sum (degree days, d.d.), within- stand light conditions, soil moisture and soil nitrogen. In addition, a procedure for management, including thinning and fertilization, is incorporated in the model (Figure 1). The environmental subroutines are linked by the multi- pliers to the demographic subroutines (birth, growth and death); i.e. G = G o ·M 1 . . . M n , where G is growth and/ or regeneration, G o growth and/or regeneration in optimal conditions and M 1 . . . M n multipliers for different envir- onmental factors. The subroutine converts the temperature sum, as well as light availability, soil water and nitrogen into growth multipliers. The death of the trees is deter- mined by the crowding with the consequent reduction in growth, which determines the risk for a tree to die at a given moment. Litter and dead trees end up on the soil to be decomposed, with the release of nitrogen in the long run. The simulation of the above processes and the conse- quent succession that takes place in the forest ecosystem is based on the Monte Carlo simulation technique; i.e. cer- tain events, such as birth and death of trees, are stochastic events. Consequently, each time such an event is possible (e.g. it is possible for a tree to die every year), the algo- rithm selects whether or not the event will take place by comparing a random number with the probability of the occurrence of the event. The probability of an event is a function of the state of the forest ecosystem at the time when it is possible. Each run of a Monte Carlo code is one realization of all possible time courses of the forest ecosystem. Therefore, the simulation of succession in the forest ecosystem must be repeated several times (150 times in this study) in order to determine the central tendency of variations over time. The model has been parameterized for Scots pine, Norway spruce, birch ( Betula pendula Roth. and Betula pubescens Ehrh.), aspen ( Populus tremula L.) and grey alder ( Alnus incana Moench., Willd) growing between the latitudes N 60° and N 70° and longitudes E 20° and E 32° in Finland (Kellomäki et al. , 1992; Kellomäki and Kolström, 1993; Kolström, 1999). The model is run on an annual basis and the computations are applied to an area of 100 m 2 . A procedure for management includes thinning, fertiliza- tion, rotation length and harvesting of timber and energy biomass (foliage, branches, stumps and top part of stem not suitable for timber). The total amount of fertilizer (NT, kg ha − 1 ), which was added in a single fertilizing event, was expected to gradually affect the growth over several years, so that the effect decreased over time (and disappeared fi- nally). Annually, the fraction of fertilizer ( F ( k )) affecting the growth in the year k ...
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The impacts of alternative forest management scenarios and harvest intensities on climate change mitigation potential of forest biomass production, utilization and economic profitability of biomass production were studied in three boreal sub-regions in Finland over a 40-year period. Ecosystem modelling and life cycle assessment tools were used to c...
The aim of this study was to examine how intensified silviculture affects timber production (sawlogs and pulpwood) and its economic profitability (net present value [NPV], with 2 per cent interest rate) based on forest ecosystem model simulations. The study was conducted on Norway spruce and Scots pine stands located on medium-fertile upland forest...
Citations
... In turn, rotation lengths of 120 years in a forest area with initially normally distributed age structure have been found to produce the lowest emissions [7]. Intensive management of a single stand, including the use of nitrogen fertilizers, improved planting material, and high stocking density also increases the climate benefits of using energy biomass compared to the use of fossil-based energy under alternative rotation periods, due to increased carbon sequestration [9,[15][16][17][18][19][20]. However, the potential of forest management to increase carbon sequestration within a certain time frame also depends on the age structure of a forest area. ...
... The outputs of ecosystem model simulations [27] were utilized to estimate the annual net CO 2 exchanges (C net ) in the systems by using a life cycle assessment (LCA) tool [28]. The forest ecosystem model SIMA [15,16,27,29] was used to simulate the forest growth and development of the tree stands under the influences of temperature; the availability of light, soil water, and nitrogen; and the CO 2 concentration in the atmosphere. Trees may die randomly, but the probability of death increases with a decline in growth. ...
We investigated how the initial age structure of a managed, middle boreal (62°N), Norway spruce-dominated (Picea abies L. Karst.) forest area affects the net climate impact of using forest biomass for energy. The model-based analysis used a gap-type forest ecosystem model linked to a life cycle assessment (LCA) tool. The net climate impact of energy biomass refers to the difference in annual net CO2 exchange between the biosystem using forest biomass (logging residues from final felling) and the fossil (reference) system using coal. In the simulations over the 80-year period, the alternative initial age structures of the forest areas were (i) skewed to the right (dominated by young stands), (ii) normally distributed (dominated by middle-aged stands), (iii) skewed to the left (dominated by mature stands), and (iv) evenly distributed (same share of different age classes). The effects of management on net climate impacts were studied using current recommendations as a baseline with a fixed rotation period of 80 years. In alternative management scenarios, the volume of the growing stock was maintained 20% higher over the rotation compared to the baseline, and/or nitrogen fertilization was used to enhance carbon sequestration. According to the results, the initial age structure of the forest area affected largely the net climate impact of using energy biomass over time. An initially right-skewed age structure produced the highest climate benefits over the 80-year simulation period, in contrast to the left-skewed age structure. Furthermore, management that enhanced carbon sequestration increased the potential of energy biomass to replace coal, reducing CO2 emissions and enhancing climate change mitigation.
... 131,132 Other studies of the possibilities to intensify forest management (particularly in the boreal forests) confirm that stand management can increase both the C stocks and the biomass and timber production on the same piece of land. [133][134][135] To the extent that increased demand for forest bioenergy makes such measures feasible (i.e., they would not have taken place in a scenario without bioenergy demand), effects of changed forest management should be considered when evaluating the climate change mitigation benefit of forest bioenergy. This has implications for how evaluation frameworks should be designed. ...
The dedicated production of biomass crops and the collection of residues in agriculture and forestry can lead to undesirable negative impacts and it is crucial that practices are found that ensure that these impacts are avoided or mitigated as far as possible. This chapter concerns the use of biomass for energy and the connection between increased bioenergy use and land use change (LUC). Land use and LUC associated with bioenergy can lead to a multitude of environmental and socioeconomic consequences. The chapter focuses on the question whether greenhouse gas (GHG) emissions associated with LUC could undermine the climate change mitigation benefits of bioenergy. There are, however, several options for mitigating these emissions that can be implemented: development of bioenergy feedstock production systems that integrate with existing agriculture and forestry production, enhancement of land use productivity in agriculture and forestry in general, and legal protection of natural ecosystems.
... The SIMA model has been parameterised for Norway spruce, Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), and downy birch (Betula pubescens Ehrh.) growing throughout Finland (latitudes, 60°N and 70°N; longitudes, 20°E and 32°E). Previous predictions of the SIMA model have shown good agreement with measured volume growth on permanent sample plots of the National Forest Inventory (NFI) throughout Finland, parallel simulations made by empirical growth model Motti (see Hynynen et al. 2002; Matala et al. 2005 Matala et al. , 2006), and measured growth response of trees to nitrogen deposition (see, for example, Mäkipää et al. 1998, Matala et al. 2003, and Routa et al. 2011a, 2011b). ...
We studied regional effects of alternative climate change and management scenarios on timber production, its economic profitability (net present value (NPV), with 2% interest rate), and carbon stocks over a 90 year simulation period in Norway spruce (Picea abies (L.) Karst.) forests located in southern, central, and northern Finland. We also compared the results of optimised management plans (maximizing incomes) and fixed management scenarios. Business as usual (BAU) management recommendations were used as the basis for alternative management scenarios. The forest ecosystem model SIMA together with a forest optimisation tool was employed. To consider the uncertainties related to climate change, we applied two climate change scenarios (SRES B1 and SRES A2) in addition to the current climate. Results showed that timber production, NPV, and carbon stocks of forests would reduce in southern Finland, opposite to northern Finland, especially under the strong climate change scenario (SRES A2) compared with the current climate. In central Finland, climate change would have little effect. The use of optimised management plans also resulted in higher timber yield, NPV, and carbon stock of forests compared with the use of a single management scenario, regardless of forest region and climate scenario applied. In the future, we may need to modify the current BAU management recommendations to properly adapt to the changing climatic conditions.
Key words: climate warming, carbon balance, forest production, forest optimisation, economic profitability.
... Previous simulations with the SIMA model Routa et al. 2011aRouta et al. , 2011b have shown good agreement with the measured values of volume growth of the main tree species on the permanent sample plots of the National Forest Inventory (NFI) throughout Finland. Furthermore, parallel simulations with the empirical growth and yield model Motti (Hynynen et al. 2002) and the SIMA model have provided good agreement for the predicted volume growth both with and without nitrogen fertilization in Norway spruce (Kellomäki et al. 2005Routa et al. 2013). ...
... Forest management largely affects the yield of timber and energy biomass, but also the timing when wood products and energy biomass enter the technosystem to substitute for fossil-intensive materials and energy. For example, Eriksson et al. (2007), Sathre et al. (2010) and Routa et al. (2011b) have recommended the use of nitrogen fertilization to increase carbon sequestration of forests, and forest biomass production and utilization for materials and energy to reduce the net GHG emissions. Maintenance of higher stocking over the rotation will also increase the carbon sequestration and carbon stocks of forests compared to the baseline management, resulting in reduced radiative forcing. ...
... The model structure and parameterisation are described in detail in Kellomäki (1992a, b), Kolström (1998) and Kellomäki et al. (2008). The model has been previously validated in Kolström (1998), Kellomäki et al. (2008), Routa et al. (2011, and Mazziotta et al. (2014a). A scheme of the interactions between factors and processes in the model is given inFig. ...
Conservation strategies are often established without consideration of the impact of climate change. However, this impact is expected to threaten species and ecosystem persistence and to have dramatic effects towards the end of the 21st century. Landscape suitability for species under climate change is determined by several interacting factors including dispersal and human land use. Designing effective conservation strategies at regional scales to improve landscape suitability requires measuring the vulnerabilities of specific regions to climate change and determining their conservation capacities. Although methods for defining vulnerability categories are available, methods for doing this in a systematic, cost-effective way have not been identified. Here, we use an ecosystem model to define the potential resilience of the Finnish forest landscape by relating its current conservation capacity to its vulnerability to climate change. In applying this framework, we take into account the responses to climate change of a broad range of red-listed species with different niche requirements. This framework allowed us to identify four categories in which representation in the landscape varies among three IPCC emission scenarios (B1,low-; A1B,intermediate-; A2,high-emissions): a) susceptible (B1=24.7%, A1B=26.4%, A2=26.2%), the most intact forest landscapes vulnerable to climate change, requiring management for heterogeneity and resilience; b) resilient (B1=2.2%, A1B=0.5%, A2=0.6%), intact areas with low vulnerability that represent potential climate refugia and require conservation capacity maintenance; c) resistant (B1=6.7%, A1B=0.8%, A2=1.1%), landscapes with low current conservation capacity and low vulnerability that are suitable for restoration projects; d) sensitive (B1=66.4%, A1B=72.3%, A2=72.0%), low conservation capacity landscapes that are vulnerable and for which alternative conservation measures are required depending on the intensity of climate change. Our results indicate that the Finnish landscape is likely to be dominated by a very high proportion of sensitive and susceptible forest patches, thereby increasing uncertainty for landscape managers in the choice of conservation strategies.This article is protected by copyright. All rights reserved.
... Finnish simulation studies have indicated that profitability could be increased with integrated timber and forest energy production and higher stand densities (Routa et al. 2011), which in turn could decrease CO 2 emissions from the use of energy wood (Routa et al. 2012). Other possible means to increase both timber and forest energy would be increasing the rotation length and the growth rate of trees through fertilization and maintaining higher stocking (Pyörälä et al. 2012). ...
The review gives an overview of the increased utilization of forest biomass for energy. The emphasis is on Nordic countries, especially on Sweden and Finland with large biomass potentials and a high share of renewable energy in gross final energy consumption. The utilization and potential of forest chip sources such as logging residues, small-size tree stems and stumps that are normally not harvested in conventional harvesting are described. Environmental potential and impacts that may reduce the utilization of forest biomass are discussed based on recent publications. Finally, the review summarizes the future developments based on their relationship to policies, certifications and guidelines and forest owners' decisions.
... Each time such an event (e.g., death of an individual tree) is possible, the algorithm selects whether or not the event will take place by comparing a random number with the probability of occurrence of the event. The model has been previously validated with forest inventory data in Kolström (1998) and Routa et al. (2011. ...
... The model structure and parameterization have been described in detail (). Growth model validation has been detailed by Kolström (1998) and Routa et al. (2011. The simulations were repeated 10 times, a number of replicates proven sufficient by the abovementioned studies to determine the central tendency of demographic processes and variation around it (uncertainty). ...
Climate change represents today an important driver of species extinction the importance of which is increasing, acting in synergy with habitat destruction and fragmentation. Here, I studied the effects of climate change on the processes sustaining biodiversity in boreal forest in Finland via a forest ecosystem simulator. Furthermore I analysed the effect of management in altering these processes jointly with climate. Then I evaluated the roles of climate exposure and sensitivity in determining the vulnerability of forest species to climate change. I combined climate vulnerability with the current conservation capacity of the landscape to prioritize forest stands into categories of response to climate change for Finland. I associated each response category to adaptation measures, conservation and management actions to halt the loss of biodiversity induced by climate change. Finally I employed an optimization framework to allocate in cost-efficient way conservation and management actions in the landscape, with the goal of maximizing the habitat for biodiversity, under the assumption of long-term economic and ecological sustainability. The results of my thesis shed light on the mechanisms by which climate change and management modify habitat for forest biodiversity in boreal forest. My results predict that by the end of the 21st century there will be both an increase in the number of winners, i.e., species associated with dead wood gaining more habitat due to higher forest growth under climate change, and of losers, i.e., species which will face reduced habitat availability as a consequence of adjusting forest management to improved forest growth. The results of the prioritization indicate that the Finnish landscape is likely to be dominated by a high proportion of sensitive and susceptible forest patches, increasing uncertainty for landscape managers in the choice of conservation strategies. However the thorough use of an optimization framework may facilitate conservation managers, when dealing with limited resources, to face the challenges imposed by climate change for sustainability.
... The validation of the model with the parameter values for the main Finnish tree species has been discussed previously by Kellomäki et al. (2008) and Routa et al. (2011). A close correlation was found between measured growth values from the National Forest Inventory and those simulated with the model. ...
The present research examines the joint effects of climate change and management on the dead wood dynamics of the main tree species of the Finnish boreal forests via a forest ecosystem simulator. Tree processes are analyzed in stands subject to multiple biotic and abiotic environmental factors. A special focus is on the implications for biodiversity conservation thereof. Our results predict that in boreal forests, climate change will speed up tree growth and accumulation ending up in a higher stock of dead wood available as habitat for forest dwelling species, but the accumulation processes will be much smaller in the working landscape than in set-asides. Increased decomposition rates driven by climate change for silver birch and Norway spruce will likely reduce the time the dead wood stock is available for dead-wood associated species. While for silver birch the decomposition rate will be further increased in set aside in relation to stands under ordinary management, for Norway spruce set-asides can counterbalance the enhanced decomposition rate due to climate change thereby permitting a longer persistence of different decay stages of dead wood.
... Stand density also affects the growth and thus carbon stock in forests. Routa et al. (2011Routa et al. ( , 2012 showed that high stand density at precommercial stage increase the wood production in Finnish boreal forests. This actually implies that high stand density enhances forests growth and carbon sequestration. ...
The objective of this project is to discuss the role of forests in Nordic countries in climate change mitigation and discuss the possible roles of forests as a part of a cost-effective climate policy. The report aims to provide a comprehensive and easily digestible way to better understand the issue. The report includes a discussion on the role of forests for enhancing carbon stocks and carbon sinks in the Nordic countries. The extent of above- and below-ground biomass and their role as forests carbon sinks in Nordic forests is analysed. The use of wood in products, buildings and as bioenergy is examined. Finally the report presents emissions trading schemes from around the globe that allow offsets and credits from forest projects on them and provides an analysis on the feasibility of such a scheme for the Nordic region. The report has been commissioned by the Working Group on Environment and Economics under the Nordic Council of Ministers. The study was carried out by Indufor.
... Due to an expected increase of renewable energy in general consumption, the interest in wood use for energy purposes is renewed (Alam et al. 2012). It may result in using again denser spacing and more frequent thinning (Routa et al. 2011). ...
... Forest stand in Kozienice, Łąck and Parciaki plots was measured before the beginning of experiment (in 1997-1999). Following measurements in Kozienice plot took place in 2005 and2011;Łąck in 2003, 2007and Parciaki in 2003and Parciaki in , 2006and Parciaki in and 2012. Measurements on Janów Lubelski plot was performed every 5 years between 1976 and 2001, and then in 2007 and 2012. ...
The research aim was to evaluate the influence of different thinning methods on future crop tree growth.
Investigations were conducted on permanent Scots-pine experimental plots, established in 1960s and 1970s in
Kozienice, £¹ck, Parciaki and Janów Lubelski Forest Districts. To assess the response to thinning of future crop trees,
their dominance coefficients were used. These are defined as quotients for each given future crop tree diameter and
average stand diameter (WP1), the average dominant layer diameter (WP2) and the average diameter of 100 thickest
trees per hectare (WP3). The difference between each coefficient value at the beginning and at the end of the
measurement period was used as a measure of the thinning effect.
On Kozienice, £¹ck and Parciaki plots the differences between treatments were significant, especially in the period
after first thinning. The increase of WP3 coefficient occurred in a case of strong thinning – TS1 and TS2. On plot
Parciaki also the moderate thinning TU1 and TU2 had a significant influence on change of this coefficient. On plot
Janów Lubelski the influence of treatment has not been stated in the first 5-year period but in the next one.
Analyses of changes in the dominance coefficients confirmed the hypothesis that the WP3 coefficient is very useful
as it is the most stable indicator of future crop-tree position in a stand. On Kozienice, £¹ck and Parciaki plots
the significant differences between treatments were stated, especially in the period after first thinning.
The influence of thinning treatment on the plot Janów Lubelski was not considered for the first 5-year period but
in the next one. All reactions to thinning were slower on this plot, possibly because of the relatively poor site conditions.
This was a long-term effect.
The results obtained suggest that very intense thinning of Scots pine stands should only be implemented under a
restricted set of conditions – in healthy, not neglected, forest stands. Classical moderately-selective thinning is
preferable to intense thinning and is the most convenient option for pine stands.
