Lauri Valsta

Forest carbon sequestration and harvests in Scots pine stand under different climate and nitrogen deposition scenarios

Abstract In this study, effects of altered rotation length, nitrogen deposition and changing climate on harvest removal and carbon sequestration of forest, as well as on economic profitability of forestry, were assessed. This study was based on simulations with a gap-type forest succession model in the conditions that represent Scots pine stands in southern Finland. Both warmer climatic conditions and increased nitrogen deposition enhanced forest productivity and timber yield. This also shortened the optimum rotations based on mean annual yield and soil expectation value. The highest carbon stock in forests, i.e. the highest mean annual carbon stock in the forest over a rotation period, was achieved with long rotations and higher nitrogen deposition. However, a warmer climate had an opposite effect on the forest carbon stock, because enhanced decomposition of soil organic matter resulted in a lower carbon stock in the forest soil.

Climate change mitigation through increased wood use in the European construction sector—towards an integrated modelling framework

Using wood as a building material affects the carbon balance through several mechanisms. This paper describes a modelling approach that integrates a wood product substitution model, a global partial equilibrium model, a regional forest model and a stand-level model. Three different scenarios were compared with a business-as-usual scenario over a 23-year period (2008–2030). Two scenarios assumed an additional one million apartment flats per year will be built of wood instead of non-wood materials by 2030. These scenarios had little effect on markets and forest management and reduced annual carbon emissions by 0.2–0.5% of the total 1990 European GHG emissions. However, the scenarios are associated with high specific CO2 emission reductions per unit of wood used. The third scenario, an extreme assumption that all European countries will consume 1-m3 sawn wood per capita by 2030, had large effects on carbon emission, volumes and trade flows. The price changes of this scenario, however, also affected forest management in ways that greatly deviated from the partial equilibrium model projections. Our results suggest that increased wood construction will have a minor impact on forest management and forest carbon stocks. To analyse larger perturbations on the demand side, a market equilibrium model seems crucial. However, for that analytical system to work properly, the market and forest regional models must be better synchronized than here, in particular regarding assumptions on timber supply behaviour. Also, bioenergy as a commodity in market and forest models needs to be considered to study new market developments; those modules are currently missing.

Effects of initial stand states on optimal thinning regime and rotation of Picea abies stands

Abstract This study analysed the effects of young stand characteristics on optimal thinning regime and length of rotation periods for even-aged Norway spruce [Picea abies (L.) Karst.] stands. Stand development was based on a distance-independent, individual-tree growth model. The young stand data were collected from 12 well-stocked Norway spruce stands in southern Finland. Results showed that optimal thinning regimes and rotation period depend on site quality and initial stand characteristics. At the first thinning, optimal thinning type depended on initial density. Thinning from both ends of the diameter distribution turned out to be optimal for initially dense stands. At the second and subsequent thinnings, thinning from above was clearly superior. At a low interest rate, thinning from below was optimal for the first thinning regardless of stocking level. For the study data, optimal rotation periods varied from 61 to 92 years at 3% interest rate. The high variation in length of rotation period was due to the sensitivity of optimal length of rotation period to site qualities, initial stand structure and density.

Climate Change Mitigation Challenge for Wood Utilization—The Case of Finland

The urgent need to mitigate climate change invokes both opportunities and challenges for forest biomass utilization. Fossil fuels can be substituted by using wood products in place of alternative materials and energy, but wood harvesting reduces forest carbon sink and processing of wood products requires material and energy inputs. We assessed the extended life cycle carbon emissions considering substitution impacts for various wood utilization scenarios over 100 years from 2010 onward for Finland. The scenarios were based on various but constant wood utilization structures reflecting current and anticipated mix of wood utilization activities. We applied stochastic simulation to deal with the uncertainty in a number of input variables required. According to our analysis, the wood utilization decrease net carbon emissions with a probability lower than 40% for each of the studied scenarios. Furthermore, large emission reductions were exceptionally unlikely. The uncertainty of the results were influenced clearly the most by the reduction in the forest carbon sink. There is a significant trade-off between avoiding emissions through fossil fuel substitution and reduction in forest carbon sink due to wood harvesting. This creates a major challenge for forest management practices and wood utilization activities in responding to ambitious climate change mitigation targets.

Use of Forests and Wood Products to Mitigate Climate Change

The increased concentrations of greenhouse gases in the atmosphere are one of the most severe current environmental problems. The annual atmospheric increase of carbon is estimated to be 3.2 Pg (IPCC 2001, p. 190). In comparison, the annual harvest of roundwood is about 3.5 billion cubic meters (FAO 2006) and contains approximately 0.8 Pg carbon in roundwood (assuming 0.23 Mg C/m3) and is, hence, significant also for the global carbon balance. The estimated amount of carbon in forested areas is approximately 650–1200 Pg (House et al. 2003; Grace 2004; FAO 2006), most of which is located in forest soils. Recent aboveground biomass estimates are between 257 Pg (Kauppi 2003) and 359 Pg (IPCC 2001). Given the large amounts, even a small proportional change is influential.

Economic Evaluation of Uneven-aged Management

Even-aged stands or plantations have been the most common stand type in forest economics research. This is not surprising because the majority of active silviculture in traditional forestry countries has been based on the even-aged management system. Parallel to the ‘normal forest’ concept of even-aged forestry, the sustainable diameter distribution of uneven-aged stands has a considerable research history. The advent of more flexible stand management principles, such as Continuous Cover Forestry or Any-aged Management, calls for more careful economic analysis of stand management options.

Forest owners’ views on storing carbon in their forests

ABSTRACT Given the high percentage of private forest ownership in Finland, family forest owners have an important role in mitigating climate change. The study aims to explore Finnish family forest owners’ perceptions on climate change and their opinions on increasing carbon storage in their forests through new kinds of management activities and policy instruments. The data consists of thematic face-to-face interviews among Helsinki metropolitan area forest owners (n = 15). These city-dwellers were expected to be more aware of and more interested in climate change mitigation than forest owners at large. Forests as carbon fluxes appear to be a familiar concept to most of the forest owners, but carbon storage in their own forests was a new idea. Four types concerning forest owners’ view on storing carbon in their forests could be identified. The Pioneer utilizes forestland versatilely and has already adopted practices to mitigate climate change. The Potential is concerned about climate change, but this is not seen in forest practices applied. The Resistant is generally aware of climate change but sees a fundamental contradiction between carbon storing and wood production. The Indifferent Owner believes that climate change is taking place but does not acknowledge a relation between climate change and the owner’s forests.