• Energy Research

The belief that trees have begun growing more rapidly in recent years was examined in Scots pine (Pinus sylvestris L.) forests, a dominant forest type in Lithuania. The largest, pre-dominant pine trees, with a diameter at breast height exceeding 50 cm, were selected for analysis in this study; these were growing in three experimental overly-mature stands located in different parts of Lithuania (north-eastern, western and seaside). We hypothesized that if the annual tree increment has increased in recent years, then the largest trees in the stand should regularly demonstrate this characteristic first of all. The data collected for this study confirmed that since the 1980 growing season the annual increment of the pine trees analysed here has increased. The causes of this rapid growth were higher air temperatures during the dormant period and, to a lesser extent, the higher temperatures from May through August. The effect of precipitation was negligible. A 30-year long data set on acidifying pollutants allowed us to detect significant effect of reduced SO2 concentration and sulphur deposition as well as gradually increased ammonia deposition on the increased annual basal area increment of pine trees over the last 30 year long period. Multiple regression analysis indicated that meteorological parameters can explain up to 50% of the observed increase in the growth rate of Scots pine in Lithuania; meanwhile the presence of acidifying species can account for an additional 30%. However, the pollution data set (20-30 years) was insufficiently long to be compared with the meteorological data. Therefore we were unable to distinguish whether the recent decrease in pollution or global warming resulted in the increases in tree growth rates more significant.

For forest sustainability and vulnerability assessment, the landscape scale is considered to be more and more relevant as the stand level approaches its known limitations. This review, which describes the main forest landscape simulation tools used in the 20 European case studies of the European project “Future-oriented integrated management of European forest landscapes” (INTEGRAL), gives an update on existing decision support tools to run landscape simulation from Mediterranean to boreal ecosystems. The main growth models and software available in Europe are described, and the strengths and weaknesses of different approaches are discussed. Trades-offs between input efforts and output are illustrated. Recommendations for the selection of a forest landscape simulator are given. The paper concludes by describing the need to have tools that are able to cope with climate change and the need to build more robust indicators for assessment of forest landscape sustainability and vulnerability.

Intensified forestry can be seen as a solution to climate change mitigation and securing energy supply, increasing the production of forest bioenergy feedstock as a substitution for fossil fuels. However, it may come with detrimental impacts on forest biodiversity, especially related to older forests. The aim of this study was to assess the sustainability of intensified forestry from climate-energy and biodiversity perspectives, targeting forest bird species. For this purpose, we applied the Landscape simulation and Ecological Assessment (LEcA) tool to the study area of Lithuania, having high ambitions for renewables and high forest biodiversity. With LEcA, we simulated forest growth and management for 100 years with two forest management strategies: Business As Usual (BAU) and Intensive forestry (INT), the latter with the purpose to fulfil renewable energy goals. With both strategies, the biomass yields increased well above the yields of the reference year, while the biodiversity indicators related to forest bird habitat to different degrees show the opposite, with lower levels than for the reference year. Furthermore, Strategy INT resulted in small-to-no benefits in the long run concerning potential biomass harvesting, while substantially affecting the biodiversity indicators negatively. The model results have the potential to inform policy and forest management planning concerning several sustainability goals simultaneously.

Research Highlights: Validating modelling approach which combines global framework conditions in the form of climate and policy scenarios with the use of forest decision support system to assess climate change impacts on the sustainability of forest management. Background and Objectives: Forests and forestry have been confirmed to be sensitive to climate. On the other hand, human efforts to mitigate climate change influence forests and forest management. To facilitate the evaluation of future sustainability of forest management, decision support systems are applied. Our aims are to: (1) Adopt and validate decision support tool to incorporate climate change and its mitigation impacts on forest growth, global timber demands and prices for simulating future trends of forest ecosystem services in Lithuania, (2) determine the magnitude and spatial patterns of climate change effects on Lithuanian forests and forest management in the future, supposing that current forestry practices are continued. Materials and Methods: Upgraded version of Lithuanian forestry simulator Kupolis was used to model the development of all forests in the country until 2120 under management conditions of three climate change scenarios. Selected stand-level forest and forest management characteristics were aggregated to the level of regional branches of the State Forest Enterprise and analyzed for the spatial and temporal patterns of climate change effects. Results: Increased forest growth under a warmer future climate resulted in larger tree dimensions, volumes of growing stock, naturally dying trees, harvested assortments, and also higher profits from forestry activities. Negative impacts were detected for the share of broadleaved tree species in the standing volume and the tree species diversity. Climate change effects resulted in spatially clustered patterns—increasing stand productivity, and amounts of harvested timber were concentrated in the regions with dominating coniferous species, while the same areas were exposed to negative dynamics of biodiversity-related forest attributes. Current forest characteristics explained 70% or more of the variance of climate change effects on key forest and forest management attributes. Conclusions: Using forest decision support systems, climate change scenarios and considering the balance of delivered ecosystem services is suggested as a methodological framework for validating forest management alternatives aiming for more adaptiveness in Lithuanian forestry.

Europe's forests provide vital habitat for biodiversity and essential ecosystem services whose provision must be sustained or enhanced over the coming century. However, the potential to secure or increase forest ecosystem services, while securing the habitat requirements of taxa remains unclear, especially within the context of uncertain climate and socio-economic developments. To tease out the associated trade-offs and synergies, we used 10 case study landscapes within nine countries throughout Europe. Starting with the current status of the forests in the case study landscapes, we simulated forest development 100 years into the future. Simulations were embedded in three combined climate and socio-economic frame scenarios based on global and European policies which varied in their climate change mitigation efficiency. Scenarios were translated into country specific projections of climate variables, and resultant demands for wood products. Forest management regimes were projected to vary in response to these scenarios at local scales. The specific combinations of alternative forest management practices were based on parallel research and input from local forest stakeholders. For each case study, a specific forest growth simulator was used. In general, the climate scenarios applied did not cause fundamentally different ecosystem service outputs at the case study level. Our results revealed almost no reduction in outcomes for biodiversity indicators with an increase in wood production, and in some cases synergistic results occurred when diversity was actively promoted as part of the management concept. Net carbon uptake was not strongly correlated with biodiversity, indicating that biodiversity-friendly forest management doesn't need to curtail carbon sequestration. Notably, we obtained heterogeneous results for the relation between sustainable wood production and net carbon uptake. Most scenarios resulted in a more or less reduced net carbon uptake over the long term, often due to stand age class distribution shifts. Levels of sustainable wood production varied widely during the simulation period, from significant increases (Sweden, Lithuania) to minor changes (Slovakia, Turkey) and slight decreases (Ireland, Netherlands). We place our results within the larger context of European forest policy and the challenges of simulating and contrasting forest biodiversity and the ecosystem services that societies depend on.

Demands on forest bioenergy feedstock are expected to increase in many countries due to climate change mitigation. However, sustainable use of forest biomass resources can be ensured only if local and landscape conditions are taken into account, linking energy use to its resource base. The aim of this study was to analyse the forest biomass potential for Lithuania's energy pathways, while comparing the projected demand of forest bioenergy feedstock with resource projections. This was performed using the Landscape simulation and Ecological Assessment (LEcA) tool and the energy model MESSAGE. Biomass demand can be met up to 2050, after which demands under a Biomass Low pathway can still be met by the domestic forest resource if other wood uses are reduced, while Biomass High leads to a biomass deficit regarding domestic forest resources. Information exchange between the energy model and the LEcA tool enables an integrated sustainability assessment, and may contribute to a sustainable and efficient use of forest as a bioenergy feedstock resource. Keywords: Forest bioenergy feedstock, Environmental restrictions, Resource efficiency, Integrated resource assessment, Integrated sustainability assessment