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The Paris Agreement and the European Green Deal set ambitious climate change mitigation goals. In order to achieve these goals and offset the emissions of all other sectors significant additional carbon sequestration is needed in the land use sector. The capacity of the land use sector and especially forests to remove carbon dioxide from the atmosphere is key in climate change mitigation pathways. Well planned forest industry related measures can significantly increase carbon sequestration in living biomass as well as in harvested wood products. In our study we investigated the climate change mitigation effects of forest management systems and nature conservation conducting a Greenhouse Gas Inventory-like analysis on Hungarian forests using a forest management system and protection status specific breakdown and considering only the biomass pool. Our main conclusion was that under similar yield class distribution logging intensity and carbon sequestration are not inversely proportional. We observed that non-protected forests achieve higher net carbon sink under a higher logging intensity. Regarding forest management systems we observed significantly higher net carbon sink under transitional forest management than what was found for all other management systems. Continuous cover management and non-production forest management did not show significantly different carbon fluxes.

Woody biomass is a key raw material of the circular bioeconomy, and its use can contribute considerably to achieving sustainability goals and carbon neutrality. The use of timber can foster climate change mitigation through long-term carbon storage and through the substitution of fossil products and fossil fuels. Sustainable forest management is meant to balance the contradictory goals of economic efficiency and nature conservation with careful planning and foresight. Consequently, it is important to assess the amount of timber that can be harvested without compromising sustainability. In our study, we examined the amount of wood stock accumulated in overmature stands in Hungary. Overmature stands are defined as those stands where the actual age of the stand is over its cutting age prescribed by the Forest Authority. 11.5 % of the standing volume in Hungary is overmature, and the wood stock of overmature stands has increased by more than 250 % in the last 40 y. Our results point out that a significant surplus of timber ripe for cutting is stored in overmature stands. The importance of this unused wood stock reserve is enormous, as it is a basis for meeting the growing timber demand in a sustainable way. In our study, we present the most important characteristics of the overmature black locust (Robinia pseudoacacia), which stands as a representative example. The authors conclude that the mobilization of the unused wood stock reserve and the utilization of the additional harvest possibility will be among the most important challenges of the Hungarian forest industry in the upcoming decades. The harvesting potential could be unlocked by professional integration and technical assistance provided to forest managers and wood industry enterprises based on GIS applications. Geographically explicit information on the amount and value of wood stocks available for harvest could be a basis for creating a new type of entrepreneurial culture and new ways of providing forest-related services.

As forest-based climate change mitigation has become a crucial element of international climate policy it is of increasing importance to understand the processes leading to the carbon offsetting capacity of the sector. In our study, we assessed the climate benefits of contrasting forest management strategies: decreasing harvest and enlarging the forest carbon stock, or increasing harvest to increase carbon uptake, wood product carbon pools, and substitution effects. We developed the Forest Industry Carbon Model (FICM) which is a new carbon accounting tool covering forest biomass, dead organic matter, soil, and harvested wood product pools, as well as avoided emissions through product and energy substitution. We modeled the carbon balance of the Hungarian forest industry under three different scenarios. In the business as usual (BAU) scenario, we assumed no changes in the current harvest and afforestation levels. In the extensification scenario, we assumed that the harvest and afforestation levels drop to half, while in the intensification scenario, we assumed an increase in afforestation, improved industrial wood assortments, and a gradual increase in logging, reaching the highest level as per sustainability criteria by 2050. Our results show that the intensification scenario is characterized by the largest net removals and the maximized product and energy substitution effects. By 2050, the net forest industry carbon balance reaches −8447 kt CO2 eq under the BAU scenario, while −7011 kt CO2 eq is reached under the extensification scenario and −22,135 kt CO2 eq is reached under the intensification scenario. Although substitution effects are not accounted for under the land-based (LULUCF) sector in the greenhouse gas inventory, the emission reductions in the industry and energy sectors have beneficial effects on the national carbon balance. Modeling results show that the 2030 LULUCF greenhouse gas removal target set by EU legislation for Hungary is reached under the intensification scenario. To achieve this outcome, widespread innovation is needed in the wood sector. The modeling results show that nonutilization of forests can only be a very short-term solution; however, its favorable effects will be reversed by 2050 resulting in additional emissions compared to the BAU scenario.

The land use sector is a crucial pillar in achieving the EU climate goals set for 2050. A significant part of the climate change mitigation potential of the land use sector is inherent to agroforestry. Windbreaks are important agroforestry elements of Hungarian agricultural landscapes. The new and improved agroforestry subsidy system may positively affect the extension of windbreaks in Hungary, making it relevant to assess their carbon sequestration potential. In our study, we examined the carbon sequestration of windbreaks at the country level and in two sample areas of 24,000 hectares based on National Forestry Database volume stock data, as well as information collected from the Hungarian Forest Cover Map using orthophoto interpretation. We estimated the total annual carbon sequestration realized in the aboveground biomass pool of Hungarian windbreaks to be −33.1 ktCO2/year, which is 0.67% of the total annual carbon sequestration of the aboveground biomass pool of all Hungarian forests, as reported by the Hungarian Greenhouse Gas Inventory. On the other hand, according to our estimate, the weighted mean annual carbon sequestration in the aboveground biomass of windbreaks was −2.4 tCO2/ha/year in the 2010–2020 period. This value is very close to the average mean annual carbon sequestration per hectare value of all forests, as reported by the Hungarian Greenhouse Gas Inventory. This means that planting a given area of windbreaks in between agricultural fields can have similar climate change mitigation effects as planting forests in the same given area.

The demand for woody biomass as a key raw material of the developing circular bioeconomy is expected to increase. This has led to the need of increased timber productivity and the search for new procurement methods, new assortments, and innovative supply chains. Timber is regarded as a climate-friendly resource, which can contribute to climate change mitigation through long-term carbon storage and through the substitution of fossil products and fossil fuels. Thus, it is of high importance to assess the amount of timber that can be harvested without compromising sustainability concerns. In this paper, we examined the amount of the wood stock accumulated in overmature stands in Hungary. We define overmature stands being those stands where the actual age of the stand is over its cutting age prescribed by the forest authority. According to our results, 11.5% of the standing volume in Hungary is overmature, and the wood stock of overmature stands has increased by more than 250% in the last 40 years. The importance of the overmature forests is enormous, as they represent an unused wood stock reserve, which could be available to meet the growing demand for timber. In our study, we also conducted a simple yield table-based projection on the maximum amount of timber available for harvest in the period 2020–2100 based on the data of the national forestry database and the cutting ages prescribed by the forest authority in the forest management plans. According to our results, even without new afforestation, more timber becomes available for harvest annually in the 2020–2100 period than the level of the average harvests of the last five historic years. In the 2020–2050 period, an additional 56% of timber is projected to become available for harvest as a maximum. This means a maximum additional potential of 4059 thousand m3, even without the harvesting of the stands, which were already overmature in the starting year of the projection. In the first part of the projection period, industrial wood available for harvest is forecasted to be above the average historic level of industrial wood production. However, in the second part of the projection period, the industrial wood yield shows a decreasing tendency and even drops below the 2017–2021 average. The decreasing availability of industrial roundwood in the second part of the projection period points out the importance of innovation in the wood industry. The inclusion of drought tolerant species, which are nowadays less used for industrial purposes seems inevitable in the production of high-quality wood products.

To determine the optimum time to harvest the trees is one of the most interesting problems in the economics of forest resources. It is highly debated whether forests in the Northern hemisphere should be used as carbon sinks or harvested more for long- or short-term wood use for carbon storage in long-lived wood products and for the use of bioenergy. In our study we examined the trend of the cutting ages by tree species, ownership and function in the period of 2006–2021 based on the data of the National Forestry Database (NFD). We also examined whether any changes in the effective rotation linked to the change of the Hungarian Forest Act in 2017 could be observed. We concluded that there were two main sub-groups in the case of which different trends applied. In the case of state-owned forests and indigenous species with a long rotation period, the actual harvesting ages had an increasing trend in the last fifteen years, while in the case of some species with short rotation periods and lower levels of naturalness, the cutting ages in private forests had a decreasing trend. The rotation period of black locust (Robinia pseudoacacia) showed a decreasing trend with a significant decrease in private production forests between years 2016 and 2021. This implies that since the more permissive regulation, the management of private black locust stands has moved towards the economically more profitable 20 years rotation cycle. We concluded that the new Forest Act of 2017 can be regarded as an important step towards the separation of forest functions, which means that the role of state-owned forests and forests with high nature conservation value is to protect biodiversity, provide ecosystem services and mitigate climate change through carbon storage in trees, dead wood and in the soil, while the role of forest plantations and forests with lower level of naturalness is to provide timber which is a climate-friendly resource, and which can contribute to climate change mitigation through long-term carbon storage in wood products, wooden buildings and through the substitution of fossil products and fossil fuels.

As wood products in use store carbon and can contribute to reducing the concentration of atmospheric CO2, the improved and enhanced use of wood products can be a successful measure in climate change mitigation. This study estimates the amount of carbon stored in the Hungarian harvested wood product (HWP) pool and the CO2 emissions and removals of the pool. According to our results, the total carbon stock of the Hungarian HWP pool is continuously increasing. We estimated the total carbon stock of the HWP pool to be 17,306 kt C in the year 2020. Our results show that the HWP pool in Hungary is a carbon sink in most parts of the time series, with some years where it turns to a source of emissions. We carried out a simple projection up to 2070, assuming a constant inflow for the projected years that is equal to the average inflow of the last five historic years. This resulted in a decreasing trend in CO2 removals, with removals already very close to zero in 2070. We concluded that in order to achieve significant future carbon sinks in the HWP pool technological improvements are needed, such as increasing the lifetime of the wood products and expanding the carbon storage capacity of wood products by reusing and recycling wood in a cascade system.

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