Is the well-being of future generations being compromised to meet the needs of the present population? This question came up in the Bruntland report in 1987, and it has led to the setting of the 2030 goals of sustainable development (SDG) by the UN. While the concept of sustainability has been prevalent in forestry since the 18th century, it has been interpreted in many ways since then.
Traditionally, the sustainability of forestry has been examined from the standpoint of maintaining wood production, i.e. from an economic perspective. Sustainability indicators include, but are not limited to, forest area, ratio of fellings and increment or maximum sustained yield. The maximum sustained yield is a measure of the maximum level of current fellings that can be sustained into the future.
These indicators crystallize the most prominent problem when considering sustainability: when we have more than one indicator, the use of forests can be deemed either sustainable or non-sustainable depending on which indicators are selected and what weight is assigned to them. For instance, in Finland, the forest area is declining due to the construction of roads and buildings and for clearing forests in order to obtain new farmland. On the other hand, the increment is clearly higher than fellings. It is not possible to define objective science-based weights for these indicators and, thus, the relative importance of them depends on the values prevailing in the society.
Forestry is more than just wood production
Sustainability that only considers the economic aspects is clearly not enough. The use of forests should also be ecologically, socially and culturally sustainable. The pan-European criteria and indicators, which are monitored on a national level, can cater to this need for their part. Forest Europe, otherwise known as the Ministerial Conference on the Protection of Forests in Europe, is reporting on the state of European forests (SOEF2015), while the European Environment Agency is reporting on the state of the environment (SOER2020) based on the criteria and indicators selected for this purpose.
In Finland, about 25% of the total productive and poorly productive forest land area has restrictions on forest management.
The forest-related indicators being monitored under these processes include, for example the forest area, total volume, forest health and vitality, increment and fellings and natural products. Another indicator is the area with a forest management plan, which is also one of the UN sustainable development indicators for forests. Indicators being used to monitor the biodiversity of forests include, for example tree species composition, area of regenerated forests, naturalness, volume of deadwood, landscape structure, occurrence of threatened species, and protected forests.
Maximum sustained yield is only one indicator for sustainability
Luke produces information on the maximum sustained yield primarily for large-scale forest planning. In public debate, this measure has been criticized for not taking the ecological and social sustainability into account. It is typically seen as describing the sustainability only from a wood production point of view. When the measure was first introduced (it was first published in Germany in 1795 by G.L. Hartig), its scope only covered the wood production perspective. Nowadays, however, maximum sustained yield also considers social and ecological sustainability with a weight that reflects the decisions made in the society for enhancing social and ecological sustainability.
This is a result of the way the measure is calculated: all areas in which the forest management is restricted due to other uses of land, such as protection and recreation, are accounted for. In Finland, about 25% of the total productive and poorly productive forest land area has restrictions on forest management. These restrictions obviously include all forests protected by law (such as national parks), but they also include areas in which any cutting or clear-cutting is restricted due to the known decisions of the forest owner.
The choices made in forestry are based on the values prevailing in the society.
Many areas governed by the State Forest Enterprise Metsähallitus are included in that category. In addition, the restrictions also cover proposed protected areas, even though this protection has not yet been officially decided upon. Additionally, these calculations consider all the silvicultural measures which have been recommended for enhancing ecological or social sustainability, such as recommendations for retention trees. When all the restrictions are taken into account, the resulting maximum sustained yield is much lower than it would be without these restrictions.
Even though the maximum sustained yield covers many aspects of ecological and social sustainability, it does not define sustainable forestry any more than any of the other potential measures. Furthermore, it is not meant as a goal for future fellings, but is simply one indicator for sustainability. Similar measures could be calculated for other ecosystem services, too.
Sustainability of forestry is defined in mutual negotiations
The choices made in forestry are based on the values prevailing in the society. These values are under constant public debate in Finland and elsewhere. Attempting to increase the production of one or more ecosystem services usually leads to a situation where there is a reduction in some other ecosystem service. This is called the trade-off between the services. These trade-offs are important, especially when politicians and decision makers discuss the mutual importance of potential goals, such as timber production, carbon sequestration, nature-based tourism, or biodiversity. The role of research in this process, is to produce information on these services and their trade-offs.
Luke has developed a tool for visualising these trade-offs in different forest use scenarios: Forest Indicator. In the Forest Indicator, it is possible to address, for example, the impacts of increased or reduced level of fellings on other ecosystem services. It would also be possible to visualise the impact of increased or reduced level of forest management restrictions. Furthermore, research has a role in analysing the effect of forest (and other relevant) policies on different dimensions of sustainability and to produce information for developing new regulations or compensation policies. The weight of importance placed on the different dimensions of sustainability in the future, belongs in the realm of politicians as they deliberate on the related laws but will also depend on forest owners and what they consider to be paramount in their own forests.
The blog post has also been published on Forest Academy’s website.