Forest fire in Sweden - a story of successful introduction of restoration

Fires is a good servant but a bad master (Finnish proverb)

The boreal forest landscape in northern Europe has historically been shaped by forest fire. It created multi-cohort stands dominated by pine on dry ground and initiated a successional sequence including a distinct deciduous stage in mesic and moist forests. Only really wet stands constituted fire-refugia. The understanding of fire history and how it shaped the forest landscape was scientifically highlighted in Sweden as late as in the 1970s. The seminal paper by Zackrisson (1977)[1] is the first landscape level analysis from Fennoscandia. Zackrisson showed than on average about 1% of the forests burned every year. Other studies have since then repeatedly confirmed the importance of forest fire in boreal forests. (e.g. Niklasson & Granström 2000[2]). These studies also highlighted the role of humans in the fire dynamics. Prior to human settlement, most fires were very large, but somewhat less frequent, while with humans in the landscape, fire frequency increase, but dominated by smaller fires. However, despite this shift in size and frequency of fires, up till the mid-1800s the annual area burned remained around 1%.

The study by Zackrisson (1977) convincingly showed that about 1% of the forest area burned annually until the mid-1850s

As the value of forest resources became evident through a growing forest industry during the 1800s, large scale fire prevention measures were implemented. This included building a large ranging network of towers which were manned during dry periods and with an associated developed fire suppression system. With the expansion of an extensive forest road network, fire management became even more effective. This resulted in a very effective suppression of fires and with a fire frequency several order of magnitude lower than in the preceding centuries.

Fires made a short comeback in the mid-1900s but then as a method to promote forest regeneration after clearcut harvest. These controlled fires ensured good tree regeneration on dryer soils and was frequently used up till the early 1970s. With increasing use of mechanized soil preparation this practice was abandoned.

The loss of fire as a natural disturbance regime and the associated effects on biodiversity sparked an interest among primarily researchers to re-introduce fire to secure habitat for fire associated species and to restore the forest structure typical for boreal pine forests. Initially this faced significant resistance among forest managers, the general public and also from conservation authorities. The risks associated with fire was one concern, but also the idea of actively manage forests for conservation was questioned. Within the Swedish EPA the main philosophy was that protected areas should be set aside for free development and that nature knows best how to develop on its own.  The understanding that human influence carries a temporal legacy and that natural process are missing was not fully realized. Yet, researchers and to some extent environmental organizations kept arguing that we are losing a formerly dominant forest types and with negative effects on associated species.

This led to a few attempts to use fire as a restoration tool in the early 1990s and provided examples on that it is possible to use fire for restoration and that declining species positively respond to burned areas. Two parallel processes resulted in a shift in attitude and has resulted in an increasing use of restoration fire.

A recently burned pine forest in norther Sweden. Although black and apparently dead, most of the pine trees survived the fires and ground vegetation recovers rapidly

During the 1990s the first FSC standards were developed and included an obligation for certified forest owners to burn an area corresponding to 5% of their annual harvest area. This provided a voluntary incentive to burn and resulted in the development of trained staff capable of safely burning forests. In parallel to this, the Swedish EPA developed new policies and guidelines for active management of protected areas and hence provided formal support to the regional county administrations for using fire as a conservation tool.

At present restoration fire is seen as a well-established conservation tool and normally considered when devising management plans for protected areas. Major financial support has recently been provided through EU LifeProject funding (LifeTaiga) and strongly supported collaboration among the County Administrations throughout Sweden. This collaboration has improved the practical skills in performing safe and appropriate fires. Within the FSC, the standard has been further developed and providing incentives for restoration fires of high quality. This include a multiplier for the 5% target so that burning tree covered areas and in combination with voluntary set-aside areas can receive a multiplier of up to 3, meaning in practice that the area required to be burned becomes smaller when fires that better support biodiversity are performed.

The fungi Geopyxis carbonaria is an example of a species that is strongly connected to recently burned forests

This short overview shows that when scientific knowledge on forest history, forest dynamics and the requirements for protecting biodiversity is combined with policy process, voluntary commitment and financial support, restoration can be successfully implemented even when initial resistance was significant.

[1] Zackrisson, O. 1977. Influence of forest fires on the north Swedish boreal forests. Oikos, 29: 22-32

[2] Niklasson, M. & Granström, A. 2000. Number and sizes of fires: Long-term spatially explicit fire history in a Swedish boreal landscape. Ecology 81: 1484-1499