Mixed forest

Even harsh forests are rich in biodiversity


In terms of nature’s biodiversity, Finland is quite a harsh land. There is only a small amount of tree species that grow here natively: four conifer and 27 deciduous species.


Finland belongs to the boreal zone, which has about a quarter of the earth's forest area, one-third of the forest resources and half of the conifers. It is therefore not surprising that the most important Finnish native – or indigenous – tree species are pine, spruce, birch, aspen and alder. A characteristic feature of Finnish forests is that even natively they tend to grow as a one-species forest, such as pines on dry heaths. The share of deciduous trees is about one-fifth of Finland's total volume of growing stock, and they usually grow in mixed forest.

Native tree species are important to the ecosystem and biodiversity. About half of the species found in Finland is forest species, as they are adapted to using Finnish trees – that have grown here for thousands of years – as nutriment, for nesting or breeding ground.

A common thought is that forestry is balancing between economic productivity and biodiversity. However, this is not the case, since most of the Finnish forest species live normally in commercial forests.


Forest renewal crystallises sustainability

Renewal of forests with native trees is important because it ensures the preservation of the species’ habitats. According to the forest management guidelines, less common types of wood such as precious hardwood trees are saved. A sure way to renew forests is by planting seedlings. Metsä Group plants four seedlings for every harvested tree which ensures that there will be forests for future generations as well.

From where do the seedlings come from? From domestic nurseries. For example in Finland, their operations, and health and quality of the seedlings are supervised by the Finnish Food Safety Authority Evira. Since the Finnish tree species have grown in Finland for thousands of years, the species have adapted to a particular climatic growth area. So if a tree is planted even two hundred kilometres too north, it continues to grow later than the local trees, and the southern tree can get bitten by frost. This exposes the trees to destruction.


Diversity is preserved with certification and cooperation with WWF Finland

The Finnish forest law is the foundation for biodiversity in Finland. The symbol of biodiversity for the markets is certification. Forest certification, for example, requires that a certain amount of saving trees are left to the logging site to form habitats for species who live on dead and decaying wood. At Metsä Group, 84% of used wood is certified.

Metsä Group promotes forest biodiversity with WWF Finland with management of herb-rich forests and sunlit habitats, and burning retention trees. Herb-rich forests and sunlit habitats are important because two-thirds of Finland's endangered forest species use them as the primary habitat. Some rare species, in turn, favour charred trees, which is why burning increases diversity. Therefore forest management has a significant role in safeguarding the diversity – also according to WWF Finland. WWF Finland’s Secretary General Liisa Rohweder commented in Metsä Group's Sustainability Report as follows:
"By cooperating with Metsä Group, we get to influence the forestry practices, which play a key role in safeguarding the biodiversity values of for example, the sunlit habitats and herb-rich forests."

Metsä Group is also taking part in WWF's Forest Challenge, where people are invited to explore WWF's Forest Management Guide. The guide contains the most important methods in commercial forest management. The guide is a useful tool for Metsä Group when planning harvesting and nature management measures together with forest-owners.

Biodiversity from pines to moose

          
 

Pine, Pinus sylvestris
The pine requires a lot of light and thrives in dry heaths. It grows rapidly and has deep roots that makes them almost storm-proof. Pines are highly resistant to other damages as well, but in cultured seedling stands, moose, insects and voles can do damage.

Spruce, Picea abies
The best growth place for spruce is fresh and nutritious. Spruce seedlings thrive in the shade, and ground vegetation often disappears from older trees because the branches give strong shading and the needles have acid. Moose, moles or hares don't eat spruces because they taste bad. Instead, the cause for biggest destruction is by a fungus that rots the trunk.

Birch, Betula pubescens and Betula pendula

Finland has several species of birches, including downy birch that thrives in moister places than silver birch.

Marshy forests, water-fronts, fields and road edges are where downy birch grows. Silver birch – Finnish national tree – is a pioneer tree that grows as the first tree on logging sites. It thrives in dry, fresh and lit forests. Moose and moles cause the most destruction for newly planted birches.

Aspen, Populus tremula
Aspen grows most handsome in lit, dry and fresh forests. Aspens are often left as retention trees to logging site, as they are important for biodiversity. Elderly aspens rot from the inside, which makes them excellent nesting trees for birds and other species. Aspen provides a habitat for various species – there are up to 350 species of fungi, lichens and insects that can live on one. In addition, aspens are a favourite dish for moose.

Alder, Alnus incana and Alnus glutinosa
Grey alder enjoys plenty of natural light on water-fronts and roadsides. Grey alder often begin to decay only at 50 years' of age, which is why they are important for biodiversity. Black alder grows best in nutritious places and water-fronts. A specific type of fungi live in their roots that bind nitrogen. Therefore, alders don't recover chlorophyll in the fall, but the leaves fall in green. This way a part of the nitrogen is released to the ground to improve the surrounding soil.

In Finland, wolves, wolverines, bears and moose live in the forests – you may run into one while berry-picking.

Moose, Alces alces, is the largest mammal in Finland, the most important game animal and the king of the forests. Oh, and Metsä Group's symbol, even though they cause significant damage to forestry with their food preferences. Moose eat according to the season, ranging from trees and bushes, twigs and shoots, to aspen, rowan, willow and birch, and pine and juniper during the winter. Moose cause the worst damage in pine and birch seeding stands in mid and late winter, but to pine and hardwood seedlings also, especially in the summer and autumn. Pine is the most important winter food, while in summer the priority is silver birch. A large moose can eat up to 50 kilogrammes on a summer day. When there is room to choose from, moose's smell and taste buds tell which plant has the most nutrients and the least harmful defence substances. These control moose's preferences.

 

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