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In Finnish forestry, there is a need to diversify the selection of tree species in order to adapt to climate change and to maintain the biodiversity of forest nature. A diverse range of tree species serves as insurance for an uncertain future. One way to increase diversity is to promote the use of domestic, little-cultivated noble broadleaved tree species and black alder (Alnus glutinosa).
Noble broadleaved trees are species that, when growing on suitable sites and managed properly, often produce valuable timber, but are generally quite rare in Finnish forests. The reason why noble broadleaved trees are relatively rare in Finland is that they require highly favorable growing conditions. The noble broadleaved trees naturally growing in Finland are:
The ranges of oak, ash, and European white elm in particular are restricted to a narrow area in southern Finland.
The northern limits of the natural distribution areas of all these species run through Finland.
Global warming is likely to expand the suitable conditions for these species further north.
Currently, damage caused by moose is the greatest obstacle to increasing the cultivation of most of these species, and for example, the planting costs of pedunculate oak are several times higher than those of pine or spruce. Some species also face challenges due to limited availability of planting material.
In addition, uncertainty about the suitability of the timber for the wood-processing industry acts as a barrier to wider cultivation. Although several of these species can produce high-quality timber, modern Finnish wood industry makes little use of it today.
Management and Production of Noble Broadleaved Trees
The cultivation of noble broadleaved trees requires special attention and active forest management if the goal is to produce high-quality timber. Noble trees represent an ecologically diverse group, and therefore there are no universally applicable guidelines for their management. Common challenges include damage caused by mammals during the seedling stage and the trees’ tendency to produce low-quality wood if development is not guided through proper silvicultural practices.
In Finland, noble broadleaved trees grow at the limits of their natural range, which makes them susceptible to extreme weather conditions. For this reason, site selection is especially important. In addition, the markets for noble broadleaved timber are challenging: unlike for more common tree species, logistics and processing chains for noble timber have not been well developed, making profitable cultivation difficult. Consequently, supply and demand are often hard to match. The motivation of forest owners to grow noble broadleaved trees is often driven more by an interest in experimentation than by economic gain. However, when the right buyer is found, noble timber can fetch a good price.
The prices of noble broadleaved seedlings are generally quite high, and they often require dense planting and protection against mammal damage, which increases establishment costs. Noble trees are mainly light-demanding species. However, abundant light and vigorous growth can lead to a decline in stem quality due to increased branching and curvature. To prevent this, young stands should be kept dense. As the trees grow older, thinning is not needed to ensure sufficient light and crown vitality. The most valuable wood comes from knot-free butt logs, so timely pruning is important. In some species, natural self-pruning can be promoted through vertical stand density management.
Noble broadleaved trees can be cultivated either as pure stands or in mixed forests together with other tree species. Mixed cultivation is often more cost-effective, but producing high-quality noble timber requires forest management based on the needs of noble broadleaved trees, which may conflict with the requirements of other species.
Noble Broadleaved Trees: Pedunculate Oak
In Finland, oaks occur naturally only in the southern parts of Uusimaa and Southwest Finland, where they can locally form their own stands. However, planted oaks can survive considerably farther north. The northern limit of oak growth is largely determined by its frost tolerance, which is around –40 °C. Oaks have therefore been widely planted, for example in cultural environments and gardens, but to a lesser extent also as small forest stands beyond their natural range. Despite its rarity, the oak holds a significant place in Finnish folklore and mythology, reflecting its deep cultural importance.
Oak thrives best on fertile soils, such as groves and rich forests. The species is long-lived and begins to produce acorns only at 20–30 years of age. Although oak is a light-demanding species, young trees tolerate shading quite well, but their need for light increases as they grow. Oaks naturally form side branches and tend to fork easily. Especially as they age, oaks provide habitats for numerous organisms and thus promote biodiversity.
From a forestry perspective, the species’ tendency to branch and fork is undesirable. In addition, the susceptibility of seedlings to damage makes stand establishment difficult. During the seedling stage, oaks are especially vulnerable to damage caused by mammals, particularly voles, deer, and hares. Establishing a high-quality oak stand requires dense planting, as early mortality can be high. However, this can make oak cultivation expensive, since a large proportion of trees must be removed through thinning before they reach economic value. For this reason, a recommended method is mixed cultivation, where oaks are regenerated in small groups interspersed with other tree species. Young oak stands must be kept dense to ensure straight, knot-free stems. The stand should be thinned frequently and carefully. Strong thinnings too early can lead to excessive crown development and forking, which reduces timber quality.
Site information
PUN90
61.80955 ja 29.31965
Altitude above sea level 92m
The oak stand was planted in 1927 (seedlings 2 years old):
|
Year |
Trees remaining |
Avg height |
Avg diameter |
|---|---|---|---|
|
2009 |
152 (163 trees/ha) |
22,7 m |
31,0 cm |
|
2025 (trees 100 years old) |
133 (141 trees/ha) |
23,6 m |
23,6 cm |
