Biodiversity in nature encompasses not only the abundance of different species but also the diversity within each animal and plant species. Individuals vary due to environmental factors and their genetic makeup. The diversity within a species resulting from different genes is called genetic diversity.
Genetic diversity is crucial for a species because the environment it has adapted to undergoes changes. Previous top performers may not necessarily be the most competitive in a new situation. However, when a population, such as trees in a forest stand, contains a variety of genes and individuals, new, better-adapted winners can be found among them. This ensures the future of the species or the forest stand. In long-lived forest trees, this process is slow, while environmental changes, currently most notably climate change, may occur rapidly.
In Finland, the genetic diversity of forest trees is protected through a dedicated program. Generally, the genetic diversity of common tree species (pine, spruce, birch) is preserved in their original habitats, in so-called gene reserve forests. Gene reserve forests represent the natural genetic makeup of each habitat, and they are managed to include all stages of forest development. During forest regeneration, it's crucial to ensure abundant seedling establishment.
However, gene reserve forests are never regenerated with genetically improved or introduced planting material. For rare tree species, such as noble broadleaves, genetic diversity is specifically conserved in established gene bank collections, where material from several natural stands of the same tree species is brought together. This creates a new stand that is genetically more diverse than very small natural occurrences while still being adapted to the Finnish climate.
