Forest Genetic Resources

Genetic resources of a forest include biological matter of forest trees (populations, groups of trees, individual trees and their parts) containing actually or potentially valuable (in the ecological, breeding, economic, or some other sense) genetic information. Genetic resources of a forest constitute a national asset of each country, warranting sustainability of biological resources and full existence and sustainability of various forms of life, including the human one. Protection, promotion, and rational use of these resources represent some of the most important components of the modern sustainable forestry and environment protection.

The value of genetic resources is closely linked to genetic diversity – the larger the diversity, the more valuable the genetic resources. Genetic diversity is described in terms of genetic variability within and between populations. Along the species diversity and ecosystems diversity, the genetic diversity represents a crucial component of a biodiversity. In the face of rapid changes in climate and environment taking place today, survival, reproduction, and evolution of each species is largely dependent on genetic diversity. Therefore, effective preservation of genetic diversity is crucial for success of preservation of the whole of biodiversity.

The purpose of preservation of forest trees genetic resources in the face of changes in climate and environment of today and tomorrow is to preserve evolutionary potential of each species. This requires preservation of genetic variety and creation of favorable conditions for survival, increasing adaptation, and restoration of each population of genetic resources. The basis of sustainable preservation of genetic resources is a network of special in situ (arboretum preserves) and ex situ (descendants of trail strains) populations. Using special dynamic management, sustainability of species in all stages of ontogenesis, as well as full and timely reproduction and development of population is ensured.

In Lithuania creation of the system of objects designed for preservation, research, breeding, and seed-growing of genetic resources of a forest started 40 years ago. Currently genetic resources are preserved in their natural habitats (in situ) as well as in new growing environments or by storing their reproductive parts in storage facilities (ex situ). The basis of the new system of preservation and breeding of genetic resources of a forest is constituted by a network of small in situ (preserved) subpopulations and ex situ (descendants of trial strains) subpopulations, selected and developed according to principles of the Multi-Population Breeding System (MPBS). The populations are growing under different conditions in various natural regions of Lithuanian forests. The populations are dynamically managed in order to ensure sustainability, full reproduction, and development in different directions. To increase efficiency and to reduce costs, preservation and breeding of genetic resources is being conducted concurrently, under a single Forest Genetics and Breeding Development Program.

Preservation in situ:

  1. Forest genetic preserves are defined forest territories, designated for long-term preservation of valuable populations or parts of populations of forest trees. Preserved are created in populations characteristic of ecologic regions of Lithuania or in populations having valuable breeding characteristics. Populations for preserves are selected on the basis of qualification criteria pertaining to genetic diversity, quality, and productivity. When forming preserves, priority is given to risk zones and populations of particular importance. Preserves are managed with a view on creating age diversity within a population of trees and on promotion of natural reproduction of the population.

  2. Seed populations are populations of high-productivity and high-quality trees, which are designated for production of seeds and preservation of genetic resources. Seed populations of trees are divided into two categories: a) permanent populations of trees, which are grown till natural maturity and in which seeds fall down and are collected from under the trees (oak, ash, maple, linden, elm, hornbeam), and b) regenerated populations of trees – mature populations of trees are cut down for collection of seeds (in seed years) and regenerated using the same seeds (because it is inefficient to collect seeds from growing trees and it is impossible to collect seeds from the ground) (pine, spruce, larch, asp, black alder).

  3. Individual trees – these are select (plus) trees, valuable from both ecological and economic points of view, as well as unique trees or trees representative of populations. The trees are selected on the basis of the set qualification requirements.

Preservation ex situ:

  1. Clone collections (collections, archives) are systematized populations of selected, vegetatively reproduced genotypes, which are valuable from both ecological and economic points of view.

  2. Forest seed plantations of closed are populations of a set number of vegetatively reproduced genotypes, which have been arranged (mixed) in a certain way in order to grow seeds valuable from the point of view of breeding. These plantations also perform functions of preservation of genetic resources.

  3. Trial populations of descendant families are collections of families designed for preservation of genetic resources and testing of populations and plus trees in terms of growing of their descendant families in other habitats.

  4. Samples of seeds of populations, their parts, or individual trees stored in the Genes Bank.