Forest Genetic Resources

The Centre for Genetic Resources, the Netherlands (CGN) advises Staatsbosbeheer, the Dutch government organisation for forestry and nature reserves, on the management of the national genebank for trees and shrubs (ex situ conservation).

This is one of the ways that CGN stimulates the conservation and sustainable use of the genetic diversity of indigenous tree and shrub species. This is important as trees and shrubs can only survive climate change or new diseases if they can draw on significant genetic diversity.

The genetic diversity of trees and shrubs forms the basis for sustainable forestry and nature management. It impacts wood production and plays an important role in resistance to pests and diseases, and the adaptation to climate change.

This is why it is crucial that genetic resources of trees and shrubs are conserved, maintained and used in a sustainable way. It is estimated that less than 5 per cent of the original Dutch vegetation remains. Autochthonous gene material is essential for the quality of ecosystems.

Searching and requesting material

Staatsbosbeheer, the Dutch government organisation for forestry and nature reserves, manages the genebank for indigenous trees and shrubs and is responsible for issuing seeds and cuttings. The Centre for Genetic Resources, the Netherlands (CGN) advises Staatsbosbeheer and provides the genebank with scientific support.

The field collection

The gene bank comprises a field collection that was built-up in the Roggebotzand forest area in the Flevopolder since 2002 and is managed by Staatsbosbeheer. The field collection features over 50 indigenous species of trees and shrubs and 4790 accessions that originally grew in the Netherlands and of which the indigenous gene resources are at risk. The genebank brings the accessions together in large populations from which seed can be harvested. As well as conserving diversity, the gene bank also facilitates use by providing seeds and plant material for new nature. Among others, the gene bank includes hawthorn, white elm, black poplar, small-leaved lime and gooseberry.

The National List of Varieties and Provenances of Trees is a tool for the development of forests, landscaping and public green spaces. It comprises a comprehensive and up-to-date list of recommended provenances and varieties to be planted in the Netherlands. The list contains a plethora of information for terrain managers, consultancy firms, landscape contractors and anyone involved in the planting of new trees and shrubs.

The most recent version is available on the Dutch website indicated below.

List for provenance choice

It is important to choose the right plant material in the right place as the growth of trees and shrubs is a long-term process. Using the right provenance is crucial as this will indicate in which place (stand) the seeds were harvested and determine the genetic quality of the plant material.

CGN resource data

The National List of Varieties and Provenances of Trees falls under the responsibility of the Board for Plant Varieties. Scientists from the Centre for Genetic Resources, the Netherlands (CGN) constantly update the list. In addition to seed sources selected for growth capacity and wood quality, there is a specific focus on indigenous trees and shrubs in order to maintain the unique biodiversity of the Netherlands.

The biodiversity of nature and landscapes has been on the decline for years, making it vital to conserve indigenous gene resources of those trees and shrubs which are still available. The conservation of genetic diversity is crucial for the resilience of forests, adaptation to climate change and variation in the landscape.

A provenance trial full of wild cherries is located in the Flevopolder. Here, the Centre for Genetic Resources, the Netherlands (CGN) tests the adaptability of seed sources from the Netherlands, Belgium, Germany, France and UK to Dutch conditions as well as their growth capacity, wood quality and health. Wild cherry is one of the many tree species of which CGN collects information in these tests. Another example involves an international beech test. CGN performs this research for the National List of Varieties and Provenances of Trees to advise users in choosing forest reproductive material.

• Genetic characterisation with SNPs
  CGN uses DNA research to analyse the genetic diversity in the collections. SNP genotyping is deployed to further characterise genetic diversity in the genebank collections and optimise the collections. One of the issues studied for the wild apple collection is whether hybrids exist with the cultivated apple.

In situ conservation

CGN supports and stimulates both in situ (original location) and ex situ (genebank) conservation of the genetic diversity of indigenous trees and shrubs. The conservation of genetic diversity is coordinated within a European framework (EUFORGEN).

The EUFGIS database provides information on the ‘gene conservation units’ assigned by the countries involved. These locations are where important populations of (indigenous) trees and shrubs grow and where they grew originally.

Ex situ conservation: the genebank

CGN also scientifically supports the gene bank (ex situ conservation) which contains over 50 indigenous species of trees and shrubs and 4790 accessions that originally grow in the Netherlands and of which the indigenous gene resources are at risk. Among others, the gene bank includes hawthorn, white elm, black poplar, small-leaved lime, gooseberry and wild apple. We support Staatsbosbeheer, the Dutch government organisation for forestry and nature reserves, in the build-up, maintenance and optimisation of the collections and further expansion with additional accessions. DNA markers are used to characterise the genetic diversity and relations between materials in order to advise Staatsbosbeheer on the possible separation or combination of populations and individuals.

• ‘New’ tree species
  In addition to well-known forest tree species, interesting ‘new’ species are available for the development of future forests such as the walnut and Turkish hazel. Although they may be of interest for use in the Netherlands for their ability to respond to climate change, there is an increased risk of frost damage. To assess this, CGN has two field tests with nut species, including their hybrids.

Ash dieback

The common ash is a valuable tree species which has been suffering since 2010 from ash dieback (Hymenoscyphus fraxineus), an invasive fungus from Asia. Only a fraction of all ash trees is resistant to this disease. CGN collected 155 trees from the genebank and forests across the Netherlands to study for possible resistance to ash dieback. The trees were artificially infected with the fungus in order to identify trees that can replace highly susceptible ash trees.