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The Birch and Alder Improvement Programme

17 May 2020
Type Media Article

The development of birch as a commercial forestry tree species supports government policy in the desire to increase diversity in Irish forestry

Oliver Sheridan, forestry researcher with Teagasc Ashtown, discusses the commercial development of Birch in Ireland on a recent episode of The Research Field.

Birch is one of the most common woodland trees in Ireland, but has long been regarded as a timber species of minor importance due to its poor stem quality and poor survival and growth rates; and, as a result, birch was not included on the recommended species list for afforestation grants. However, there is a growing interest in native broadleaf species such as downy birch (Betula pubescens (Ehrh.)) and silver birch (Betula pendula (Roth)) and experience from abroad has indicated that birch had potential for improvement. The development of birch as a commercial forestry tree species supports government policy in the desire to increase diversity in Irish forestry. The physiology of birch means that it can be planted on land that would not be suitable for other broadleaf species. Birch has a short rotation period, about 40-50 years, in comparison to other native broadleaves, such as oak and ash.

The birch improvement programme was initiated back in the late 1990s and the approach to develop sources of improved planting stock has been:

  • Locating the best examples of mature birch trees (plus trees) in Ireland
  • Cloning the plus-trees (by grafting)
  • Establishing gene banks to preserve the genotypes
  • Establishing field trials to assess the value of the trees as parents
  • Establishing seed orchards

The overall objective of the research is the development of a sustainable supply of improved, adapted, healthy seed and plant material of birch and alder within the framework of the EU Forest Reproductive Material (FRM) regulations.

Teagasc Birch Seed Orchard

In 2012, the Teagasc indoor seed orchard was established with 90 plus tree selections, (mainly downy birch) based on data collected after 10 growing seasons from the birch field trials. The Teagasc indoor seed orchard is located at the Teagasc Research Centre, Ashtown, Dublin 15.

In 2013, the indoor seed orchard achieved the improved designation “qualified” under an EU directive on the marketing of Forest Reproductive Material (FRM).

Overview of seed categories of Forest Reproductive Material

Quality

Name

Description

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Tested

Tested seed derives from the selection of individual trees or stands which have been evaluated for genetic quality or, in comparison to accepted standards, have been shown to be superior.

Qualified

Qualified seed derives from the selection of superior individual trees. No testing has been carried out.

Selected

Selected seed is collected from stands showing superior characteristics: e.g. better form, growth rate, health.

Source identified

Source identified seed comes from general or specific locations. No specific superior qualities recognised.

The Teagasc Birch and Alder Improvement Programme is now working towards achieving the highest possible category under this directive, i.e., “tested”.

To progress this stage of the programme from “qualified” to “tested” category, two field trials were established in 2017 with birch plant material raised from the Teagasc “qualified” indoor seed orchard.

In 2015, the research reached a stage in the Birch Improvement Programme where there was plant material suitable for commercial exploitation. None So Hardy Nurseries (Teagasc commercial partner), with the support from the Department of Agriculture, Food and the Marine (DAFM) under the Forest Genetic Resources Reproductive Material: Seed Stand and Seed Orchard Scheme, constructed a new purpose built polytunnel to house the improved birch plant material supplied to them by Teagasc.

The first improved birch planting stock for commercial planting was available from None So Hardy Nurseries for the 2016/2017 planting season.

Because of this long-term investment in forestry research, birch is now a grant-aided species. It can be planted under Grant and Premium Category (GPC) 8 as a pure timber crop if “qualified” or “selected” seed is used.

Gene Bank

A gene bank was established at Teagasc, Oak Park, with the full collection of birch and alder plus tree clones with room to add new selections as they become available.