Wych Elm Project

Natural Resources Wales (NRW) has commissioned Treborth Botanic Garden (TBG) to propagate material from mature wych elms on and adjacent to the Allt y Benglog National Nature Reserve (NNR) in Meirionydd.  The mature elms support a rare lichen: Biatoridium monasteriense, which is currently the only known site for the species in Wales.

The purpose of the project is to try to ensure that a suitable substrate continues to be available within the NNR for the lichen to colonise in the future.  The ‘mother tree’ for the lichen blew down several years ago and has been righted and continues to support the lichen, but is vulnerable in the medium to long term.  Two further trees downstream have been identified as supporting the lichen. Only two other mature wych elms are known to exist within the site, but they do not currently seem to support specimens of B. monasteriense.

Wych ElmTBG proposes to propagate material from the mature elms using several appropriate techniques:

  • Hardwood cuttings - to be collected in winter
  • Softwood cuttings - to be collected in summer
  • Air layering - summer
  • Seed - seed to be collected when ripe (probably May)

The preferred techniques are cuttings / layering as these will produce trees genetically identical to the parent trees, increasing the likelihood of producing a suitable substrate for the lichen.