Elm in the Highlands: current status and potential management responses to Dutch elm disease Euan Bowditch & Elspeth Macdonald (University of the Highlands and Islands, Inverness College) 1 | P a g e Table of Contents List of Figures .................................................................................................................................. iii List of Tables .................................................................................................................................... iv Executive Summary ........................................................................................................................ 1 1. Introduction ................................................................................................................................. 4 2. Background ................................................................................................................................... 4 3.1 Spatial extent of elm in Scotland .................................................................................................. 7 3.2 Spatial extent of Elm species in the Highlands and Islands ............................................. 11 3.3 Elm survey results and analysis ................................................................................................. 20 3.3.1 Dutch elm disease areas ........................................................................................................ 22 3.3.3 Possible vectors and routes for the spread of DED ..................................................... 26 4. Habitat value of wych elm ..................................................................................................... 31 4.1 Birds ..................................................................................................................................................... 31 4.2 Lichens, and bryophytes ............................................................................................................ 31 4.3 Insects ................................................................................................................................................. 33 5. Production and commercial aspects .................................................................................. 34 5.1 Nurseries and stock ......................................................................................................................... 34 5.1.1 Seeds .............................................................................................................................................. 34 5.1.2 Nursery production ................................................................................................................. 35 5.2 Timber and milling .......................................................................................................................... 36 6. Landscape and social aspects ............................................................................................... 40 6.1 Landscape value ............................................................................................................................. 40 6.2 Perception of elm in the landscape ..................................................................................... 42 6.3 Economic value of elm as a species...................................................................................... 45 i | P a g e 7. Future prospects and recommendations ......................................................................... 48 7.1 Main findings ...................................................................................................................................... 49 7.2 Recommendations ........................................................................................................................... 51 7.2.1 Planting and restoration strategies ................................................................................... 52 7.3 DED practice and control .............................................................................................................. 57 7.3.1 Management and control methods in the Highlands and Islands ......................... 59 7.4 Management options and action plans .................................................................................... 59 7.4.1 Proposed elm refuges ............................................................................................................. 60 7.4.2 Management Actions ............................................................................................................... 66 7.5 Further research ............................................................................................................................... 72 8. Summary – Elm futures .......................................................................................................... 74 References ....................................................................................................................................... 76 Appendix A – Example of Elm survey ..................................................................................... 86 Appendix B – Example of Sawmill survey ............................................................................. 90 Appendix C – List of respondents and consultees .............................................................. 93 Appendix D – Complete tables of Highland Wards and Refuges planting areas ..... 94 Appendix E – Elm hybrids and varieties that show resistance to DED ....................... 96 Appendix F – Financial implications tables ......................................................................... 98 ii | P a g e List of Figures Figure 1 – Map showing the extent of elm over the Forestry Commission Conservancy areas .................................................................................................................................................................... 8 Figure 2 – Structure of elm tree population in Scotland (percentage) .................................. 11 Figure 3 – Map showing the extent of elm woodland areas over the Highland Wards ... 12 Figure 4 – Area of elm species in Highlands and Islands electoral wards ............................ 13 Figure 5 – Areas of woodland in the Highlands and Islands electoral wards with 25%+ elm canopy cover (in areas with elm species as a component) ................................................. 14 Figure 6 – Areas of woodland in the Highlands and Islands electoral wards with 50%+ elm canopy cover (in areas with elm species as a component) ................................................. 14 Figure 7 – Map showing the density of elm canopy cover in woodlands containing elm, across the Highlands and Islands area ................................................................................................ 15 Figure 8 – Map of elm areas and density around the Cromarty Firth .................................... 16 Figure 9 – Successional structure of elm species in the Highlands and Islands (percentage) (NWSS, 2014) ..................................................................................................................... 17 Figure 10 – Levels of herbivore browsing pressure in elm woodlands in the Highlands and Islands (percentage) (NWSS, 2014) ............................................................................................. 18 Figure 11 – Range of habitat types associated with elm species (NWSS, 2014) ................ 19 Figure 12 – Main primary or secondary species of mixed elm woodland in the Highlands (NWSS) ....................................................................................................................................... 19 Figure 13 – Species that the survey respondents most commonly associated with wych elm in the Highlands ................................................................................................................................... 21 Figure 14 – Areas of elm trees identified by survey respondents ........................................... 23 Figure 15 – Examples of elm trees in the Highland region that have recently been infected by DED ............................................................................................................................................ 24 Figure 16 – Healthy elm around Loch Alsh ...................................................................................... 25 Figure 17 – Known and potential vectors of DED through the landscape............................ 26 Figure 18 – Climatic zone baseline for broadleaves ..................................................................... 28 Figure 19 – W8 suitability climate map for the Highlands (ESC, 2016) ................................ 29 Figure 20 – Recorded occurrences of orange-fruited elm-lichen (Calopplaca luteoalba) over the last 60 years, illustrating the decline in elm specialist lichens (Data courtesy of iii | P a g e the NBN Gateway with thanks to all the data contributors. https://data.nbn.org.uk/Taxa/NBNSYS0000020545/Grid_Map The NBN and its data contributors bear no responsibility for the further analysis or interpretation of this material, data and/or information.) ..................................................................................................... 32 Figure 21 – Forestry Commission native seed zones for Scotland .......................................... 35 Figure 22 – Perceived use of elm timber ..........................................................................................