A Comparison of Urban Tree Populations within Four UK Towns and Cities

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1 A Comparison of Urban Tree Populations within Four UK Towns and Cities Trees, People and the Built Environment 2014 Heather Rumble, Kenton Rogers, Kieron Doick and Tony Hutchings

2 The problem - Urbanisation 80% live in cities This will increase Environmental problems Pollution Flooding Loss of wildlife Urban heat island Iain Buchanan,

3 The solution Trees? Provide numerous ecosystem services Carbon capture Filter airborne pollutants Alleviate flooding Provide habitat Cool surrounding areas Increase mental wellbeing Aesthetic appreciation Gaeser,

4 How many trees are in the urban environment? What ecosystem services do they provide? What is driving urban tree populations? What challenges do urban trees face? Eforfateu,

5 i-tree Developed by the USDA Used worldwide Field based method to assess the ecosystem services provided by trees 5

6 How many trees are in the urban environment? What ecosystem services do they provide? What is driving urban tree populations? What challenges do urban trees face? Eforfateu,

7 How many trees are in the urban environment? What ecosystem services do they provide? What is driving urban tree populations? What challenges do urban trees face? Eforfateu,

8 What is driving urban tree populations? Species Size Land use types What challenges do urban trees face? Pests and diseases Diversity Climate change Drought Waterlogging Rebecca Beeston,

9 Four i-tree surveys plots sampled Recorded land characteristics Recorded tree characteristics Species Height Canopy width DBH Health 9

10 Species composition top ten species All four study areas Acer psuedoplatanus Fraxinus excelsior Three study areas Cupressocyparis leylandii Crataegus monogyna Betula pendula Ptelea,

11 Dim 2 (29.21%) Comparing urban tree populations Individuals factor map (PCA) Glasgow Torbay Wrexham Edinburgh Dim 1 (46.29%) 11

12 Sycamore 12% Holly, common 11% Cherry (genus) 4% Other species 35% Wych elm 4% Scots pine 4% Edinburgh Rowan, common 5% Beech, common 5% Leyland cypress 6% Ash, common 6% Silver birch 8% English oak 4% Goat willow 4% Hazel, common 4% Other species 31% Willow (genus) 4% Wild cherry 4% Wrexham Sycamore 16% Hawthorn, common 12% Ash, common 5% Silver birch 11% Leyland cypress 5% 12

13 Frequency/% Comparing urban tree populations Top ten species frequencies Other Most common species Wrexham Glasgow Torbay Edinburgh 13

14 Park Agriculture Other Institutional Vacant Cemetery Residential Golf course Transport Commercial Utility Multi-family Wetland Frequency/% Comparing urban tree populations Frequency by land use type Land use type Edinburgh Glasgow Torbay Wrexham 14

15 Frequency/% Comparing urban tree populations Size distributions < Size class Edinburgh Glasgow Torbay Wrexham "Ideal" 16

16 Diversity - The 10:20:30 rule No species more than 10%: Edinburgh Acer psuedoplatanus, 12% Ilex aquifolium, 11% Torbay Cupressocyparis leylandii, 16% Fraxinus excelsior, 13% Glasgow Fraxinus excelsior, 13% Crataegus monogyna, 11% Wrexham Acer psuedoplatanus, 17% Crataegus monogyna, 13% Betula pendula, 12% 18

17 Diversity - The 10:20:30 rule No genus more than 20%: None No family more than 30%: None 19

18 Edinburgh Private or public Glasgow Public 27% Private 64% Public 42% Private 56% Either 9% Either 2% Torbay Wrexham Public 63% Public 70% Either 17% Private 20% Private 27% Either 3% 20

19 TOTAL Residential Park Commercial Institutional Agriculture Vacant Golf course Multi-family Transport Cemetery Other Utility Wetland Shannon Wiener diversity Comparing urban tree populations Diversity Land use type Edinburgh Glasgow Torbay Wrexham 21

20 Frequency/% Comparing urban tree populations Response to drought >2, 3 >3, 4 >4, 5 No index value Title Wrexham Glasgow Torbay Edinburgh 22

21 Response to waterlogging, Glasgow Data not available 18% >4, 5 4% 2 48% >3, 4 18% >2, 3 12% 23

22 Conclusions i-tree i-tree data can be used beyond ecosystem services i-tree provides a standardised data collection method UK tree populations Self-seeding pioneers most common Abundances similar to Trees in Towns II 24

23 Conclusions Diversity Maintained land uses generally more diverse Some species exceeded 10% abundance Genus and family limits were not exceeded Tree officers may have data missing when assessing this Resilience to climate change Torbay had lots of drought tolerant species Glasgow had few waterlogging tolerant species 25

24 Acknowledgements Edinburgh City Council Glasgow City Council Wrexham County Borough Council Torbay Borough Council NRW FC Scotland i-tree, USDA Moray Simpson and Elton Watson of WCBC Paul Taylor and Phil Handley of FR The Woodland Trust CEH SEPA Moray Simpson, 2013 The i-tree field teams and the kind residents who let us access their property 26