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Brian g. crane 2013 INITIAL RESULTS FROM A LONG TERM STUDY OF THE EFFECTS OF ROOT DAMAGE ON STREET TREES European Conference of Arboriculture Planning.

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Presentation on theme: "Brian g. crane 2013 INITIAL RESULTS FROM A LONG TERM STUDY OF THE EFFECTS OF ROOT DAMAGE ON STREET TREES European Conference of Arboriculture Planning."— Presentation transcript:

1 brian g. crane 2013 INITIAL RESULTS FROM A LONG TERM STUDY OF THE EFFECTS OF ROOT DAMAGE ON STREET TREES European Conference of Arboriculture Planning the green city: relationships between trees and infrastructures Turin 26th-28th May 2014 brian g. crane 2014

2 2 A THOUGHT A layman, a mathematician and a scientist are driving through Wales. They see a black sheep: ‘Look’, says the layman, ‘the sheep in Wales are black’ ‘No’, says the mathematician, ‘in Wales there is one black sheep’ ‘Not so’, says the scientist ‘in Wales, there is a sheep – we know half of it is black’

3 THE ARBORICULTURIST’S BIG QUESTION But what’s happening here? We know a lot about how the aerial parts function – because we can see them working and measure what’s happening brian g. crane 2014

4 4 HEALTH WARNING!!! The data in this presentation has been checked, but further validation is required before finalisation and publication. Due to the large database, any amendments and the effect they have on figures is likely to be limited brian g. crane 2014

5 5 Project Outline and Timings 1994Record root damage to street trees in the London Borough of Havering 2000/1 Follow-up visit collecting limited data – 1994/2001 data transferred to MS Excel spreadsheet 2013Full re-survey of aerial parts. Analysis of data brian g. crane 2014

6 6 IMPORTANT BECAUSE: Thought to be the largest assessment of its kind ever carried out: Over the longest period of time Trees are mature Subject to urban pressures Large study population brian g. crane 2014

7 7 FIGURES 1994 – 1,168 trees assessed. 2001 – re-survey – results overtaken by 2013 survey 2013 - 1,061 trees assessed. Period of Time: early 1994 to June/July 2013. brian g. crane 2014 Approximately 100 trees removed. Cable installation company paid £250,000 GBP compensation.....and agreed planting of 3 trees for every one removed

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9 9 SOIL !!!! Yum!!!! brian g. crane 2014

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11 11 LONDON BOROUGH OF HAVERING Outer London Borough Main period of development in surveyed areas – inter-war Main areas surveyed: Romford Hornchurch Harold Hill Elm Park brian g. crane 2014

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14 14 brian g. crane 2014 Rooting depth ‘...from numerous studies involving comprehensive root excavations the indication is that typically as much as 90% of the tree root length occurs in the upper metre of soil ’. (Roberts, R., Jackson, N. and Smith, M. 2006 Tree Roots in the Built Environment) ‘Overall temperate broadleaved trees have 82% of their roots in the upper 50 centimetres of soil...’ (Jackson, R.B., Canadell, J., Ehleringer, J.R., Mooney H.A., Sala, O.E. and Schultz, E.D. 1996. A global analysis of root distribution for terrestrial biomes. Oecologica, 389-411).

15 15 Dated: 2003 brian g. crane 2014


17 17 Crown condition. Almost all the crowns of existing trees were in good condition. This was assessed on leaf cover, leaf size and extension growth. Almost all the trees had been managed by heavy crown reduction on a regular basis. Heavy crown reduction was assessed as existing when a tree showed reduction back to cuts of 150 millimetres or more. Assessment of suitability for follow-up survey with ground- searching radar – if woody plants near enough for roots to confuse radar, site not selected. In 46% of eligible sites the street tree was the only significant vegetation. brian g. crane 2014 Applies to both tree AND each root

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19 Remarks 1994Root diameter Distance from trunk DepthRoot Severed Y/N Root matrix value Total weighting Phone pole adjacent-wires in crown. Adjacent to cross over - Large surface buttress roots. 1821015Y22 Adjacent to cross over - Water pipe between tree street lamp adjacent and Encom trench. 3225015Y22 7519020Y611 1619020Y2 1919015Y2 819015Y1 820020Y0 42005N0 Link ID RoadLocationDate of Inspection SpeciesHeight Trunk diamete r at 1.5 metres Crown radius Age 1Alan GardensO/S 6/818/10/1994Acer pseudoplatan us 10 446M 2Alan GardensO/S 4/218/10/1994Platanus x hispanica 10 806M 3Alan GardensFlank of No 118/10/1994Platanus x hispanica 12 558M 3 3 3 3 3 19 brian g. crane 2014 ROOT DAMAGE MATRIX Complete spreadsheet 4414 lines, 67 columns

20 Root diameter Distance from trunk DepthRoot Severed Y/N Root matrix value Total weighting Weighting class 1821015Y22VL 3225015Y22VL 7519020Y611H 1619020Y2 1919015Y2 819015Y1 820020Y0 42005N0 brian g. crane 2013 20 ROOT DAMAGE MATRIX Root size (diameter at cut end) Overall severed root diameter or numbers Weighting Total weighting Weighting class <1 metres from trunk 1 to 1.5 metres from trunk >1.5 metres from trunk <9 millimetres Less than 100 millimetres in total * 1111, 2Very low <9 millimetres Between 100 and 500 millimetres in total* 2443 to 5Low <9 millimetres Over 500 millimetres in total* 4216 to 7Moderate 10 to 24 millimetres Per root322 8 to 11High 25 to 49 millimetres Per root64212 - 21Very high 50 to 79 millimetres Per root1086>21 Extremely high 80 to 99 millimetres Per root12108  C1 if roots present  C2 if no roots

21 21 DATA HANDLING  Remove invalid entries (unlocated or misidentified trees, data entries which appeared to be incomplete)  Develop single-line entry for each tree using root damage matrix  Merge spreadsheets  Check continuity of entries  Interrogate data  Sample re-check data with GIS entries brian g. crane 2014 Tilia x europaea planted in mid 1800s. Roots cut down to about 1 metre depth in 1970s. Tree still growing with good vigour

22 22 brian g. crane 2014 Tilia Acer SPECIES BREAKDOWN

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28 28 FACTORS AFFECTING STREET TREE LOSSES IN URBAN AREAS  Changing fashions (e.g. replacement of larger species with smaller)  Disease outbreaks – particularly common in monocultures)  Pressure from individual householders  Subsidence claims  Removal of declining stock (overmaturity)  Cost of management  Highway and utility works  Development brian g. crane 2014 Mature Acer pseudoplatanus. Roots cut down to about 1 metre depth for theatre car-parking in 1970s. Tree still growing with good vigour

29 29 ClassNumberPercentage of total Trees remaining69665.6 Missing trees (adjusted) 28426.7 Vehicle crossovers777.3 Abiotic removals40.4 Overall results – Missing trees have been adjusted to show effects of vehicle crossovers and ‘abiotic’ removals brian g. crane 2014

30 30 ClassNo% Small trees original population117 Missing small trees6555.6 Large trees original population935 Missing large trees28630.1 Differences in losses between smaller, short-lived and larger, longer-lived genera brian g. crane 2014

31 31 TO SHOW AVERAGE d.b.h. INCREASE BETWEEN 1994 AND 2013 d.b.h. centimetres brian g. crane 2014

32 32 ClassNumberPercentage Control trees363 Control trees missing10222.9 Control trees crossovers19 Non-control trees698 Non-control trees missing28632.2 Non-control trees crossovers61 Control/non-control tree survival – adjusted by subtracting ‘crossovers’ from ‘missing’ totals. brian g. crane 2014

33 33 To show losses expressed as % age of each damage grouping Percentage brian g. crane 2014 Average %age loss over all damage ranges %age loss - control trees

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35 35 Extremely heavy damage Very heavy damage Heavy damage Moderate damage Light damage brian g. crane 2014

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37 37 WHERE NOW?  Try to establish reasons for tree removals in localised areas using Freedom of Information Act  Re-check data – interrogate using Access database – increase parameters  Prepare, peer-review and publish full paper  Examine funding for ground- searching radar analysis of selected sites – first attempt to secure funding was unsuccessful brian g. crane 2014

38 38 My sincere thanks to: David Cutler Professor of Plant Science and Research Fellow, Royal Botanic Gardens, Kew Francesco Ferrini Professore di Arboricoltura urbana e di Parchi e Giardini, Dipartimento di Ortoflorofrutticoltura - Università di Firenze, Italy Edward F Gilman Professor, University of Florida, Environmental Horticulture Dept Tom Smiley Arboricultural Researcher, Bartlett Tree Research Lab, Charlotte NC Gary Watson Senior Research Scientist Morton Arboretum Adjunct Professor, University of Illinois Jeremy Barrell Registered Consultant, Arboricultural Association, Chartered Arboriculturist, UK Dave Shandley Mobile GIS Services, UK brian g. crane 2014

39 39 THE END Thank you for your attention brian g. crane 2014

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