Abstract
Highway embankments and cutting slopes in the United Kingdom, particularly in the South East of England, are often constructed of or within stiff over-consolidated clays. These clays are prone to softening with time leading to shallow slope failures and costly repairs. Reinforcement by natural vegetation is potentially a cost-effective method of stabilising these types of slopes over the medium–long term. However, there is a lack of information on how natural vegetation reinforces and stabilises clay slopes. To investigate this problem, the potential reinforcement of selected oak (Quercus robur L.) and hawthorn (Crataegus monogyna Jacq.) roots was assessed by conducting in situ root pull-out experiments on a London Clay cutting in south-east England. Pull-out tests were carried out using specifically designed clamps and either a hand pull system with a spring balance and manual recording of force for oak roots or a jacking system with electronic data logging of applied force and displacement for hawthorn roots. Oak roots had a mean pull-out resistance of 7 MPa and that of hawthorn roots was 8 MPa. The electronic data logging of applied force (pull-out resistance) and displacement of the hawthorn roots provided additional data on the failure of branched roots which could be correlated with variations in root morphology. The failure of the roots can be categorised into three modes: Type A: single root failure with rapid rise in pull-out resistance until failure occurs; Type B: double peak failure of a forked or branched root and Type C: stepped failure with multiple branches failing successively. The different types of root–soil bonds are described in relation to root anchorage and soil stability.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Achim A, Nicoll B, Mochan S and Gardiner B 2003 Wind stability of trees on slopes. In Proceedings of the International Conference ‘Wind Effects on Trees’. B Ruck, C Kottmeier, C Mattheck, C Quine and G Wilhelm (eds). University of Karlsruhe, Germany, 16–18 September 2003, pp. 231–237.
Anderson C J, Coutts M P, Ritchie R M and Campbell D J 1989 Root extraction force measurements for Sitka spruce. Forestry 62, 127–137.
Bailey P H J, Currey J D and Fitter A H 2002 The role of root system architecture and root hairs in promoting anchorage against uprooting forces in Allium cepa and root mutants of Arabidopsis thaliana. J. Exp. Bot. 53, 333–340.
Barker D H, Watson A, Sombatpanit S, Northcutt B and Maglinao A R 2004 Ground and Water Bioengineering for Erosion Control. Science Publishers, New Hampshire, USA, 410 pp.
BGS Sheet 257. 1996 Geological map, Romford (Epping) 1:50000 Series, HMSO, London.
Chiatante D, Scippa S G, Di Iorio A and Sarnataro M 2003 The influence of steep slopes on root system development. J. Plant Growth Regul. 21, 247–260.
Clayton C R I, Matthews M C and Simons N E 1995 Site Investigation, 584 pp. Blackwell, Oxford.
Commandeur P R and Pyles M R 1991 Modulus of elasticity and tensile strength of Douglas for roots. Can. J. For. Res. 21, 48–52.
Coppin N J and Richards I J 1990 Use of Vegetation in Civil Engineering. Butterworths, London.
Cucchi V, Meredieu C, Stokes A, Berthier S, Bert D, Najar M, Denis A and Lastennet R 2004 Root anchorage of inner and edge trees in stands of maritime pine (Pinus pinaster Ait.) growing in different podzolic soil conditions. Trees Struct. Funct. 18, 460–466.
Denis S, Bremand F and Herbert Y 2000 An experimental study on the mechanical behaviour of the maize root system: analysis of the soil-root bond and determination of rigidity modulus. In A Stokes (ed), The Supporting Roots of Trees and Woody Plants: Form, Function and Physiology, pp. 279–285. Kluwer, Dordrecht.
Dupuy L, Fourcaud T and Stokes A 2004 A numerical investigation into factors affecting the anchorage of roots in tension. Eur. J. Soil Sci. 56(3), 319–327.
Endo T and Tsuruta T 1969 On the effect of tree roots upon the shearing strength of soil. Annual report of the Hokkaido Branch, Forest Place Experimental Station, Sapporo, Japan, 167–183.
Ennos A R 1990 The anchorage of leek seedlings: the effect of root length and soil strength. Ann. Bot. 65, 409–416.
Ennos A R 2000 The mechanics of root anchorage. Adv. Bot. Res. 33, 133–157.
Ennos A R, Crook M J and Grimshaw C 1993 The anchorage mechanics of maize, Zea mays. J. Exp. Bot. 44, 147–153.
Fisher N I 1993 Statistical Analysis of Circular Data. Cambridge Univ. Press, Cambridge.
Flora for Fauna. 2002. British native trees and shrubs. http://www. nhm.ac.uk/jubileetrees/british-native-trees/bnt-23.htm. Accessed 1/09/2003.
Genet M, Stokes A, Salin F, Mickovski S B, Fourcaud T, Dumail J and Van Beek L P H 2005 The influence of cellulose content on tensile strength in tree roots. Plant Soil 278, 1–9.
Goodman A M, Crook M J and Ennos A R 2001 Anchorage mechanics of the tap root system of winter-sown oilseed rape (Brassica napus L.). Ann. Bot. 87, 397–404.
Gray D H and Sotir R 1996 Biotechnical and Soil Bioengineering Slope Stabilization: A Practical Guide to Erosion Control. Wiley, New York.
Greenwood J R 2006 Slip4ex—A program for routine slope stability analysis to include the effects of vegetation, reinforcement and hydrological changes. J. Geotech. Geol. Eng., 24, 449–465.
Greenwood J R, Holt D A and Herrick G W 1985 Shallow slips in highway embankments constructed of overconsolidated clay. ICE Int. Sym on Earthworks Failures, London 6–7 March, pp. 79–92.
Greenwood J R, Norris J E and Wint J 2004 Assessing the contribution of vegetation to slope stability. J. Geotech. Eng. ASCE 157, 199–208.
Greenwood J R, Vickers A W, Morgan R P C, Coppin N J and Norris J E 2001 Bioengineering—the Longham Wood Cutting field trial, 128 pp. CIRIA PR 81, CIRIA, London.
Hathaway R L and Penny D 1975 Root Strength in some Populus and Salix cones. NZ J. Bot. 13, 333–344.
Highways Agency 2003 Design Manual for Roads and Bridges. Vol.1. Highway structures: Approval Procedures and General Design. The Stationary Office, London. ISBN 0115524606.
Highways Agency 2004 Manual of Contract Documents for Highway Works. Vol 1. Specification for Highway Works. The Stationary Office, London. ISBN 011552634X.
Kevern T C and Hallauer A R 1983 Relation of vertical root-pull resistance and flowering in maize. Crop Sci. 23, 357–363.
Lyford W H 1980 Development of the root system of Northern Red Oak (Quercus rubra L.). Harvard Forest Paper. 21, 1–29.
MacNeil D J, Steele D P, McMahon W and Carder D R 2001 Vegetation for slope stability. TRL Report 515, TRL Limited, Wokingham, UK.
Mardia K V and Jupp P E 1999 Directional Statistics. Wiley, Chichester.
Miles A 1999 Silva: the Tree in Britain, 400 pp. Ebury Press, London.
Nicoll B C and Ray D 1996 Adaptive growth of tree root systems in response to wind action and site conditions. Tree Physiol. 16, 891–898.
Nilaweera N S 1994 Effects of Tree Roots on Slope Stability: the case of Khao Luang Mountain Area, Southern Thailand, Ph.D. thesis GT-93-2. Asian Institute of Technology, Bangkok, Thailand.
Norris J E and Greenwood J R 2003a Root reinforcement on unstable slopes in Northern Greece and Central Italy International Conference on Problematic Soils, July 2003, Nottingham Trent University, Nottingham, UK, pp. 411–418.
Norris J E and Greenwood J R 2003b In situ shear box and root pull-out apparatus for measuring the reinforcing effects of vegetation. In F Myrvoll (ed), Field Measurements in Geomechanics. pp. 593–597. Swets and Zeitlinger, Lisse.
O’Loughlin C L 1981 Tree roots and slope stability. What’s new in forest research? Forest Research Institute Publication No. 104, Rotorua, New Zealand
Operstein V and Frydman S 2000 The influence of vegetation on soil strength. Ground Improv. 4, 81–89.
Perry J, Pedley M and Brady K 2003a Infrastructure Cuttings—Condition Appraisal and Remedial Treatment. C591 CIRIA, London
Perry J, Pedley M and Reid M 2003b Infrastructure Embankments—Condition Appraisal and Remedial Treatment. C592. 2nd edition. CIRIA, London.
Riestenberg M 1994 Anchoring of thin colluvium by roots of Sugar Maple and White Ash on hillslopes in Cincinnati. US Geological Survey Bulletin 2059-E, Washington, USA, 25 pp.
Schiechtl H M 1980 Bioengineering for land reclamation and conservation. University of Alberta Press, Alberta.
Stokes A 1999 Strain distribution during anchorage failure of Pinus pinaster Ait. at different ages and tree growth response to wind-induced root movement. Plant Soil 217, 17–27.
Stokes A, Fitter A H and Coutts M P 1995 Responses of young trees to wind and shading: effects on root architecture. J. Exp. Bot. 46, 1139–1146.
Stokes A, Ball J, Fitter A H, Brain P and Coutts M P 1996 An experimental investigation of the resistance of model root systems to uprooting. Ann. Bot. 78, 415–421.
Turmanina V I 1965 On the strength of tree roots. Bull. Moscow Soc. Nat. Biol. Sect. 70, 36–45.
Van Beek L P H, Wint J, Cammeraat L H and Edwards JP 2005 Observation and simulation of root reinforcement on abandoned Mediterranean slopes. Plant Soil 278, 55–74.
Waldron L J and Dakessian S 1981 Soil reinforcement by roots: calculation of increased soil shear resistance from root properties. Soil Sci. 132, 427–435.
Watson A 2000 Wind-induced forces in the near-surface lateral roots of radiata pine. For. Ecol. Manage. 135, 133–142.
Wu T H, Beal P E and Lan C 1988 In situ shear test of soil root systems. J. Geotech. Eng.-ASCE 114, 1376–1394.
Ziemer R 1981 Roots and shallow stability of forested slopes. Int. Ass. Hydrol. Sci. 132, 343–361.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2007 Springer
About this paper
Cite this paper
Norris, J.E. (2007). Root reinforcement by hawthorn and oak roots on a highway cut-slope in Southern England. In: STOKES, A., SPANOS, I., NORRIS, J.E., CAMMERAAT, E. (eds) Eco-and Ground Bio-Engineering: The Use of Vegetation to Improve Slope Stability. Developments in Plant and Soil Sciences, vol 103. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-5593-5_7
Download citation
DOI: https://doi.org/10.1007/978-1-4020-5593-5_7
Publisher Name: Springer, Dordrecht
Print ISBN: 978-1-4020-5592-8
Online ISBN: 978-1-4020-5593-5
eBook Packages: Earth and Environmental ScienceEarth and Environmental Science (R0)