Effects of two contrasting canopy manipulations on growth and water use of London plane (Platanus x acerifolia) trees
- 332 Downloads
Two contrasting canopy manipulations were compared to unpruned controls on London plane trees, to determine the effects on canopy regrowth, soil and leaf water relations.
‘Canopy reduction’, was achieved by removing the outer 30 % length of all major branches and ‘canopy thinning’, by removing 30 % of lateral branches arising from major branches.
Total canopy leaf areas recovered within two and three years of pruning for the canopy-thinned and reduced trees respectively. Canopy reduction increased mean leaf size, nitrogen concentration, canopy leaf area density and conserved soil moisture for up to 3 years, whereas canopy thinning had no effects. Another experiment compared more severe canopy reduction to unpruned trees. This produced a similar growth response to the previous experiment, but soil moisture was conserved nearer to the trunk. Analysis of 13C and 18O signals along with leaf water relations and soil moisture data suggested that lower boundary layer conductance within the canopy-reduced trees restricted tree water use, whereas for the canopy-thinned trees the opposite occurred.
Only canopy reduction conserved soil moisture and this was due to a combination of reduced total canopy leaf area and structural changes in canopy architecture.
KeywordsLeaf area Pruning Soil moisture Stable isotopes Subsidence
This work was funded via the Department of Environment, and Food and Agriculture, Horticulture LINK 212 with contributions from Department of Communities and Government, the Highways Agency, the Association of British Insurers, the East Malling Trust and Delta-T Devices Ltd. We thank the Building Research Establishment, Delta-T Devices Ltd, the Arboricultural Association, and Drs Giles Biddle and Mike Fordham for their technical support and contributions. We thank Dr Stephen Young for his extensive advice and the statistical analyses of the soil moisture deficit data.
- Atkinson D (1980) The distribution and effectiveness of the roots of tree crops. Hortic Rev 2:424–490Google Scholar
- Berry G (1964) The evaluation of Penman’s natural evaporation formula by electric computer. Aust J Appl Sci 15:61–64Google Scholar
- BS 3998:2010 (2010) Tree work recommendation. British Standards Institute, LondonGoogle Scholar
- Cepuder P, Evett S, Heng LK, Hignett C, Laurent JP, Ruelle P (2008) Field estimation of soil water content, a practical guide to methods, instrumentation and sensor technology, Training course series No 30. International Atomic Energy Agency, Vienna, p 131ppGoogle Scholar
- Loss Prevention Council (1995) Subsidence and domestic housing survey: analysis of results, LRP4:1995. Loss Prevention Council, Boreham WoodGoogle Scholar
- Cutler DF, Richardson IBK (1997) Tree roots and buildings, 2nd edn. Addison Wesley Longman Ltd, HarlowGoogle Scholar
- Day SD, Wiseman PE, Dickinson SB, Harris RJ (2010) Contemporary concepts of root system architecture of urban trees. Arboricult Urban For 36:149–159Google Scholar
- Delta–T Devices (1999) HemiView User Manual Version 2.1 Delta-T Devices Ltd, Cambridge UKGoogle Scholar
- Development Core Team R (2008) R: A language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Doornkamp C (1993) Clay shrinkage induced subsidence. Geophys J Roy Astron Soc 159:196–202Google Scholar
- Driscoll R (1983) The influence of vegetation on the swelling and shrinking of clay soils in Britain. Geophys J Roy Astron Soc 33:93–105Google Scholar
- Dunn JM (2005) The effects of two contracting canopy manipulations on the growth and water use of Prunus avium. PhD thesis University of CambridgeGoogle Scholar
- Fordham SJ, Green RD (1980) Soils of kent, soil survey bulletin No. 9. The Soil Survey, Rothamsted Experimental Station, HarpendenGoogle Scholar
- Head GC (1969) The effects of fruiting and defoliation on seasonal trends in new root production on apple trees. J Hortic Sci 44:175–181Google Scholar
- Kjelgren R, Clark J (1992) Microclimates and tree growth in three urban spaces. J Environ Hortic 10:139–145Google Scholar
- Kozlowski TT (1971a) Growth and development of trees, volume I seed germination, ontogeny, and shoot growth. Academic, LondonGoogle Scholar
- Kozlowski TT (1971b) Growth and development of trees, volume II cambial growth, root growth, and reproductive growth. Academic, LondonGoogle Scholar
- London Tree Officers Association (1995) A risk limitation strategy for tree root claims. London Tree Officers Association, Hosted by Islington Council, LondonGoogle Scholar
- Morris DA (1996) Hormonal regulation of sink-source relationships: an overview of potential mechanisms. In: Zamski E, Schaffer AA (eds) Photoassimilate distribution in plants and crops. Marcel Dekker, New York, pp 441–465Google Scholar
- VSN International (2011) GenStat for Windows, 14th edn. VSN International Hemel Hempstead, UKGoogle Scholar
- Weiner J (2004) Allocation, plasticity and allometry in plants. Build Res Inf Evol Syst 6:207–215Google Scholar
- Wood J (1999) Leaf area of a single tree. Hemi view application note. Delta-T Devices Ltd, Cambridge UKGoogle Scholar