Isolated Trees in Pasture Landscapes Contribute to and Enhance Soil Health: A Study in Central-West New South Wales, Australia

Robyn Provost, Dennis Hodgkins, Anantanarayanan Raman, Helen Nicol


Isolated farm trees are a distinct feature of the Australian landscape, previously part of a forested landscape, until extensive clearing occurred for agricultural purposes post European settlement. A majority of studies has focused on the beneficial effects of tree clusters, such as shelterbelts and windbreaks and little pertains to characterizing the role of isolated farm trees (also referred as isolated farm trees, IFTs). IFTs are generally older than their tree cluster counterparts, with little to no chance of regenerating in a grazed landscape. Both tree clusters and IFTs contribute to the health of the soil by increasing soil nutrients, protecting pastures and stock from harsh weather, reducing erosion levels, providing habitat for vertebrate and invertebrate species and increasing agricultural productivity. With the loss of the IFTs from the landscape, the many benefits they provide have also been lost. The purpose of the study was to examine the role IFTs have on enhancing soil health in pastures using physical, chemical and biological soil-health indicators. Leaf litter and soil sampling and soil CO2 efflux readings were made from beneath the canopy and in the surrounding pasture of nine isolated farm trees (Eucalyptus melliodora, E. viminalis, and E. bridgesiana) in Central-west Tablelands of NSW in spring 2014 and autumn 2015. The results indicate IFTs enhance soil health in pasture landscapes with greater arthropod abundance and diversity, higher rates of soil respiration, greater concentrations of total nitrogen and phosphorous, and lower levels of soil compaction closer to the tree compared with surrounding pasture landscape. Collectively these findings point to a positive influence on soil health in grazed pastures by isolated farm trees. 


Bulk Density; Invertebrates; Isolated Trees; Soil Arthropods; Soil Respiration; Total Phosphorus; Total Nitrogen.


Barnes, P.; Wilson, B.R.; Nadolny, C. and Growns, I. 2009. The influence of individual native trees and grazing regime on soil properties and groundcover patterns in a temperate landscape of NSW, Australia. The Rangeland Journal 31: 405―415.

Blozan, W. 2008. Tree Measuring Guidelines of the Eastern Native Tree Society.Retrieved from measure/Tree_Measuring_Guidelines-revised1.pdf (accessed 30 June 2014).

Bower, C. 2012. Biodiversity Survey and Assessment, Charles Sturt University, Orange FloraSearch, Orange, New South Wales.

Bower, C.; Semple, B. and Harcombe, L. 2002. Eucalypts of the Central West of NSW. NSW Department of Land and Water Conservation, Orange, New South Wales. 60 pages.

Bromham, L.; Cardillo, M.; Bennett, A.F. and Elgar, M.A. 1999. Effects of stock grazing on the ground invertebrate fauna of woodland remnants. Australian Journal of Ecology 24: 199―207.

Brown, K. and Wherrett, A. 2015. Bulk Density—Measurement [Fact Sheet]. Retrieved from http://www. factsheets/bulk-density-measurement (accessed 21 September 2015).

Bureau of Meteorology. 2014. Climate Statistics for Australian Climates. Retrieved from climate/averages/tables/cw_063254.shtml (accessed 12 June 2014).

Department of Primary Industries. 2010. Apple Box [Fact Sheet]. Retrieved from http://www.dpi. resources/private-forestry/farm-plants/Eucalyptus-bridgesiana-Apple-Box.pdf (accessed 24 September 2015).

Eldridge, D.J. and Wong, V.N.L. 2005. Clumped and isolated trees influence soil nutrient levels in an Australian temperate box woodland. Plant and Soil 270: 331―342.

Fischer, J.; Stott, J.; Zerger, A.; Warren, G.; Sherren, K. and Forrester, R.I. 2009. Reversing a tree regeneration crisis. In: Bush Matters: Newsletter of the Conservation Partners Program of the Department of Environment, Climate Change and Water, NSW 12:12. Retrieved from BushMatters12.pdf (accessed 12 June 2014)

Florabank, n.d. (a). Eucalyptus bridgesiana[Factsheet]. Retrieved from species%20navigator/media/html/Eucalyptus_bridgesiana.htm (accessed 12 June 2014).

Florabank, n.d. (b). Eucalyptus viminalis [Factsheet].Retrieved from species%20navigator/media/html/Eucalyptus_viminalis.htm (accessed 12 June 2014).

Florabank, n.d. (c). Eucalyptus melliodora [Factsheet].Retrieved from species%20navigator/media/html/Eucalyptus_melliodora.htm (accessed 12 June 2014).

Gibb, T. and Oseto, C.Y. 2006. Arthropod Collection and Identi-fication: Field and Laboratory Techniques, Academic Press, Massachusetts, USA. 311 pages.

Gibbons, P. and Boak, M. 2002. The value of farm trees for regional conservation in an agricultural landscape. Ecological Management andRestoration 3: 205―210.

Graham, S.; Wilson, B.R.; Reid, N. and Jones, H. 2004. Scattered farm trees, litter chemistry and surface soil properties in pastures of the New England Tablelands, New South Wales. Australian Journal of Soil Research 42: 905―912.

Greenslade, P. 1992. Conserving invertebrate diversity in agricultural, forestry and natural ecosystems in Australia. Agriculture, Ecosystems and Environment 40: 297―312.

Harvey, M. S. and Yen, A. L. 1989. Worms to Wasps: An Illustrated Guide to Australia’s Terrestrial Invertebrates. Oxford University Press, Melbourne, Victoria. 201 pages.

King, K.L. and Hutchinson, K.J. 1976. The effects of sheep stocking intensity on the abundance and distribution of mesofauna in pastures. Journal of Applied Ecology 13: 41―55.

Kovać, M. and Lawrie, J. A. 1990. Soil Landscapes of the Bathurst 1:250 000 Sheet. Soil Conservation Service of NSW, Sydney, New South Wales.

Marsh, N.R. and Adams, M.A.1995. Decline of Eucalyptus tereticornis near Bairnsdale, Victoria: insect herbivory and nitrogen fractions in sap and foliage. Australian Journal of Botany 43: 39―49.

Mbuthia, E.W.; Shariff, J.H. ; Raman, A.; Hodgkins, D.S.; Nicol, H.I. and Mannix, S. 2012. Abundance and diversity of soil arthropods and fungi in shelterbelts integrated with pastures in the central tablelands of New South Wales, Australia. Journal of Forest Science 58: 560―568.

McElhinny, C.; Lowson, C.; Schneemann, B. and Pachon, C. 2010. Variation in litter under individual tree crowns: Implications for scattered tree ecosystems. Austral Ecology 35: 87―95.

Moulin, M.; Lopez, J.; Raman, A.; Hodgkins, D.; Adams, A. and Mannix, S. 2012. Measurement of biological diversity of arthropods and respiration in soils managed under time-controlled and set-stocked grazing practices in Central-West New South Wales. Polish Journal of Soil Science XLV: 17―28.

Oliver, I.A.N.; Pearce, S.; Greenslade, P.J.M. and Britton, D.R. 2006. Contribution of farm trees to the conservation of terrestrial invertebrate biodiversity within grazed native pastures. Austral Ecology 31: 1―12.

Ozolins, A.; Brack, C. and Freudenberger, D. 2001. Abundance and decline of isolated trees in the agricultural landscapes of central New South Wales, Australia. Pacific Conservation Biology 7: 195―203.

Reid, N. and Landsberg, J. 2000. Tree decline in agricultural landscapes: what we stand to lose. Pages 127―166, In: Temperate Eucalypt Woodland: Biology, Conservation and Restoration. Surrey, Beatty and Sons, Chipping Norton, NSW.

Tom, N.; Raman, A.; Hodgkins, D. and Nicol, H. 2006. Populations of soil organisms under continuous set stocked and high intensity-short duration rotational grazing practices in the Central Tablelands of New South Wales (Australia). New Zealand Journal of Agricultural Research 49: 261―272.

White, R. E. 1987. Introduction to the Principles and Practice of Soil Science . 2nd edition. Blackwell Scientific Publications, Oxford. 244 pages.

Wilson, B. 2002. Influence of scattered farm trees on surface soil properties: A study of the Northern Tablelands of NSW. Ecological Management and Restoration 3: 211―219.

Wilson, B. R.; Growns, I. and Lemon, J. 2007. Scattered native trees and soil patterns in grazing land on the Northern Tablelands of New South Wales, Australia. Australian Journal of Soil Research 45: 199―205.

Full Text: PDF


  • There are currently no refbacks.

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.

COPYRIGHT of this Journal vests fully with the National Instional Institute of Ecology. Any commercial use of the content on this site in any form is legally prohibited.