Present address: Department of Botany, La Trobe University, Bundoora, Victoria 3083, Australia; Tel. +61 3 9479 2218; Fax +61 3 9479 1188
Effects of forest soil desiccation on the growth of Eucalyptus regnans F. Muell. seedlings
Version of Record online: 24 FEB 2009
1996 IAVS - the International Association of Vegetation Science
Journal of Vegetation Science
Volume 7, Issue 4, pages 487–496, August 1996
How to Cite
Ashton, D.H. and Kelliher, K.J. (1996), Effects of forest soil desiccation on the growth of Eucalyptus regnans F. Muell. seedlings. Journal of Vegetation Science, 7: 487–496. doi: 10.2307/3236297
- Issue online: 24 FEB 2009
- Version of Record online: 24 FEB 2009
- Received 19 July 1994; Revision received 5 September 1995; Accepted 29 November 1995.
- Ash-bed effect;
- Eucalyptus forest;
- Forest regeneration;
- Wet sclerophyll forest
- Ross (1993).
Abstract. The growth rate of Eucalyptus regnans seedlings in their first year can be much increased if the soil is first dried and then rewetted. The ratio of growth on predried soil to growth on undried soil (the Growth Ratio or GR) reaches a maximum at air-dryness (pF 6.0–6.4). In E. regnans forest soil, GR is greatest in humus-rich topsoil and declines with depth. The effect of air-drying persists for several months after rewetting when soil is stored under glasshouse conditions. It is largely unaffected by repeated drying and wetting, by the rate of drying or by the season of collection. The mixing of dried and undried soil or the placement of a layer of dried soil above undried soil produces an enhancement of growth proportional to the amount of dried soil added. Firing of a litter layer above soil at wilting point increases subsequent seedling growth to that in air-dried soil. The addition of ash from a litter fire to undried soil produces an increase in growth approximately equal to that caused by air-drying
The drying effect is most pronounced in soils from mature E. regnans forest and nearby brackenland and is less in dense younger forest, frost-hollow grasslands and old grassy gaps in the mature forest. The effect is restored by the inoculation of E. regnans mycorrhizal roots from both dried and undried soil. The effect varies along an gradient from 500 to 1500 m a.s.l. and is a maximum in the wet E. regnans climatic zone and a minimum in zones or local aspects where forests are normally subject to frequent drying. The stimulatory effect on seedling growth in soils of the E. regnans zone may have an effect on the outcome of competition during regeneration in large gaps. Part of the growth responses previously ascribed to the ‘ash-bed’ effect may be due to the desiccation effect in these soils.