An investigation of the hydrological requirements of River Red Gum (Eucalyptus camaldulensis) Forest, using Classification and Regression Tree modelling

• DOI: 10.1002/eco.46
• Publication Date: 2009-02-24T10:27:51Z
• Authors: Li Wen; Joanne Ling; Neil Saintilan; Kerrylee Rogers
• Keywords: environmental water; camaldulensis; river; crown condition; Social and Behavioral Sciences; red; 01 natural sciences; 333; modelling; forest; flooding history; floodplain; Medicine and Health Sciences; requirements; 0105 earth and related environmental sciences; investigation; Classification and Regression Tree; hydrological; 15. Life on land; River Red Gum; tree; classification; eucalyptus; gum; regression

AbstractRiver Red Gum (Eucalyptus camaldulensis) is widely distributed throughout many water courses and floodplains within inland Australia. In recent years, accelerated decline of River Red Gum condition has been observed in many locations, and field observations of the degradation are consistent with the reduction of flooding. However, there are few publications that quantitatively investigate the relationships between River Red Gum condition and flooding history. We applied Classification and Regression Tree (CART) to model the minimum flooding requirement of River Red Gum forest/woodland in Yanga National Park, located on the Lower Murrumbidgee Floodplain, southeast Australia, using crown conditions derived from historical aerial photographs spanning more than 40 years. The model produced has a moderate reliability with an overall accuracy of 64·1% and a Kappa index of 0·543. The model brings in important insights about the relationship between River Red Gum community type, flood frequency and flood duration. Our results demonstrated that (1) CART analysis is a simple yet powerful technique with significant potential for application in river and environmental flow management; (2) River Red Gum communities on the Lower Murrumbidgee Floodplain require periodic inundation (3–5 years) for a duration of up to 64 days to be in moderate to good conditions; (3) Although the crown conditions of different community types displayed similar degradation trends, they have distinct flooding requirements; and (4) The River Red Gum community in Yanga National Park may be managed as hydrological units given limited environmental water allocations. Copyright © 2009 John Wiley & Sons, Ltd.