Physical and Chemical Factors Affecting Native Tree Establishment on Reformed Open-Cut Mine Sites within the Hunter Valley

Abstract

This study details the results of the first systematic investigation of the factors affecting native tree establishment on coal mine spoil within the Hunter Valley. Previous research had largely concentrated on the use of replaced topdressing materials which primarily consists of soil B horizon. The suitability of other spoil material e.g. sandstone, shale and mudstone substrates as media for tree growth, has received little attention. This lack of basic information has meant that this study was intentionally broad and investigated aspects of tree establishment on a wide range of substrates which may deserve more detailed attention. The major aim of the research described herein was to investigate the suitability of a range of substrates for native tree establishment and to develop practical, low cost tree establishment techniques. Specific objectives included identification of physical and chemical spoil characteristics which may be limiting to the germination, survival and/or growth of native tree species. Two major investigation techniques were used. Firstly, controlled glasshouse experiments using potted materials, allowed control of external variables in order that specific problems affecting germination, survival and early growth could be examined. Field experiments further examined glasshouse results and investigated the effect of different substrates and treatments on germination, survival and growth.