Environmental Science
articles by Will Kemp

Changes in the population structure of Acacia papyrocarpa (western myall) in chenopod shrubland in South Australia


The arid chenopod shrublands of South Australia have been heavily degraded by sheep grazing since the 19th century. Acacia papyrocarpa is an ecologically important tree in these communities. It is habitat for many species of animals and plants which are not found in the open, it also plays an essential role in nutrient cycling and local hydrology. A. papyrocarpa is a very long lived tree – with some individuals possibly living as long as 1000 years – and recruitment occurs extremely slowly, depending on climate events which occur only a few times a century. Mainly due to grazing by sheep and rabbits, senescent trees are not being replaced by seedlings at a fast enough rate to maintain the population, and the tree and its associated ecosystems are threatened. We counted A. papyrocarpa, assigning individuals to one of nine age classes, and compared the age class distributions with a similar study which was carried out in 2000. This study appeared to show that these populations of A. papyrocarpa have begun to slowly recover. It is not clear what the cause of this recovery is – or even if such a recovery is, in fact, taking place – but, if it is, it may be related to reductions in the rabbit population due to the introduction of myxomatosis in the 1950s and calicivirus in the 1990s. Read the rest of this entry »

Research proposal: Measuring root respiration to locate the growing tips of tree roots

1 Aims

The aim of this project is to assess the viability of using soil respiration measurements to locate the outer extent of tree roots. There is currently no non-invasive method for doing this. It also aims to add to the understanding of soil respiration and its relationship with tree roots. A further aim is to assess the tree protection zone defined in AS4970 (Protection of trees on development sites) and determine its adequacy.

2 Background and knowledge gaps

There has been a considerable amount of research conducted into soil respiration over two centuries, and numerous studies have attempted to isolate its components – which include respiration by roots and organisms in the rhizosphere (Luo & Zhou, 2006). Read the rest of this entry »



Terminalia are shrubs or trees of the Combretaceae family. There are approximately 200
species distributed thoughout the tropics globally, of which 29 species occur in Australia.
Most species are deciduous. Terminalia species usually have branches growing at a wide
angle to a central leader, growing sympodially, with leaves clustered at the ends of the
branchlets. This gives them a characteristic pagoda like appearance (Australian Biological
Resources Study (ABRS) 1990, Department of Land and Resource Management (DLRM)

Leaves are petiolate, arranged spirally, and often have glands and domatia. In common
with all other members of the Combretaceae family, leaves are simple, with margins entire,
and without stipules (ABRS 1990, DLRM 2012a).

Read the rest of this entry »