Structural patterns and changes in Callitris - Eucalyptus woodlands at Terrick Terrick State Park, Victoria
Environment Australia, May 1999
- Structural patterns and changes in Callitris - Eucalyptus woodlands at Terrick Terrick State Park, Victoria (PDF - 140 KB)
About the report
Callitris - Eucalyptus woodlands originally covered vast areas of the eastern states of Australia from southern Queensland to northern Victoria, but are now poorly represented throughout this region. This study involved a survey and description of the Callitris - Eucalyptus woodland association at Terrick Terrick State Park in northern Victoria. Three distinct vegetation zones were recognised: (1) a dense Callitris zone dominated by Callitris glaucophylla; (2) an open woodland of mixed Eucalyptus microcarpa/C. glaucophylla; and (3) a rocky outcrop woodland dominated by Eucalyptus rnelliodora. The three zones occupied slightly different environments.
Size class analysis showed that Callitris and Eucalyptus species have recruited at different times in the past. Most C. glaucophylla trees resulted from a single recruitment pulse which is though to have occurred between 1865 and the 1870s. In contrast, both E. microcarpa and E. melfodora have continually recruited throughout the past century. Between the 1870s and 1970s, no C. glaucophylla recruitment occurred except in a small plot from which grazing stock were excluded. Eucalyptus microcarpa has recruited abundantly in recent years, which may be due to the removal of grazing from within the Park after 1993.
A dendrochronological study of C glaucophylla confirmed that the major recruitment pulse was between the 1840s and 1880s, but the technique failed to give exact dates.
Historical changes in C. glaucophylla stand structure were examined by sampling old tree stumps. Stump analysis suggested that C. glaucophylla density before the 1880s was only 6-11 trees/ha, although the true density may be underestimated. Successive silvicultural treatments in the dense Callitris zone have thinned the dense 1865 to 1870s recruitment from about 354 trees/ha in the early 1900s to 126 trees/ha now.
This study provides a valuable quantitative picture of historical changes in this remnant woodland.