Closed eucalyptus forests represent a seral stage in the

transition from sclerophyllous forest and woodland to

rainforest. In the mapping process, sclerophyll rainforest

transitions were identified by the presence of the

component sclerophyll species in the canopy at widely

varying levels of cover dependent on the stage of the

transition process, and where, below the main

sclerophyll canopy, a closed canopy of vine forest species

could be detected. The structure and composition of the

non-sclerophyll component is variable depending mostly

on soil factors such as fertility, depth and drainage.

The successional process invariably begins with thecessation of regular landscape burning in modern times.Whilst this process is affecting a number of eucalyptdominant open forests, the floristic associations within thisformation provide an ecological unit which is consistentlyrecognizable across the landscape. It must however beacknowledged, as was done by Tracey (1982) that thenature of the understorey may vary according the length oftime since the last fire event. Therefore this formation mayalso encompass some open forest communities wherelower structural layers are relatively free from vine forestspecies.

The formation is represented by two floristic associationsdominated by Corymbia torelliana (19a) and Eucalyptuspellita (19b). The Corymbia torelliana dominant association,analogous to Tracey's type 13b forest, is intimatelyassociated with drier marginal areas of Araucariannotophyll vine forest. The suite of associated canopyspecies is variable, commonly comprising Eucalyptuspellita, Eucalyptus tereticornis, Corymbia intermedia andAcacia spp. Corymbia torelliana frequently intrudes intothe margins of adjacent vine forest communities, being arelict of the process of succession from open forest torainforest. The species is relatively tolerant of shading andunlike other eucalypt species, is capable of regenerationwithin shaded forest margins.

Association 19b (equivalent to Tracey's 13a forest) istypically a wetter forest type, transitional to a mesophyllrainforest community. Eucalyptus pellita is invariably thedominant sclerophyll species although Corymbiaintermedia and Corymbia tessellaris may form prominentcanopy components. Colonising rainforest species typicallyinclude Deplanchea tetraphylla, Polyscias elegans,Melicope elleriana, Alstonia muelleriana and Acacia spp. Inthe Julatten to Bloomfield region, this association mayinclude areas of open forest with a shrubby understoreyand occasionally a grassy groundcover.

Facts and figures

Major alliances

Closed eucalyptus forestsPresent extent 40,190haArea protected 16,094ha

Geography

This is a widespread natural formation which occupiesextensive areas on the interface between eucalypt openforest and rainforest. Vegetation association 19a isextensive in the moist climatic zone where it typicallyassociates with Araucarian notophyll vine forest. Majoroccurrences are mapped in the Bloomfield, Kuranda,Kirrama and Bilyana areas, occupying areas both on theeastern and western margins of the rainforest massif.Association 19b is typically found on foothills in the wet andvery wet zone with extensive occurrences in the Mossman,Julatten, Daintree, Mission Beach and Bilyana regions.Both associations occur on a range of geologies and soiltypes.

References

Tracey, J.G. (1982). The Vegetation of the Humid TropicalRegion of North Queensland. CSIRO, Melbourne.

Closed eucalyptus forests (vegetation codes 19a-19b)

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SCLEROPHYLL AND SCLEROPHYLL

RAINFOREST TRANSITIONS

OF THE WET TROPICS BIOREGION

wettropics.gov.au

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Impacts and changes

The transitional nature of this formation can be attributedto landscape wide changes to forest burning regimes.These forests have been derived from communities with awell developed ground cover and sparse understorey,which have been destabilized by the gradual or abruptremoval of fire.

Key values

These communities have evolved as major components ofthe landscape as result of disturbance and destabilisationcaused by changing fire regimes.

Threatening processes

None observed.

Tenure

Well represented within major national parks and stateforest areas in the Wet Tropics bioregion. Extensive areasare contained within the World Heritage Area.

Management considerations

• Maintenance burning on woodland margins

• Monitoring and maintenance of edge effects infragmented remnants.