Report

Written by Mike Russell

This walk commenced at the green waste dump at the end of Knoll Rd.  We looked at the revegetation area on Dept Main Roads land which is managed by TM Landcare.  It was originally planted by Jim Bolton and helpers and has been managed since by members.  Adjacent to this area is a parcel of forested land purchased by Jim Bolton and given to the National Park. 

 

 

The regeneration area was examined.  

Madeira Vine is still common and needs immediate control.  Solanum seaforthianum was photographed in flower. 

 

 

 

Also photographed was a tall Pencil Cedar (Polyscias murrayi).  Glochidion sumatrensis was also seen.

We walked round the waste dump and started down the old road which is the original access road up to Tamborine Mountain.  The tall open forest consists of Tallow – wood (Eucalyptus microcorys), Sydney Blue Gum (E. saligna]]), Grey Gum (E. biturbinata) and Red Bloodwood (Corymbia gummifera ) growing on basalt.

 

 

We know that Siratro (Macroptilium atropurpureum) bred by CSIRO in Brisbane in the 1960s from South American parents, Glycine (Neonotonia javanica) from Africa and Archer Axillaris (Macrotyloma axillare) from Africa were aerially broadcast onto the northern slopes of TM in the early 1970s to improve the native pastures for cattle grazing.  There is no doubt that roadside colonies of these legumes could easily have arrived from seed transported on vehicles. 

That Silverleaf Desmodium now often called velcro weed (Desmodium  uncinatum) from Central and South America arrived this way is almost inevitable.  It would also have arrived on people’s clothing.  Hard seed may also have arrived in the dung of grazing animals such as cattle, horses and wallabies and other seed eaters such as birds and bandicoots.

 

The native pasture was mainly Kangaroo grass (Themeda triandra).  The invasion by these pasture legumes suppressed it for three reasons: 

1. They fixed nitrogen and raised the nitrogen status of the soil above that in which Kangaroo grass had evolved.
2. They suppressed natural fires on which Kangaroo grass is dependent.
3. They were grazed more frequently and at a heavier rate than Kangaroo grass is adapted. The ground storey part of the ecosystem changed.  Native grasses started to be replaced by nitrogen loving weeds both grasses and non-grass herbs (forbs).  

Then the cattle were removed (although only temporarily) when the area became part of Tamborine National Park (The Knoll section).  Without adequate grazing the legumes became rampant, climbing trees and further changing the environment.

 

This was the weedy mess which confronted us.  Some of the more prominent weeds, apart from the introduced legumes, were:   Cobblers’ Pegs (Bidens pilosa), Palm grass (Setaria palmifolia), Morning Glory (Ipomea indica), Annual Ragweed (Ambrosia artemisiifolia) and Crofton weed (Ageratina adenophora).

 

 

 

As we descended the road surface changed from slabs of eroding basalt to sandstone rocks.  The vegetation changed to open forest with Spotted Gums (Corymbia citriodora var, variegata), Many-fruited Bloodwoods (C. polycarpa), Pink Bloodwoods (C. intermedia), Rough-barked Apple (Angophora floribunda), Small-fruited Grey Gums with orange underbark (Eucalyptus propinqua), Grey Ironbark (E. siderophloia), and Narrow-leaved Ironbark (E. crebra).  There were a few wattles, Rose Oak (Allocasuarina torulosa), Red Ash (Alphitonia excelsa), occasional Batswing Coral trees (Erythrina verspetilio), a pretty Wedge Pea in yellow flower and a patch of Dogwood (Jacksonia scoparia).  

 

 

Down the road the Kangaroo grass became dominant and there were other native grasses and forbs – Hedgehog grasses (Echinopogon spp.), Wild Sorghum (Sarga leiocladum), Windmill grass (Enteropogon acicularis), Barbed Wire grass (Cymbopogon refractus) and Rattle Pods (Crotalaria spp.) and Plectranthus parviflorus. 

 

 

 

Of concern was the increasing amount of Black Spear grass (Heteropogon contortus ) beside the track in the lower part.  This grass has sharp seeds each with a long awn which twists with moisture and pushes the seed head through fur and wool into the hide.  Its spread through coastal areas north of here made sheep farming impossible.