This is the third of a four-part article by BEC member GEOFF DAWE, regenerator consultant for the Cumbebin Wetland in Byron Bay.

Part 3 Weed Succession and replacement at Cumbebin

 

Chemical free bush regeneration, being particularly labour dependent, produces rapid recognition that human energy is most expended on many stemmed plants in any given area such as grasses, and is least expended on few stemmed plants in any given area such as trees.

 

In other words, exotic trees are not as difficult to control as exotic grasses. As a consequence, weeds are farmed rather than removed, and there is the allowance of a weed succession where some weeds actually work to inhibit the energy of others:

 

 

Wild Tobacco (Castor Oil plant similar)

 

Not seen as a threat to native regeneration. In fact consideration is being given to broadcasting it among Lantana.

 

Many species of native birds feed from it. It therefore aids native regeneration. It provides rapid soil shading and therefore helps to inhibit grasses. Maintenance requires that it not be dominated by other weeds such as Banna grass or Morning Glory, so these weeds are cut from it.

 

Wild Tobacco has a relatively short life span and tends to die of its own accord after approximately three years and certainly after heavy shading by natives.

 

In common with all plants that die, it leaves decayed roots in the ground which become channels for the freer passage of air through soil and therefore increases soil microflora and fauna. In effect it acts as a digger of the soil.

 

One could envisage that in a society that looks more towards the long term, garden beds and orchards would be premeditated years ahead of their use and sowed with Wild Tobacco (and perhaps other plants) in order that the era of the turning of the soil practised by humans for so long comes to a close. Certainly in bush regeneration the deliberate removal of Wild Tobacco is more an act of destruction of the expansion of native habitat than an aid.

 

Its difficulty is only its exoticness and that is overcome easily by natural regeneration occurring automatically, or the planting of native trees at closed canopy spacings in its vicinity. Branches of Wild Tobacco are cut out of the way of native trees, and that organic matter aids native growth.

 

Lantana

 

An easily controlled weed that works to improve soil friability, and to provide shade to soil over-exposed to sun through tree removal. In reafforestation areas it is not removed but pruned as a bush or hedge.

 

It is ironic that it was originally brought to Australia as a hedge plant and that chemical free bush regeneration over 200 years later sees its usefulness as a hedge plant. In areas of intense Lantana growth, combined access trails and planting and/or native regeneration areas are cut one metre wide.

 

Planting distances are arbitrary. In areas where natural regeneration is strong or is expected, metre wide swarths are kept clear whilst watching for native seedlings.

 

Hedges are maintained with standard hedge shears or with a sharp machete or sage grass knife, but initial cutting of metre wide planting/walking/natural regeneration areas is done with machete and loppers.

 

The difficulty of Lantana is that initial cutting takes quite some time with canes being up to 50 mm thick, and cut material needs to be cut into smaller lengths in order that it may “lay down” in slashed areas. But its difficulty, as I promised in my previous article (Noticing and Using the Energy of Weeds) is its weakness when it comes to selecting for the growth of natives above that of the weed.

 

Because thick canes take a comparatively long time to grow, a month's growth, about the space of time before a return visit, yields comparatively thin branches which are quickly trimmed. Lantana maintenance is very easy when compared to its initial cutting. Hedges can be cut shorter in winter whilst native seedlings require more sun, or be left to grow longer in summer to provide greater shade for optimum growth of native seedlings.

 

In areas where native trees already have some maturity and Lantana has draped itself over the trees, enough vines are cut at ground level to ensure tree survival, but often many canes are left to provide further shade to soil and to prevent secondary weed infestation by difficult to control grasses.

 

In this way Lantana acts as a partial screen and therefore more obviously aids the work of bush regeneration.

 

Lantana diminishes in energy as shade from natives intensifies. Eventually, it has little “will” to remain and eradication becomes unnecessary. In fact under a closing canopy situation, the reduced vigour of Lantana allows it to occupy a lower storey position where it is able to continue its work of provisioning animal life and soil, without threat to a dominating native system.

 

 

Read Part Four of Geoff's article