Saturday, August 14, 2010

A Weed and a Pest



Many years ago, about 6 or 7 species of coral trees were promoted by the nursery industry as a beautiful and easily grown ornamental tree. They were right on both counts. Coral trees have bright red flowers from mid winter to mid spring, and are very easy to grow - in fact, far too easy. They were known as instant trees - in fact it was well known that you could break off a large branch and just stick it in the ground and watch it grow! Two of the species became problem weeds.

The first is the Indian Coral or Cockspur Coral Tree (Erythrina crista-galli). This species spreads by seeds and vegetatively. The seed are known as ‘sea beans’ because of their ability to float with the currents. They have become a weed in many areas of Australia, choking creek banks.

The second is the Common Coral Tree (Erythrina x sykesii) seen predominantly along many of our creeks, and also in public parks. It is a hybrid so thankfully does not produce seeds, but spreads readily vegetatively. Logs, branches and even twigs readily regrow. The species also coppices and suckers. The wood is very weak, breaking easily, thereby spreading. Thankfully Newcastle lost many of these in the major storms of recent years, however those that fell over and remained on the ground have now formed huge coppices. They have nasty thorns, a prick from which quickly becomes infected if not treated.

Noisy Miners are one of the few native birds to have become serious pests in their own country. They force other native birds from areas they have taken over including suburban gardens and Eucalyptus woodland habitat. In doing so they damage and potentially destroy it by upsetting the balance between flora, insects and other fauna. To compound the damage, some birds like the Grey-crowned Babbler and Regent Honeyeater whose habitat Noisy Miners have usurped, are rare or endangered.

Another concern is that the Noisy Miners may not be eating the range or numbers of insects previously consumed by the displaced birds. This has the potential to lead eventually to the death of trees from insect damage, and the loss of whole woodland communities of plants and animals.

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