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Survival Against the Odds

Trees face many challenges in their (hopefully) long lifetimes. Our three iconic trees (Eucalyptus, Figs and Macadamias) are extraordinarily well-adapted to the changing seasons of the often-harsh Australian climate.

The survival of these trees is due to their ability to thrive against not only the challenging conditions of nature, but also the choices that humans make.  

Weeds take over the space that native plants need

Weeds are plants introduced into the landscape that quickly become invasive. At the Australian Botanic Garden Mount Annan staff work hard to clear invasive species across the 416 hectares of diverse land in the Garden, with African Olive (Olea europaea subsp. cuspidata) being the worst of the weeds. It's hard to comprehend the scale of the ecological damage across Australia from plants such as the African Olive, Lantana and Prickly Pear.  But by reintroducing plants back into their natural habitat, we can fight back against weeds. Read more here about how the Australian Botanic Garden is removing weeds and making way for native plants.  

Lightning

Trees, because of their height, are natural lightning rods. When a tree falls victim to a strike the damage can be minimal or quite literally explosive. In most trees, the layer just under the bark contains moisture. Since water is a better electrical conductor than wood, lightning striking a tree tends to travel just underneath the bark. The explosive expansion of the lightning's return strike will blast off the bark, and sometimes some of the wood, along the length of the lightning channel. The result is visible scarring along the trunk of the tree. Some trees escape completely unharmed by a direct hit, while others sustain moderate damage to total failure (death). Lightning strikes can kill individual trees, plus some of the plants growing around their base. On a positive note, the dead trees may provide wildlife habitat for years to come.  

Land loss due to development

All over Australia, trees are under threat from logging and land clearing for houses to be built. But sometimes, something bigger than a house needs to be built! Construction of the new airport in Western Sydney will require the removal of approximately 1,150 hectares of vegetation. Around 25% of the vegetation is native plants. The Australian PlantBank has been asked to help with an important conservation project by saving several threatened plants growing at the airport site. Seeds and cuttings collected from the plants will be used to grow new stock at the PlantBank nursery at the Australian Botanic Garden. There they will be available for future conservation projects.  

Theft

It is a sad occurrence, but plant theft is a real thing all over the world from personal gardens through to botanic gardens and parks. Plant theft is illegal, and thefts carry heavy penalties. Any person that tries to remove, uproot or causes damage to any tree or other vegetation, is guilty of an offence – this includes taking cuttings of plants within a botanic garden. When plant thieves do strike at the Royal Botanic Garden Sydney, they are very likely to be caught red-handed on CCTV. 


Activities - Survival against the odds

1. Thinking Big 

Use ‘Think, Pair, Square, Share’ to talk about trees. Ask some big questions:

  • In what ways can you kill a tree? 
  • Can we breathe because of trees? 
  • Where does paper and cardboard come from? 
  • Why would someone steal a plant or tree? 


 

2. Mind mapping 

We’ve learnt about four major threats to trees: weeds, lightning, land loss and theft. Think of four or more threats to trees and add them to the mind map. Then choose two that you think are the worst threats and discuss with your class.

3. Surveying the playground 

What are some threats to the trees in your playground? Use survey skills to complete the worksheet.

 Activity Sheet >