As with most things in life, creating a National Park isn’t easy. It’s far better to leave things the way they are than to try to fix them later! One of the most significant issues the Organ Pipes National Park faces is dying trees. Most species of wattle tree have a lifespan of 15-20 years. Large areas of the park were planted with wattle trees at the same time, and subsequently many of the trees in the park have reached the end of their life span within a few years of each other.
Rabbits compound the problem by preventing the natural regeneration of trees. The return of wallabies (who prefer shrubs to grass) to the Park has also made it harder to establish vegetation.
Another concern is the survival of the band of Allocasuarina (she-oak) trees that can be found on the top of escarpments in the Park. It is thought that they were planted in the Park more densely than they would have occurred naturally, and unfortunately they are not reproducing naturally.
A stand of trees planted at the same time will result in all of the trees reaching the end of their life at the same time. Trials have been undertaken by the FOOPs group to see what is preventing the natural regeneration of these trees, but the cause is not yet clear.
Activity
Design a trial to test what factors are preventing the regeneration of she-oaks. Make sure you include an experimental control.
This image shows cones that the she-oak trees drop on the ground. It is therefore unlikely that the lack of she-oak reproduction is caused by a lack of dropped cones.
Exclusion fencing like that pictured has been used to see if that can help explain the lack of regeneration.
Pictured is the main flat, an alluvial plain. The trees here were most likely planted too close together and need to be thinned out – it is unlikely that the area would have looked like this originally. Part of the problem is that the previous understorey of Acacia trees experienced a mass death when they all reached the end of their life at the same time.
Activity
Summarise some of the problems that are faced with re-establishing an ecosystem after it has been destroyed. Suggest some ways that revegetation practices used at the Organ Pipes National Park could be improved.