Friday, 10 March 2017

Plant responses to fire

I have been doing some pruning to encourage tees and shrubs to regenerate and have consulted Dr Google about genera which are likely to respond well.  I'll add to this as I find other material but here are some early finds.  Note that they are of various vintages and not for our region so read with caution.  

Plant Response to Bush Fire 
( This did not behave well when viewing the URL so I have cut and pasted the text below.

The mere mention of bush fire sends a shiver down the spines of victims all across Australia.

What of the plants which can neither run or hide from fire as it comes sweeping through the bush? Adaptation is one of the hallmarks of Australian native flora. Their ability to handle fire sets them apart from flora of other regions in the world. Not only have some of our plants adapted themselves, but some plants cannot exist without fire.

Prof. John Pate from the Botany Department of University of Western Australia has studied the responses of plants to fire. There are two main strategies by plants to survive fire. The first is the ability to sprout new growth from protected parts of the plant, and the second is the use of chemicals from bush-fire smoke to initiate germination of seed.

In a bush area of Wanneroo, north of Perth, recently burnt out by bush-fire, there are already examples of new growth sprouting from blackened branches such as Paperbark, Melaleuca rhaphiophylla. These plants are known as "sprouters", having the capacity to sprout new growth from groups of little buds under the bark. The dormancy of these buds is only broken by the heat of fire.

The second feature of the "sprouters" is their very thick bark which not only protects the buds during fire, but also provides a store of starch. This stored energy is mobilised to start the buds sprouting and feed them until they have sufficient greenery to begin photosynthesis. Trees such as these tend to be deep rooted, up to 15 meters deep, and this gives access to ground water, the fire-scorched surface being bone dry.

Another type of respouter are those plants with a swollen root, or lignotuber, in which sufficient energy is stored to support new sprouts just above ground level. Examples of these are Jacksonia sp. and the Southern River Gum, Eucalyptus rudis.

The process of several years of natural regeneration can be seen in an a area of Kings Park, swept by fire three years ago. It is here that evidence can be seen of the second main survival strategy of seeding. Woolly bushes, Adenanthos sp., members of the cedar family, have not survived the fire, but under their burnt wood are three year old saplings. The species has preserved itself by having fire-resistant seeds. After the fire these have fallen into the nutrient rich ash below. Winter rains initiate their germination.

Similarly, empty seed cones can be seen on a dead Banksia prionotes, Acorn Banksia. The seed cones are adapted to open their valves after having been baked, allowing the seed to fall to the ground. Since these plants take 5 to 8 years to be mature enough to flower and set their own seed, another fire now would eliminate the species.

Research done at the U.W.A. Botany Dept has found that the chemicals contained in smoke are one of the most potent factors in breaking down the inhibitors to germination of bush seeds.

Fire has shaped the bush in Australia in a way which has happened nowhere else in the world, and we are still improving on our understanding on these processes.

For further information about smoke water, contact Kings Park and Botanic Gardens, Fraser Ave, West Perth, ph: 08 9480 3600.

Effects of fire on plants and animals: individual level

  As this one seems to present correctly I just offer the URL for a quite interesting post .

Fire, flora and fauna

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