The Mulloon Institute's tree planting programme is an integral part of our landscape rehabilitation programme. In addition to eucalypts, we have a commitment to creating wood rows of specific native and non-native deciduous trees in order to meet the following objectives:
- Provide readily compostable leaf fall to enrich the soil, increase soil humidity and temperature during winter
- Reduce summer litter or litter that quickly decomposes in summer to reduce fire load
- Deflect Radiant heat during summer and specifically the fire season
- Be slow to ignite and burn
- Slow an approaching fire-front
- Create a wind-break in summer to reduce dehydration and top-soil loss
- Survive in a low-rainfall environment
While not all species will meet all of these objectives we aim to select tree species that assist us to meet as many of these objectives as possible.
Fire Mitigation Read More...
- Moisture content - most natives have a moisture content of 80 to 150% of their oven dry weight (ODW) while deciduous trees contain 250 to 400% of their ODW. The higher the moisture the slower the ignition. Lush, green material must be dried out by the fire before it will ignite.
- Ash content , or the solid matter left after burning - tends to be made up of alkaline compounds that are naturally fire retarding, so low ash plants like Eucalypts (usually < 10% ash) will glow (and therefore can cause further flare ups) for longer periods than deciduous trees of 30 to 40% ash. This ash cools quickly and can smother remaining hot spots.
- Volatile oil ontent - in Eucalyptus, Melaleuca, Callistemon and other Myrtaceae range up to 5% oil this is generally higher than other plants. When heated, this oil can explode, intensifying the heat ahead of the fire front. This in turn heats and ignites more volatile oils.
- Ignition temperature - plants with higher oil levels tend to have lower ignition temperatures, the Myrtaceae family ignite at 80 to 100 degrees Celsius, so they burn with less preheating than other species which ignite at 200 to 400 degrees. Loose, flaky or rough bark will trap embers. This can produce enough heat for ignition.
- Salt content - is more related to location than to species. Plants growing in saline conditions will have a higher salt content and this retards burning.