Institute of Foresters of Australia

1. Institute of Foresters of Australia

2. Forest Management and the impact onWater Management

3. ScienceHistoryFuture

4. Forest Management and Water Management Warning: Science Content • All land is in a catchment

5. Forest Management and Water Management • Forests and trees do play a key role in catchment behaviour

6. Forest Management and Water Management • Forest Hydrology Research has given some answers

7. Forest Management and Water Management • Forest Hydrology Research has given some answers

8. Forest Management and Water Management • Forest Hydrology Research has given some answers

9. Forest Management and Water Management • How do Mountain Ash Forests grow and flourish?

10. Forest Management and Water Management The trigger for Mountain Ash forest renewal is wildfire Wildfire provides • Heat to open fruit capsules immediately after the fire • Ash bed seed bed with access to mineral soil • Removal of competing vegetation • Removal of canopy to allow additional light to soil surface • Removal of aleopathic responses • Flush of nutrients in ash for early growth

11. Forest Management and Water Management Red Tuesday 12 people die and 1500 homes lost as fire sweep through the Gippsland forests Black Thursday A great fire sweeps across a thinly populated Victoria Wildfires burn through the ranges east of Melbourne and a seedling forest of Mountain Ash is established. One of these seedlings will become the giant Furmston’s Tree. Wildfires burn through Wallaby Creek. The resultant forest of Mountain Ash is now known as the “Big Ash” containing some of the tallest trees in Victoria. 1933 Furmston’s Tree Discovered The History of the Mountain Ash forests in Melbourne’s Water Catchments 1600 1730 1800 1851 1898 1939 2006 Melbourne establishes a series of forested closed catchments where all uses other than water production are banned. Wallaby Creek, Maroondah, O’Shannassy and Upper Yarra. Melbourne sources its water from the Yarra River above Dight’s Falls Melbourne builds its first dam at Yan Yean

12. Harold Furmston discovers a magnificent mountain ash on Mount Monda, near Healesville. It is carefully measured and found to have a girth of 19.5 metres. The tree is named after its discoverer: Furmston’s Tree. The Healesville Shire President soon leads an excursion to the base of the celebrated giant, and bushwalkers make pilgrimages to it. Not only are the mountain ash forests greatly admired for their awesome beauty – they have now become the most economically valuable forest tree in Victoria.

13. Forest Management and Water Management 2000 The Furmston Tree collapses at the end of its life Great Dividing Range Fires burn to the edge of the catchments and strategic firebreaks established to prevent fires entering the catchments. Period of successfully excluding wildfire from Melbourne’s water Catchments Red Tuesday 12 people die and 1500 homes lost as fire sweep through the Gippsland forests Wildfires burn through the ranges east of Melbourne and a seedling forest of Mountain Ash is established. One of these seedlings will become the giant Furmston’s Tree. Wildfires burn through Wallaby Creek. The resultant forest of Mountain Ash is now known as the “Big Ash” containing some of the tallest trees in Victoria. Black Friday Massive fires sweep through the catchments killing large areas of Mountain Ash and establishing regrowth forests Black Thursday A great fire sweeps across a thinly populated Victoria The History of the Mountain Ash forests in Melbourne’s Water Catchments 1600 1730 1800 1851 1898 1939 2006 Melbourne builds its first dam at Yan Yean Melbourne establishes a series of forested closed catchments where all uses other than water production are banned. Wallaby Creek, Maroondah, O’Shannassy and Upper Yarra. Melbourne Board of Works notice reduced water yield from catchments. Commission major hydrological studies and catchment monitoring network. Relationship between water yield and forest age determined and policies adopted to exclude fire from all catchments. Catchments declared as National Parks giving water and conservation objectives. Only Thomson and Yarra Tribs. remain with multiple use objectives and are open for visitors. Melbourne sources its water from the Yarra River above Dight’s Falls

14. Forest Management and Water Management Future of Melbourne’s Water Catchment Management • The forests contain a range of age classes resulting form the wildfires or harvesting . They range from 277, 156, 109, 68 and 26 or less. • Periodic catastrophic Wildfires are a natural part of the ecosystem. • Forests in the open age catchments have a broader range of age classes providing greater diversity.

15. Forest Management and Water Management Future of Melbourne’s Water Catchment Management • The Thomson catchment is dominated by 1939 regrowth. • 68 year old forests are beginning to increase water yield. • 120 ha per year is harvested and regenerated. • It will take a further 100 years to harvest the 40% that is available. • The average age and the water yields are increasing. • The water yields lost due to harvesting are the potential gains not realised.

16. Forest Management and Water Management Future of Melbourne’s Water Catchment Management The next big wildfire will: • Drastically reduce water quality for a 2 to 3 month period where water from burnt catchments will need to be stored or diverted. Additional water treatment may be required. • Provide large areas of regrowth forest that will reduce water yields over the next 10 to 70 years. The catchment research has shown that thinned regrowth can increase water yields. Thinning would normally not be allowed in National Parks and would only be an option in the open catchments.

17. Forest Management and Water Management What is being done elsewhere? • WA Water Corporation has adopted Security through Diversity water supply policy. • Wungong catchment is 13,000 ha of dry sclerophyll forest. • By Spending $20M on active forest management including thinning and ecological burning water yields can be increased. • Water yields will be monitored and are expected to increase by 4 to 6 Gl per year. This is a 25% increase. • The cost of treatment is very competitive at 23 cents per kilolitre compared with desalination at $1.15 per kilolitre.

18. Forest Management and Water Management Sources • Dr Rob Campbell Fire Cycle Booklet (unpublished) • Dr Rob Campbell Streamflow Booklet (unpublished) • ABC Black Friday - Online documentary about 1939 Victorian bushfires. At abc.net.au/blackfriday/ • Batani Frank, Bradshaw Jack, Roger Underwood. (2007) Managing forested catchments for water, timber and biodiversity. ANZIF Conference Proceedings