Willows along watercourses: managing, removing and replacing

Regular inspections of willow lined watercourses after floods to:
• Identify and remove logs or branches that have lodged in the area that may develop into new trees.
• Identify and organise the removal and replacement of trees that have fallen into the stream.
• Identify and organise the removal and replacement of trees that are encroaching on the stream and growing in the stream bed.

Regular inspections of willow lined watercourses during spring months to:
• Identify species that have potential to spread by seed so they can be removed before they release seeds.
• Determine whether seedlings are developing on the stream bed or bank or on sand/gravel islands so they can be removed and replaced before they grow larger and become more difficult to handle.

A yearly lopping/pruning program for all willow trees that remain along the watercourse so that:
• branches do not grow large and hang over the stream, catching debris during high flows;
• large, top-heavy trees are prevented from toppling; and
• increased sunlight is able to reach beneath willow canopy, allowing native grasses and shrubs to regenerate.

• Any large scale willow removal and replacement programme should be carefully planned with advice from staff at your local Catchment Management Authority Officers are available to assist in planning and advising on willow removal and replacement suitable for your situation.
• If possible, willow roots should be left undisturbed. Remove only tree branches and trunks and plant around them with indigenous stock.
• If possible, trees should be killed before they are physically removed.
• Any large scale willow removal programme should only be carried out in stages over several years.
• Willow removal on outside bends or in streams which are actively deepening or widening should only be carried out under supervision of trained staff from Catchment Management Authority.
• All willow removal programmes should include follow-up visits to ensure successful treatment and to remove any twigs or branches washed from upstream lodging and regenerating in the area.
• All willows removed should be replaced with more suitable indigenous trees, shrubs and grasses to ensure continued bank stability and stream health.
• Willow removal programs should commence at the most upstream area and gradually work in a downstream direction.

• Cut down the tree leaving a stump about ½ to 1 metre high. (Stack all lopped timber well above flood height in a dry position. Burning twelve months later may be required if stems are not dead).
• Immediately chop up the top of the freshly cut stump with an axe using vertical strokes. This creates hollows that allow rainwater and pathogens to invade the heartwood of the tree.
• Plant indigenous trees shrubs and grasses.
• Follow up on several occasions at two monthly intervals. Re-chop the stump, prune any new shoots and remove any branches left behind that may reshoot. After six months or so, the tree will become stressed and should eventually die.
• Allow the stump and roots to rot away gradually, without removing the root system.

• Choose a dry day in early Autumn.
• With an axe/machete, ringbark the tree making a series of cuts about 50 mm wide around the entire circumference of the stem (below the first branches or around each of the lower stems). The cuts need to penetrate the sapwood directly beneath the bark but should not enter the heartwood of the tree. Angle the cuts so that the herbicide does not run out.

• Inject/spray registered herbicide into the cuts using a syringe (needle removed) or a sheep/cattle drench pack. This must be done immediately after the cuts are made (ie. within seconds).
• Monitor the tree in spring for signs of growth. If reshooting occurs, re-cut and apply herbicide again. Remove any stray branches.
• Leave tree to gradually disintegrate.
• Protect and rehabilitate the area with fencing. Plant suitable indigenous trees, shrubs and grasses.

• Choose a dry day just before leaf fall (early Autumn). Lop the tree trunks, leaving a stump ½ - 1 metre high. (Stack all lopped branches and broken twigs well above flood height for burning in twelve months.)
• Paint the freshly cuts stump immediately with herbicide, taking care not to spill the herbicide and damage the surrounding area.
• Monitor the tree in spring for signs of growth. If reshooting occurs, apply herbicide again. Remove any stray branches.
• Leave the stump to die, allowing it to rot and disintegrate gradually.
• Protect and rehabilitate the area with fencing. Plant suitable indigenous trees, shrubs and grasses.

• Ringbark and poison the stems in early Autumn, as outlined above.
• Monitor in spring for signs of tree growth.
• If poisoning is successful, remove tree trunk and roots with excavator, being careful to cause minimal disturbance to surrounding soil.
• Stack all debris well above flood height, ready for burning in twelve months, if required.
• Inspect the removal site and clean up any remaining branches, twigs or roots to prevent reshooting.
• Inspect site again in late spring and remove any branches, twigs and re-shooting roots.
• Protect and rehabilitate the area with fencing. Plant suitable indigenous trees, shrubs and grasses.

• Catchment Management Authority (the River Management Group)
• Department of Sustainability and Environment, Victoria
• Greening Australia
• National Herbarium. Royal Botanic Gardens, Melbourne.
• Environmental Consultants.

• LC0117: Willow identification guide
• LC0118: Willows along watercourses: an introduction
• LC0119: Willows along watercourses: their impact compared to natives
• LC0120: Watercourse revegetation using indigenous plants