This post really requires a drum role or fanfare.
With permission, I am posting a scanned copy of ‘The Crucial Role of Willows in Sustainable River Management’, by Professor Haikai Tane. I will also lodge this in our useful publications page.
Click on the image below to download the PDF.
This is an excellent resource for anyone seeking to explore the reality of willows within an ecological-thinking perspective (as opposed to a reductively-compartmentalised nativist one). The research presented is mainly based on a New Zealand environmental context, but there are obvious parallels with the Australian situation. There is ample food for thought for Landcarers here.
I, for one, am very grateful that Prof. Tane has allowed this to be shared with us. I’m sure any feedback or discussion would be welcome.
Commercial copyright restrictions apply, as outlined on the second page. Any inquiries regarding further use or reproduction should be directed via the contact details listed there.
As an introduction, I provide the document’s summary (pg. 5) here:
“Grievously misunderstood in NZ today, willows may well be the world’s most widely propagated and planted tree in temperate climes, for managing wetlands, stabilising streams and restoring the environmental health of riparian zones. Viewed from the broad perspective of socio-economic and ecological benefits, willows are without a doubt New Zealand’s most important riparian trees.”
“For more than 100 years willows have been propagated, planted and encouraged to naturalise in New Zealand for their pollen, nectar, shade, shelter, timber, stock fodder in droughts, clean burning firewood, willow canes, medicinal charcoal and floral materials. Willows provide wildlife habitats that have proven ideal for traditional fishing and fowling activities commonly practised among indigenous Pacific peoples. Willow is also the most widely used plant material for conservation of stream, river and lakes and protection of road and rail infrastructure. In New Zealand’s riparian zones where agriculture and apiculture are intricately linked, willows are also indispensable for sustainable farming, because New Zealand farming requires very large populations of honeybees to ensure productive farm pastures and pollination of seed crops, berry bushes vines and tree crops. In most parts of rural New Zealand, willows are the main and most reliable source of spring pollen and nectar to build up populations of honeybees. Without doubt, willows are integral part of the natural and cultural heritage of rural New Zealanders nearly everywhere they live.”
“Willow removal programs disrupt and undermine ecological processes in critical riparian zones. Willows are fundamental in controlling aquifer systems and removing them threatens the stability stream banks and beds. Removing willows can generate slugs of nutrient and sediments, which then trigger algae explosions with toxic residues. Because poisons sprayed to kill unwanted plants and prevent willow regrowth are toxic to in-stream macro-invertebrates, they kill algae eating biota. With willow removal programs, stream ecosystems receive a triple whammy: algae explosions from accelerated sediment and nutrient discharges; severe damage to riparian ecostructures, which control aquifer and springs, and; systemic poisoning of riparian biota. The result is a rapid decline in stream health, stream flows and the quality of water.“