Managing risks at the Tasmanian Arboretum phill Parsons, President of the Tasmanian Arboretum Inc.

I have mostly enjoyed working in horticulture over the past four decades and as President of The Tasmanian Arboretum I am mindful of the need to manage risk to our living collections so that plant survival and labour efforts aren’t wasted. The Tasmanian Arboretum tree park is being developed and maintained by voluntary workers for everyone’s benefit. It is a not for profit community organisation providing a tourist attraction and a botanical institution for Northern Tasmania. Within 66 ha of parklands just 10 kilometres south of Devonport, we have the world’s largest collection of Tasmanian living woody plants, Southern Hemisphere conifers and plants from northern hemisphere forests. Where space and material have been available, the Tasmanian Arboretum has followed the accepted strategy of planting multiple species in several locations as far from each other as collection layout plans allow. Thus far our losses in this collection have been few.

Southern Hemisphere Conifer Collection Losses of Pehuen or Monkey Puzzle Tree Araucaria araucana appeared to be due to dry conditions or perhaps from choosing the wrong site for the plant’s needs but one that appeared to be reasonable from an aesthetic aspect. Where Araucaria araucana survived we added more in that dip in the ground. Now we have three ages represented. The earliest planting are now almost at the top of a south facing slope. The subsequent plantings to the first were part of our risk management strategy. Last year some damage occurred to the tips of many of the Wollemia nobilis in the grove we planted in our Australian Collection, but not to the several others planted with a south facing aspect in our Gondwana Collection, some 140m distant and at 40m greater in altitude. The cause of the damage is unknown but the trees in the grove

The two age classes of the Araucaria araucana planted in a dip.

had grown at three to four times faster than the lower group and the damage occurred in a particularly long period of low rainfall now being followed by a wet summer. Not all specimens in the grove appeared to be affected. the botanic gardener | ISS 47 March 2017

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