Saturday, 28 February 2009

Seasons for Coastal Sydney


For a while I’ve been mulling over the ‘seasons’ in Sydney, and the inadequacy of the traditional autumn-winter-spring-summer system. Of course every place in Australia has its own seasons, and no one system would work across a county of our size and environmental variability. For that reason I’ve contracted my thinking to the Sydney region, and more specifically that lowland strip near the coast where most people in New South Wales live.

I present this table to stimulate debate and discussion. Soon (very soon!) the Botanic Gardens will begin a community monitoring program to get some good data on environmental change in New South Wales, so we can not only nail down the regular seasonal changes but establish a baseline against which we can measure the impact of accelerated climate change. We also hope to use our extensive herbarium collection (of over 1.2 million preserved specimens) to track changes in flowering times and other seasonal behaviour over the last two hundred years.

But for now, I provide the table at the start of this post, with the following footnotes...

*These were my first thoughts on this topic, based largely on the fact that ‘spring flowering’ around Sydney really starts in late July or early August, and autumn in Sydney is not a dramatic change in the way it is in temperate Northern Hemisphere or places like Melbourne and Hobart (and many inland country areas). Of course once you head up into the nearby mountains the seasons are different again – spring is later and autumn does have more meaning.

**Based on the concepts of Rick Kemp (pers. comm.) – Rick has tried to balance climatic and ecosystem changes but accepts that these two don’t always coincide. There are also transition periods between each of these seasons, and subtleties that I haven’t included here.

***While it may be difficult to change the widely accepted four seasons we have inherited from the Northern Hemisphere, as an alternative we could celebrate the start of more relevant seasonal changes around Sydney with celebratory days – for me, of course, I’d select plants for this purpose! Ideally we would use plants that grow locally in the bush but are also grown in our gardens. The Hyacinth Orchid can’t be grown in gardens but it is so distinctive and evocative of the Sydney Summer that I had to include it in this first rough draft… Different Banksia and Grevillea species flower at different times through the year but May is the usual time for the delightful Hairpin Banksia (Banksia spinulosa) and the striking Red Spider Flower (Grevillea speciosa) tends to start flowering in June. But I’m sure there are better plants to use for these seasonal markers and these are party to provoke debate. And a note about Wattle Day – it was gazetted nationally (in 1992) as 1 September, but 1 August seems (to me) to have more resonance as the beginning of ‘wattle season’ in most parts of Australia and would serve to separate the beginning of the ‘spring flush’, again in most parts of Australia, in late July and early August rather than September.

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