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Spring has officially arrived. The seasonal changes that we see on Tamborine Mountain are subtler than in many parts of the world where spring follows a long, cold, dark winter. Nevertheless spring here still has its particular pattern of natural life cycles, growth and activities. A favourite part of springtime is the sight and scent of flowering plants. How do the plants sense that spring has arrived even if the weather is unseasonably cold?

A major key in regulating plant activity is the change in length of day (ratio of light to darkness in a 24-hour period) throughout the year.

The seasons and length of day are linked because they are a result of the change in the orientation of the Earth relative to the Sun. The Earth’s axis is tilted at an angle of 23.5 degrees. When the top half of the Earth tilts towards the sun it is Northern Hemisphere summer/Southern Hemisphere winter, when the lower half of the Earth tilts towards the sun it is Northern Hemisphere winter/Southern Hemisphere summer. Days are longer in summer and shorter in winter. On the equator there is very little change in position so length of day is an almost constant 12 hours. At the poles there is only one sunrise and sunset per year. These occur about the time of solstice, 21 June and 21 December, and mark the time of maximum tilt of the equator and consequently they are the dates of the longest and shortest days.

Photoperiodism is the term used to describe an organism’s ability to detect changes in the length of day. In plants it is a complex process and the mechanics are not totally understood. The plant has to perceive the ratio of darkness to light in a 24-hour period and then determine the marginal increase of light or darkness. Plants accomplish this through photoreceptors found in their leaves, these light sensitive protein pigments are called phytochromes and cryptochromes. Two forms of phytochrome react differently to the length of darkness and the change in ratio of these forms determines whether light or darkness has increased. The plant then has to communicate this information to another part of the plant to produce the response required. A message protein is produced in the leaf, it then moves through a nerve-like network of chloroplasts and specialised cells to other parts of the plant, such as the shoot tips and triggers the complicated gene activity which produces floral buds. 

Plants that flower in spring have many active pollinators such as insects, birds and bats, and also have an opportunity to set fruit and seed, which mature before the following winter. However there are many plants that flower in other seasons, many temperate species even require a cold spell, called vernalisation, before they will flower, no matter how favourable other conditions are.

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Why does attentiveness to nature matter? In a very fundamental sense, we are what we pay attention to. Paying heed to beauty, grace, and everyday miracles promotes a sense of possibility and coherence that runs deeper and truer than the often illusory commercial, social "realities" advanced by mainstream contemporary culture. ... Our attention is precious, and what we choose to focus it on has enormous consequences. What we choose to look at, and to listen to--these choices change the world. As Thich Nhat Hanh has pointed out, we become the bad television programs that we watch. A society that expends its energies tracking the latest doings of the celebrity couple is fundamentally distinct from one that watches for the first arriving spring migrant birds, or takes a weekend to check out insects in a mountain stream, or looks inside flowers to admire the marvelous ingenuities involved in pollination. The former tends to drag culture down to its lowest commonalities; the latter can lift us up in a sense of unity with all life. The Way of Natural History, edited by Thomas Lowe Fleischner and published by Trinity University Press (Texas)