by Len Gardner
June 1, 2009
What could be crazier than seeing fall foliage -- that blaze of reds, purples, yellows and oranges for which New England is justly famous -- in June? Well, you can. Just go out into our wild areas.
Right now, many Poison Oak plants are stopping photosynthesis and turning their leaves shades of scarlet, crimson and some tones that haven't been named yet. The same untimely fall madness was evident last month in the leaves of Fuschia-Flowered Gooseberry. Even the sedate and sensible Black Sage seems a little wacky. A lot of its leaves are turning yellow, even as its pale lavender blossoms hang on. (to left: Fuschia-Flowered Gooseberry on Lower Laurel Trail 01 June 2009, photo by Jennifer Wood)What's happening here is that these plants are preparing themselves for the season of adversity. The difference between California and the northern and eastern states is that our adverse season is the summer, not the winter. Instead of freezing temperatures and ice, our plants have to contend with months of searing heat and parching dryness. Some are better prepared for this great annual stress than others. All have their adaptations.
One strategy many of our species have in common with those of northern latitudes is deciduousness, the seasonal dropping of some or all leaves. In the north, deciduousness saves tender tissues from frost and ice damage. In our semi-desert climate, it is a way to stop photosynthesis. This makes sense when you realize that photosynthesis consumes water, and water is in short supply. (to right and below: Black sage on Lower Laurel Trail 01 June 2009, photo by Jennifer Wood)Plants stop doing photosynthesis before they drop their leaves. This means they stop producing chlorophyll in the soon-to-be cast off leaves. Chlorophyll is the pigment that gives healthy leaves their green color and is essential in doing the work of photosynthesis. Free of chlorphyll, other underlying pigments, such as carotenoids and anthocyanins, are now revealed. Thus, the leaves briefly turn red or yellow or some combination before dropping off. In no longer doing photosynthesis, these leaves are now nonfunctional. The plant cuts off their water supply and they soon fall away.
When we learn this, we understand that the "unseasonal" colors some of our plants show in May and June are not really unseasonal. They simply reflect a different meaning to the seasons. On the dry hillsides of our local wildlands, summer is not the season of exuberant growth. This is not the eastern or northern forest, where the heat and long days of summer combine with abundant rainfall to produce a frenzy of photosynthesis. On the contrary, the dry heat of summer we experience brings on the killing days, the time that tests each plant to the core.Our summer, then, is not the season to grow; it is the season to survive. For our native plant communities, the living is not easy in the summertime, and relief is still months away. There are further trials and tribulations to come in the Santa Ana winds of October, November and sometimes December. Only after all these challenges do our plants get a break, when (hopefully) winter storms blow in once again.
It is only when you look at our California seasons with the eyes of an Easterner that you think they are off kilter. But they are not so senseless. There is a logic here. It is the grim logic of survival in the face of six or more months of relentless drought. So, we Californians enjoy our fall colors in June and when Easterners tell us we're crazy, we just smile.
For further reading:
http://en.wikipedia.org/wiki/Chlorophyll
Moderate: http://en.wikipedia.org/wiki/Autumn_leaf_color and
http://www.mtcubacenter.org/whats-new/FallColors101807.htm
Harder: http://chemistry.about.com/library/weekly/aa082602a.htm
Do you have an essay you'd like to contribute to the blog? Contact Jennifer at info@natureinorangecounty.com. We can't wait!
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