Posted by: Rob Viens | February 9, 2013

Trees of the Southern Rainforests

I’ve been promising my fellow blogger over at “My Botanical Garden” a guest post for some time now.  Tamara kindly nominated the Beagle Project for several blogging awards – including most recently the 2012 Blog of the Year Award. My next three installments – some botanical musing on the natural “botanical gardens” of Tierra del Fuego – were inspired by our email conversations – thanks Tamara!

As the weekend began, Darwin’s diary simple states that, “The ship remained in Goree Sound.” (Feb 8/9) – the body of water located near the eastern mouth of the Beagle Channel. So I thought I’d take a couple of days to comment on a few of the plants (and fungi) Darwin’s described in his Zoological Notebook early in 1833.

Finding detailed information about the vegetation of Tierra del Fuego is a little tricky when working in such a remote region. However, with a few resources from my friendly neighborhood botanist and Darwin’s notebooks, I was able to put together a short summary of my own.  First off, Tierra del Fuego seems to be dominated by four major biogeographic zones – (1) the eastern steppes (the southern extension of the Pampas to the north), (2) the alpine regions (mostly in the southwest), (3) the western rainforests, and (4) the “moorlands” or peat bogs in the south. As Darwin is currently in the area dominated by the later 2 bioregions, I’m going to concentrate on those in my next couple of posts.

The western rainforests are dominated by the Southern Beech tree (Nothofagus). There are 36 species of Nothofagus found in the southern hemisphere (in South America, as well as New Zealand, Australia, Papua New Guinea, and several smaller southern islands). Sources suggest that 10 of these species are found in South America, but by the time you reach the cool temperatures of Tierra del Fuego, you can only find three – Antarctic beech (Nothofagus antarctica), Lenga beech (Nothofagus pumilio) and Megellan’s beech (Nothofagus betuloides).

Magellan’s beech (image by Sydney Parkinson from a sample collected by Cook’s expedition in 1769 – from Wikipedia Commons)

Magellan's beech

Lenga beech (from Wikipedia Commons)

Lenga beech

In addition, the botanically-minded traveler can also find winter’s bark (Drimys winteri), Magellan’s mayten (Maytenus magellanica), and a member of the cypress family called pilgerodendron (Pilgerodendron uviferum) growing in the forests. Winter’s bark has been known for some time. Early sailors, including those on Magellan’s and Cook’s expeditions in the 1500’s and 1700’s respectively, knew about the plant and ate the bark (or steeped it into a tea) to prevent scurvy. (Scurvy is a painful ailment caused by a lack of ascorbic acid – a form of vitamin C. It plagued sailors for many years until they realized they could fend it off with vitamin C. Presumably, winter’s bark contains ascorbic acid.)

Winter’s bark, Magellan’s mayten and pilgerodendron (modified from Wikipedia Commons)

Winter's bark, Magellan's mayten and Pilgerodendron

Darwin sums these up this vegetation in Voyage (though remember that was written after returning home and  he blends all his visits to Tierra del Fuego together into a single description):

“I have already mentioned the sombre and dull character of the evergreen forests, in which two or three species of trees grow, to the exclusion of all others. Above the forest land, there are many dwarf alpine plants, which all spring from the mass of peat, and help to compose it: these plants are very remarkable from their close alliance with the species growing on the mountains of Europe, though so many thousand miles distant. The central part of Tierra del Fuego, where the clay-slate formation occurs, is most favourable to the growth of trees; on the outer coast the poorer granitic soil, and a situation more exposed to the violent winds, do not allow of their attaining any great size. Near Port Famine I have seen more large trees than anywhere else: I measured a Winter’s Bark which was four feet six inches in girth, and several of the beech were as much as thirteen feet. Captain King also mentions a beech which was seven feet in diameter seventeen feet above the roots. ” (Voyage of the Beagle)

Tomorrow, Darwin eats some fungus… (RJV)

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Responses

  1. Reblogged this on My Botanical Garden and commented:
    I am happily introducing my dear blogging friend Rob Viens ,https://beagleproject.wordpress.com/,who was kind enough to accept my invitation to become a contributing author for My Botanical Garden. I’ve learned so much from his travel with Darwin! Thank you, Rob , for giving my readers the opportunity to sail new horizons!


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