IN the Sierra Nevada, there are Whitebark Pines, Pinus albicaulis, thought to be thousands of years old now growing at an altitude where seedlings can’t survive winter. So, they reproduce from suckers. Larry Fields told us the story earlier this week.
On the Eyre Peninsula, South Australia, there are Black Oaks, Allocasuarina cristata, also growing near the limit of their range but because of a lack of water, rather than cold. These trees also reproduce by suckering.
Helen Mahr explains:
I HAVE a large clump of male Allocasuarina cristata trees north of my house, about 1 hectare in area suckering from roots. Also known as Belah or Black Oaks the wind whistles or whines through them and while they are excellent shelter, the noise means the aborigines would never camp there … scared of the ancestor spirits at night.
Outlying suckers, shown in the above photograph with the root they are growing from party exposed, are perhaps 20 metres from the main clump. They have perhaps doubled in size during the 40 years I have been watching them.
The main clump may be thousands of years old.
There are a few female trees scattered in the vicinity, the nearest about 1 km away.
I understand the seedlings germinate only in good years, and may need several good rainfall seasons to establish.
Eyre Peninsula, South Australia
Notes and Links
White Bark Pine Trees: A Note on Climate Change from Larry Fields
Photographs taken by Helen Mahr today, August 13, 2009.
The second photograph shows a Black Oak on the edge of the clump – affected by the SSE prevailing wind. Nearby the prickly wattles, Acaia victoriae, is in bloom. The green shrubby tree in the middle distance is a false sandalwood, Myoporum platycarpum… also called native apricot because of its fruit which is not edible.
The third photograph includes my car as a size indicator of these hardy, fire resistant, and ancient trees.