Monday, March 10, 2014

Larrea digs its own swale

Did I tell you that creosote (larrea tridentata) is amazing?

We were checking the larrea around our property on Saturday and found these strange gouges around the outside of the plant. At first we thought it was critters, but as we sat on the porch the wind kicked up and we noticed the lower branches of the larrea were whipped back and forth over the ground digging what, for all practical purposes, are swales, or water harvesting depressions. When it rains here again, water will pool here and be delivered to the surface roots of the larrea. How cool is that?!


NEW RULE:
Never cut the low hanging branches of larrea tridentata, whether living or dead.

The swales may be why the larrea with a more horizonal growth aspect, with swale-digging branches closer to the ground,  is greener and denser than the larrea with a more vertical growth aspect which is thinner and lacier. In addition, the more horizontal growth collects more detritus - old leaves and branches, animal droppings, and topsoil that the wind blows in, providing more nitrogen to the plant.


There must be a reason for the more vertical growth. Perhaps the more vertical plants thrived in wetter years and provide biodiversity for changes in climate, or served as nurse plants to the more horizontal larrea under/next to them. Whatever the reason, these are amazing, old growth desert woodlands plants that should be afforded respect and protected, and to an extent, they are.

California Desert Native Plants Act 
The California Desert Native Plants Act was passed in 1981 to protect non-listed California desert native plants from unlawful harvesting on both public and privately owned lands. Harvest, transport, sale, or possession of specific native desert plants is prohibited unless a person has a valid permit. The following plants are under the protection of the California Desert Native Plants Act:
- Creosote Rings, ten feet in diameter or greater

We have several creosote (larrea) rings on our property. You have to be careful about determining these, though, as sometimes only a portion of a ring survives, but the curve of the circle could still extrapolate to ten feet or more, making the plants on the curve hundreds, if not thousands, of years old. Cutting them down would be like felling a giant redwood or sequoia.


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