The Acacia is one of the few indigenous trees that survives in the harsh conditions of the Arava region of southern Israel. With global warming accelerating, some environmentalists have voiced concern that acacia stands are drying up. However almost no research is being done on natural regrowth.
Two species of acacia grow naturally in the Arava wadis: the Acacia tortilis and Acacia raddiana. A third, the Acacia negevensis grows only in the higher altitudes of the Negev mountains. Typically these trees will grow along the edges or on the banks of small wadis, where they won’t be disturbed by flash floods. And we often see groves of trees that seem to be about the same age. Acacias are photo-synthetically active all year, do not loose their leaves, and thus there is no banding in the trunk. So it’s hard to determine the actual age of a particular tree. But from roughly estimating the uniformity of the trees’ heights, diameter of the trunks, number of main branches, it seems that stands of acacia appear as a result of a particular climatic event which most likely included a suitable combination of rainfall and temperature to allow many new seedlings to sprout at the same time and survive.
The questions that come to my mind are “What are those ideal conditions for natural regrowth?” and “Where can we find new generations of acacias?”. As for the required conditions, I don’t know, yet, but I have found some spots where new seedlings have sprouted and are surviving. In fact, in one such spot I located three new seedlings within a 100 m. stretch of a small wadi. And, interestingly, one was growing right at the feet of a grand-daddy tree that had fallen victim to old age. An unusual, but perhaps encouraging happenstance…
I chose one of the new seedlings as our “Family acacia” and I’ll try to follow its growth over the years. So here’s our start:
|Date||Canopy Diameter||Height||Trunk diameter||Longitude||Latitude||Elevation|
|22/04/2011||0.58 m||0.22 m||0.014 m||35d10'18.533"E||30d47'33.321"N||-40 m|
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