Quote:
Originally Posted by freeztar  A diviner eh?
I'll assume that the ridge line is on the south side of the higher elevation feature. Water can be found in the desert on the shaded side of geologic features. Sometimes a depth of 6 feet is all that is necessary to provide sustenance. Hence, the trees love the available (and relatively shallow) water suppy.
I'm searching my mind for such a tree and cannot think of one example. Tree roots are advantageously horizontal rather than vertical (for stability and balance). Hence, a 50' tall tree could have roots down to a depth of only 25', but with a breadth of 60' (some trees can and do extend way further than 25', but I'm just throwing numbers out there for example). Perhaps this is confused with the often assumed "50% above, 50% below". An even distribution of mass is a much more likely situation compared to vertical symmetry along the horizon. |
Hi,
different trees have different types of roots. Some have deep tap roots, like Faidherbia albida, reaching down fifty meters and more, other trees have rather shallow root systems, some have a combination of both, like Pongamia pinnata (karanj in India), whose roots dive down ten meters (thirty feet) and spread out sideways twenty meters, just to get hold of every molecule of water and minerals (I avoid the misleading word "nutrients").
The ideal combination is intercropping of all types of root systems.
A good example (not trees) is time-staged planting of Stylosanthes (Campo Grande) and six weeks later of Xaraés (Brachiaria brizantha) on degraded pastures in the Cerrado of Brazil.
Stylosanthes has deep tap roots and grows very fast, while Xaraés has shallow roots (one foot) and grows to five feet above ground within six weeks or so. And this intercropping system stays lush and green even during the usual five month drought period there. So no fires to reset vegetation to almost zero every year. Plus an increase of cattle production (fourfold or more per hectare) with ever increasing fertility of the soil. See at managingwholes.net or do a search for ley farming at the site of Keith Addison. It works!
And planting Malva silvestris together with berry bushes used to be standard a few decades ago, almost forgotten now.
And in Brazil they import Centrosema pubescens from Australia because this plant takes up moisture from the air and transports the water down into the root zone, see under "hydraulic redistribution".
This effect had been discovered around 1925 on a rubber tree plantation in Java by van der Meulen, but again almost forgotten. And Pueraria phaseoloides (Pueraria javanica) can do the same thing. Not to be mixed up with Pueraria lobata, well known in the USA as kudzu. Different plant!
There is lots of knowledge in this world, and the internet can help to spread this info globally and very fast. Thanks to Basic English or even Pidgin. If only more people would care to use the botanical names (sort of Greek Latin).
Today I spent half an hour to find out that the Kachere tree from Malawi is Ficus natalensis. Very useful tree there.
diazotrophicus
Re: Trees and water 
