Bryant RedHawk wrote:Most of the top 10 feet of the Sierra Nevada mountain range is fractured granite, roots can get into the fractures and they will continue to widen those fracture lines.
Now, if you are wanting to use a lot of fuel and effort, then what you are doing would be worthwhile except that making hugel mounds is not how to plant trees, the hugel will eventually collapse and the tree will topple.
When you want to plant a tree, you want a stable surface, not something that is bound to collapse. If you really want that extra two feet for the roots, you will need to use stone and mortar to build giant "tubs" for each tree to live in. A lot of work indeed.
Why not simply use the land as it is, plant the trees and keep them watered until they have established nicely at that point they will have roots anchored into the granite bed rock and you are good to go.
More important than the soil depth is what is living in that soil, all the trees you mention require mycorrhizae to flourish, so make sure your tree's roots have access to these fungi and then add a compost mulch to prevent moisture loss and add organic matter to the soil.
By the way, granite soils tend to be acidic, so do get that tested or buy a kit and do it yourself so you know the starting base line then you can check it yearly to see how things are changing.
He does not suffer fools gladly. But this tiny ad does:
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