posted 9 years ago
Hi Adam, All tree roots in the temperate zones are mostly near the surface - 50% or more in the top 12-18 inches. They all have to "duke it out" in the shallower soils. Only 2% of all trees have taproots, so depth is not the issue. I have a drawing where the apple roots of one tree seem to be growing away from another apple tree. This is confusing as prosperous apple orchards are all over the county I live in. I don't know of any case were different species of tree roots avoid each other. But there are plants with allelopathic chemicals that stunt the growth of other plants - examples include marigolds, walnut trees, elderberry stunts grasses, buckwheat stunts weeds. etc. See the list in my appendix.
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