I don't know much about Marx, thanks for your info.
But was Marx really so fixated on labor as to think that is the only way value is added?
Obviously a mature tree is far more valuable than a seed, and in nature, no labor is involved in the planting of a seed, nor in the growing of it into a mature tree, but for sure nature is adding massive value by giving us trees.
Did Marx really not attribute any added value to nature, or might he perhaps have included the creative action of nature, in his definition of "labor"?