A part of my land is a pine monoculture, approximately 20 years old. I would like to introduce more biodiversity into it, by graduallly thinning it and planting other trees and shrubs native to the area but not present on my land - oaks, black and honey locusts for n-fixing, hawthorns, blackberries and many others, but due to a scale I would prefer to use seeds rather than seedlings. I'm sure all of you have heard stories about the man that has planted the forest, like this one:
This is something I would like to replicate. I'm on a very sandy soil, I have been trying different methods, and basically nothing works. I have tried seedballs (Fukuoka style) and seeds of species that "grow everywhere" yet still I have only pines. I'm starting from the edge facing south, so I'm sure there is enough light for the new plants if only they grow from seeds. I'm in zone 6 by the way, so many species need stratification, therefore I have tried planting seeds in Autumn as well. Providing that I have plenty of seeds, what would be the best method to plant them if we assume that we are planting in the final location for the particular tree and that it is not going to be ever moved? Is this possible at all to achieve my goal without establishing tree nursery?