I have read a lot about tree guilds from various sources (Edible Forest Gardens, Gaia's Garden, Martin Crawford Forest garden books...).
Books describe guilds (including nice sketches) around adult tree, where the inner space is filled with insectary or mulch plants and on the outside of crown there are nurse trees (mostly nitrogen fixers).
That was a theory and now I'd like to jump into practice. However I stepped into information vacuum - in the books there is no info how to start a new guild around a newly planted tree. Herbs are OK, they can expand. But what concerns me the most is at what distance to plant the nurse trees. In my opinion the closer the better (in order to have more advantage from fixing nitrogen), but not too close (in order for main tree to be able to expand), so ideally on the drip line. However main tree grows and drip line moves too. And what to do with nurse trees? Cut them every 2-3 years and plant new ones further away? (that sound as a lot of work for permaculture...) Or plant them further away from scratch ? (but they won't work as nurse plants for the first 10-15 years...).
I want to make guilds in the spring around my new small wallnuts. According to several studies (for example http://forestry.oxfordjournals.org/content/81/5/631.abstract), the wallnuts greatly benefit from companion with Elaeagnus Umbellata (autumn olive) resulting in higher growth and yields. However I could not find any info how to start this benefitial relation from the scratch and how to alter this guild when the trees grow and expand during time...
Any hints, own experiences, links to articles or books appreciated!
plant any nitrogen fixers just as Kyrt said. You can coppice them and chop and drop them, and eventually chop them out, all the while they are providing for your choice trees. You can plant one right in the same hole as your choice tree. Don't be fixed on the spacing, if you can get the trees cheap or free. You can space them out afterwards.
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