I can think of good experience in both models. I have always been wary of regular spacing woods (planting trees following mechanization-boosting patterns, so planting for the easiness of maintenance, that many landscape architects opt for in their designs), as I tend to think of a wood as a "natural" thing, that gets more dense here and less dense there according to the site (following geological, climatic, animal presence and other factors), some trees propagate themselves in packed form while others in a more loose manner. But the regular pattern of 3x4, 4x4 or 5x5 are just weird for me. Too strict, too much designed.
There was someone that emailed me, very concerned, before giving his vote to Fruta à mão (the project under vote in the Participatory Budget). He wanted to be sure the park wasn't going to be turned into a high-production-like orchard, I told him I disliked regular plantations and did not want to create such an orchard. However, now I could see Gaetano's point. One thing is a productive orchard, another is a forest, another is a garden with fruits... Hum. How to solve this?
I would say that the point of the our orchard is not to just add a few trees with fruits, but to create an impact that demonstrates the potential of fruit in the city, and that exemplifies that productive trees are just as beautiful as ornamental ones, contributing for the aesthetic experience of the city along with providing food (and remembering urbanites that not all food need to be bought, that we can turn our public space into a commons. What is then the best way to do it, with a garden with fruits or with an "orchard-orchard"? Should we be planting along a defined form, like a spiral? Put as many trees as possible, but not be precise with their distances?
Those questions will be debated on our round table at the orchard, on June 14th. Come along, share your thoughts!!