How to space fruit, top storey and nitrogen fixing tree trees

  I think Sepp Holzer has uses tall trees to create micro climates, such as, as a screen north of his ponds to catch the sun and reflect it back onto the pond, or as a wind break, otherwise it seems to be  a row of high trees and then a row of  normal trees and then smaller ones and then bushes and then low plants till you get to the ground and then start to climb back up again. I feel as if it would help me to hear a lot of discusion on this topic. What about how to space them in a small garden, for example. agri rose macaskie. 

In the north temperate regions, the sun will always be south of you.  And within that region, most cold winds come from the north.  Trees planted to the north will act as accumulators of the sun's warmth, as well as buffering the cold north winds as this picture will illustrate:

Illustration from http://www.ag.ndsu.edu/pubs/plantsci/trees/f1055w.htm article on windbreak design.
Worth a read if you are in a windy zone (and North Dakota is known for cold winter winds)!

My plan is to dot taller trees (Honey Locust) throughout the garden to provide light shade which is extremely helpful in this hot climate.  I notice in my existing garden the parts that are doing the best are those that get light shade or afternoon shade.  Full sun areas tend to wilt.  Honey Locust leaf out late so they won't cast shade in early spring when more sun might be helpful.

 Here in spain the villagers at least those in one village i know in Gredos hate trees they think they bring bad weather when in fact they shelter us from bad weather from heat and cold. I read a bit of writing that says they reduce aircondicioning bills in summer in towns. I also read that a climber on your house reduces heating bills.
 What bothers me about permaulture and upper storey trees in how much it will matter if they block out the sun. If you have a small farms there is room for a progresion from high trees to low ones and a space in the midldle for sunloving vegetables and gramineas like wheat but how is one to arrange things in a smaller space i suppose big trees can be planted north of the garden. One or two big trees south of it mean a shade that moves as the sun moves round the tree, so that plants in a climate with a fierce sun like Spain are not exposed to the sun all day.
    H Ludi tyler has in part answered my question while i was writing this. How far apart do you plan to dot your trees.
  I do know of a tradition for combining  trees and grassland in the south of spain, in las Pedroches Cordova, famouse for its hams  and i know of their answer to making sure the evergreen oaks don't over shade the pastures, they cut a branch off their oak trees if they are shading the ground too much. In other bits of spain where oaks are combined with pasture and grain growth the number of oaks a hectare is much less and they don't do this.
 How well do apples for example grow in the shade? The truth is the sun is so high in summer here that is seems hard to get shade. Who has experience, like in california, of growing orchard trees in the shade. California is probably south of Madrid, things are so different in America from europe, the deserts seem to be west east in norht america not North South. Madrid is as far south as New York.
  Geof Lawson planted more nitrogen fixing trees than  fruit baring ones in his greening the desert project or moren nom¡en fruit baring ones, proposis cineraria, a nitrogen fixing tree gives forage and edible beans if i remember right. That is a lot of big trees if locust is your nitrogen fixing tree. rose macaskie.

I am originally from California, and have wandered many of the orchards.  Other than the fruit trees, there is not a tree to be found.  "Shade trees?  We want fruit, not shade!" is the philosophy.  The sad fact is that many orchards have eliminated even the ground cover where the natural pollinators and predators of pests used to live.

The only example I know of a fruit tree that thrives in the shade is the Pawpaw.  They are normally planted as an under storey tree, as they will not do well in full sun, especially in their native hot & humid south.

I'll probably put the Honey Locusts about 20 feet apart.

One way to tell if an area is getting enough sun to grow vegetables is if grass will grow there.  If no grass grows under a tree, it is casting too much shade for most vegetables.

Dont honey locusts grow to nearly 70 feet tall and cover about the same? Do you plan on thinning the locust at some point in the future?

trees and plants should be spaced depending on which species they are. and if they are dwarfed in the case of grafting. know your trees and you will know how far to space them.

Honey Locusts don't grow that tall here. 

The honey locusts in my area may get 70' tall but in no way are they 70' across. More like 20'. They are also fairly sparse. Just my data point.