Do not make orchard in biomes where there is no grass. But on desert... if you channel 1-z level... I have observed grass growing, so even if the trees don't spawn in, you get a small pasture to sustain your animals until the cavern is breached for the fungus spores to spread.
That being said, enjoy the guide, hope it helps you in any way possible.



better than typing it all out, I made a few simple illustrations for easier understanding.

Now these are the steps to be followed to create a proper gather zone.


Here we can see how to set up a basic zone for gathering. You need stepladders and you can customize the zones as per your need. Pretty easy to set up. Complex to customize as per your desire. It can be compounded with custom stockpiles and all and brewing for custom taverns and all. Those are pretty advanced concepts that we don't use here.

An example of dwarves gathering stuff:






An example of dwarves using step ladders to gather fruit 1-z high level on a tree. This is my orchard and pen-pasture compounded with a farming zone in the wall. So like, my farms are a bit safe. Now this is 1-z level high to view the wall. These take time and patience, but once excecuted, saves a lot of dwarf time to do productive stuff and a reliable food source and pasture.

This section will be updated as per needed.







Update 1 :
The concept for high trees updated here :\

Thank you for reading <3