A couple of days ago I ran across a question on a message board. What the poster was asking was whether or not Geoff Lawton’s designs that he did in hot, arid areas would work in other places. The short answer is the same one you will get for most questions about Permaculture practices. It depends.
The longer answer is that they will absolutely work anywhere, but you would be better suited to create designs that are more suited to you climate and landscape profile.
The example of this that comes to mind first is using 10-20 leguminous trees (for nitrogen sharing and chop and drop) for every food crop tree in a system and doing extensive chop and drop. In the majority of Mr. Lawton’s designs, he is working in places that have limited top soil. There is also typically a limited amount of rain and the need to use copious amounts of mulch is necessary to keep any moisture in the ground. By contrast in if you are in an area like the central Ohio River Valley where you get an average of 39 inches of evenly distributed rain a year and have deep topsoil as the result of the last ice age, there is much less need to use so many leguminous trees in your system. You will get similar results by using as few as 3-5 per food crop tree, and could even replace them with leguminous shrubs.
Another great example is Huglekultur. If you are in that same Ohio River Valley, with evenly distributed substantial rains, the need for the water conservation and storage that Huglekultur provides is mitigated greatly. It is still a good way of drought proofing your garden, but you can accomplish your goal of producing food with little water input just with small swales and other water harvesting/distribution methods.
This goes on and on, with the desire to use more heat traps in cooler climates, less cool breeze blocking in warmer ones, mulching more in hot dry places and less in cool damp ones. The long and short of this is that while all of the design methods of Permaculture will work most places, it is best to pick the parts that fit you, your climate and your landscape profile. So keep this in mind as you learn what other people are doing, and always ask yourself how their design would fit into your situation.