I was hoping to get some help with suntrap design.
I've read up on the basic theory online and in Mollisons Permaculture Designers Manual but have found no specific information on dimensions, and how to plot/measure it out other than having it curve from east to north to west. I understand that a good windbreak loses effectiveness at an average of 200' in width, but thats all I have to go on.
How did you go about ensuring proper angle of the curve? Assuming that you did... What was the length of your east to west line? and what was the length of your south to north line?
I have a large hay field of approximately 450' X 850' that I'd like to completely convert to suntraps. One hitch is that the hill slopes gently (some areas are completely level) from south to north-ish, so I could see a problem with frost getting caught by the northern edge of the windbreaks. But then again, maybe that means I have to put the more frost tolerant species in the southern-most traps, and the tender ones in mid-slope? Or do I have this backwards? Maybe I should forgo the suntrap idea and just create north-south running windbreaks that are continuous from north to south? (with openings for machinery to get through of course)
We have just planted a very steep slope with trees and shrubs that used the sun-trap method, by accident. I had most of it already planted and used common sense in planning it. I had ordered Toby Hemenway's "Gaia's Garden, and was very happy when it arrived and the concept was explained in the book. I had realized I had done the exact same thing already.
We have a southern exposure on the slope. Actually, somewhat of a south to south-east exposure. I looked at where the sun tracked and figured putting the tallest plants on the northern top of the slope was a good idea. The key is, you are creating a bowl shape to allow all of the plants to get the most hours of available sunlight on them. We had to take into consideration the steep angle of the slope, and its microclimates, which I had not known about before reading the book. So we will see after the plantings mature whether or not it was done correctly. The last of the plantings (after reading the book) were the Apple trees (semi dwarf) and they were planted closer to the bottom as they could take a colder spell more easily. Also, the tree heights are mitigated by the drop of the slope.
Just look at the sun's daily movement and plant as close to that arc as you can. It will not be perfect anyway, as the angle of the sun's movement will change during the summer, but you will be close enough.
Our house acts the windbreak and that I can't change, as far as length or height, so if it offers wind turbulence there is not much I can do.
If you use the basic formula and get most of it right, I can't see you having any problems. It certainly has to be better than just guessing where to plant.
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