1. I have a sissoo that grows kind of sideways. The trunk is straight for 10 feet or so, bends to the side (away from a large Shamel ash to its south; I think it was looking for light), and then straightens again. So basically the canopy is 75% on the north side of the trunk. I know you're supposed to put your emitters at the dripline. Does this literally mean *at the dripline* if it's skewed like that? Or should the drippers simply form a circle, the same diameter as the canopy, with the trunk in the middle?

2. Same sissoo is on the side of a dry stream -- a slope. Water from the uphill emitters wants to run downhill, obviously. They're not gushing, they're providing the correct amount/rate of water for flat ground. This is the possibly silly question: should I build a 12" or so basin around the emitter to corral the water and let it soak in where it's supposed to? I don't know enough about the physics of water in soil to know whether that will do any good.

Thank you as always for the help!

However, just because it grows in more in one direction, I don't think it means that most of the roots go that way. The roots go wherever they can find water and nutrients.
I think if you put the emitters spaced evenly in a circle around the tree, the roots will find that water .
I also think that it would be a good idea to do something to help the water go where it is needed instead of letting it all flow to one side. I think the basin under the dripper to keep the water from flowing downhill is a good idea, but I hope that by saying 12" you're not talking about the depth. You shouldn't need more than a couple of inches deep). How fast does this thing drip?

If the water is actually flowing downhill and not going into the soil directly near the dripper, then yes you should create a basin to catch the water. Otherwise, most of the water will be concentrated near the bottom of the slope and the roots may have trouble getting water.

Good luck!

Jeff