My trees are planted on a slope. Here is a configuration used, a sub-main valve to control the source water for the slope. From the sub-main valve 2” PVC pipe runs across the slope. From this feeder line multiple 1/2” pvc/poly laterals are laid. Each lateral line covers a set of trees at the same elevation. The feeder/lateral junction is controlled via a Senninger 20psi pressure regulator (
https://www.senninger.com/sites/senninger.hunterindustries.com/files/pressure-regulator-catalog.pdf) along with a shut-off valve. The pressure regulator/shut-off is set off a 3/4” pvc riser.
As for the sprinklers, I use a combination. For mature trees it is the Challenger micro sprinkler (
https://www.philmac.com.au/app/uploads/2018/01/WSS001-Orbitor-Challenger-Specs.pdf). The lowest volume in this series is 14GPH, and one of the features I like about these sprinklers is that the rotation is smooth and the water delivery is consistent with large water droplets. This allows the water to fall within the canopy and is not easily affected by wind. The one drawback is with weeds strangling/blocking the spinning rotor. If the GPH will work, there is an option with the challenger sprinkler to reduce the distribution width by swapping the rotary wing for the detachable dot you see in the picture. With the dot, the water is delivered as an inverted cone. Occasionally I run into clogs primarily due to broken lines/sediments, and it is easy to unclog with a needle by separating the wing.
For young trees I have experimented with a few different options and here are my observations - with the 10 and under GPH rotary spinners the prime concerns were the density of the water delivery and the resulting wind drift. The delivery is more like a spray rather than droplets in these spinners, and at least in my location is easily affected by wind. The few varieties I have tried are similar to the RK12-110 in your picture, and a few others with barb base. I have also tried some bubblers with not much success. An additional problem I encountered with barb base sprinklers was that they easily snapped off the dome fixture and was a hassle to manage.
Recently I started trying 6GPH bowsmith sprinklers (
https://www.bowsmith.com/assets/fanjetmicrosprinkler_performancedata2.pdf), and appears to work well with a few caveats. I especially like that the water delivery is like droplets and is not affected by wind. I encounter a bit of clogs especially in the end laterals, which I suppose can be better managed with some filters. The clean up is a bit tedious compared to the Challenger sprinkler. I think I may be able to alleviate the occasional clogs by switching to a higher capacity. It is likely the orifice of the smallest/black nozzle I currently use is just too small for the sediments to pass through. The default delivery diameter is large for small/young trees, and I have adapted by adding on a hat (
https://www.dripdepot.com/product/bowsmith-top-hat). The hat reduces the delivery diameter by half. This is on 1/4” poly fittings which tends to attract additional work from the squirrels. I have found wrapping the tubing with aluminum foil helps, but I also tend to be less diligent in doing this extra step.
There is this whole world of pressure compensated sprinklers, I have not experimented yet mostly because of the cost differential. I am always on the look out for better sprinklers especially for the young trees. Thanks for all the suggestions so far in this thread, will check them out.