At some point, I saw a video a few years ago that showed the huge fruit someone got from a fruit tree they were peeing on to fertilize it. Unfortunately, I can't readily find that video again.
There are a surprising number of videos, about peeing on trees, some negative but many positive. This guy did a bona-fide experiment comparing a commercial fertilizer with human urine.
The above linked video is over 18 minutes. At the start, he lists multiple websites he checked for info on NPK ratio (nitrogen, phosphorus and potassium) of human urine.
He used pepper plants and lettuce. He also collected his urine and let it sit for a few days, presumably to kill any bacteria because you aren't supposed to use untreated human urine on crops. It can spread disease.
Peeing directly on tree roots is safe. If the tree is a fruiting plant, the tree will process the urine and the fruit will be safe to eat, though if it is a designated tree urinal and many people pee there regularly, you may wish to be careful to not place fruit on the ground while collecting it.
His experiment involved making sure there were no other nutrients available to the plants. So his results are not representative of what would happen with a tree planted in soil.
The plants fertilized with human urine did not thrive. He concluded that human urine lacks micronutrients they need.
His audience is gardeners in developed countries. He acknowledges human urine is, in fact, a fertilizer but concludes it's not as good as the commercial fertilizer he tested it against.
That's not my audience and organic gardening per se is not my goal here.
If you are trying to do development in very underdeveloped areas where open defecation is practiced, tree urinals are a means to cheaply improve hygiene for locals in a manner they can afford and maintain.
If you get enough food and drink to not outright die, you can afford to pee on a tree. If the community is extremely poor, start with designating trees to pee on.
If there are some resources for the project, add a post with hand sanitizer, a spray bottle of salt water or similar to clean up with. If there are additional resources, you may wish to add a privacy wall or privacy enclosure.
Some such places will be areas where food security is an issue as well. Choosing fruit trees for your tree urinals can help grow additional food for the community at no extra cost.
No, human urine doesn't compete with fancy commercial fertilizers for efficacy. But it is better than not fertilizing the plants at all.
Additionally, tree urinals and latrines that use wetlands as waste management will help green the area up, mitigate temperature extremes locally, combat desertification if that's a local issue and start to mitigate global warming.
As high temperatures come down, people will be less thirsty, which will take pressure off scarce resources, and less grumpy, which will reduce interpersonal conflict. If fruit trees are used and people start eating better, that will help further mitigate various issues.
You may need to come up with rules about how to distribute the fruit but that's a better problem to have than starvation.