This is classic Chagga agroforestry, otherwise known as the homegarden. I've probably talked about this before. The grass in the foreground is cut for feed for goats and cows. You can also see yet another one of those planted trees popping up in the open gap in the grass. There are other small seedlings just like this to the left and right of photo and all along this hedge. In the background you can clearly see the multi-level nature of the garden, some very tall trees, and a middle layer of smaller trees, a lower layer of shrub like trees (coffee in this case), and then some smaller plants at ground level. The idea is that everything is working together, making the best use of light and space at all levels. Underground as well, the picture would be similar if we could see the rooting zones of the various plants. They would also be making good use of the moisture and nutrients available by drawing from different depths in the soil. This system in a sense is trying to mimic nature. Not a perfect mimicry though, since many of the species you see are actually not native. The top level, the acacias and other large trees are most likely native. And the grass is native. However, a lot of the other species have been introduced at some point. Coffee came from Ethiopia hundreds of years ago. Avocado as well, and the wild cassava trees you see in the middle were also probably introduced by Portuguese traders 500 or more years ago. Banana is also not native, although apparently archaeological evidence indicates that it may have been here for 1000's of years. I would say that probably about one third of the species  you  see in this photo are native,  and the remaining 2/3's while mostly naturalized and viewed by many as local plants, are strictly speaking from far-flung foreign lands.