#3 is not about making observations in general but about making a map of every tree. This is a common mistake of scientists, wanting to have a complete set of data on their topic. I myself have to remind myself of this as well when designing projects. But in reality you cannot make a map of every tree and even if you could, what’s it worth? You need abstractions to understand anything and models are just that. To design a good research study you need to balance how many observations are necessary vs how much effort they take.
I feel like it’s just useful for different use cases. You don’t need to start with making a map of all trees everytime but it certainly would be handy if someone else had compiled a map of all / most trees for reference.