The Tree tribe is unlike the Human Race; there's no issue of kinship sentiment.
Plants need sunlight and water to grow. These natural resources are needed by the Tree tribe, leading to competition.
Take the example of the Redwood Spirit that Feng Jun killed. It wanted to monopolize these resources and controlled its subordinate Redwoods, forbidding them from advancing to the Golden Core.
As for the relationships between different tree species, these might be worse than their relationships with the Human Race.
The Tree tribe has never been a unified group, completely different from the Human Race. Although internal conflicts among humans are not uncommon, they generally can unite against foreign threats—at least there's this concept.
The Tree tribe lacks even the concept of uniting against outsiders. That's why the Wood User doesn't mind dealing with the Lingmu Sect.
