The stump acts as a biological cistern for the neighboring trees. In return for nutrients, it stores water when demand is low (night) and supplies water when d

The stump acts as a biological cistern for the neighboring trees. In return for nutrients, it stores water when demand is low (night) and supplies water when demand is high (day). I imagine that the main survival advantage is that the neighboring trees get to grow leaves and branches into the stump's canopy void much faster than if they had to expand their own root system. This should give the trees a big advantage over other nearby species competing for the newly available sunlight.