That’s not a lot of wood for 120 days. This fungus is trying to maximize its chances by reaching out as far as it can to find more wood before it dies of starvation. Away from where it has already searched.
Things get more confusing when I talk about how fungi are the original farmers. But I don’t mean that anthropomorphically. I just mean farmer as “an entity that farms”
Susanne Simard, who knows trees better than fungi, tries to ascribe a sense of fairness to how forest food web fungi share and disburse minerals, sugars and water. Personally I just see osmotic pressure. Not as the only driver (see also arbitrage), but the one responsible for most of that “fairness”.
1: https://www.researchgate.net/profile/Emanuel-Goncalves-3/pub...
https://en.m.wikipedia.org/wiki/Turing_pattern
> ... arises due to the interplay between differential diffusion (i.e., different values of diffusion coefficients) of chemical species and chemical reaction.
Meanwhile if you prune the apical bud to try to keep the tree small, it will just elect another leader and keep growing on a side branch.
I have a tree in my yard that got nibbled by insects when it was chest high. Killed the crown bud but not its two siblings. One of them won, then stood up straight and two years later you can barely tell.