in forests that are logged/clearcut, when they start regrowing, first to come back is alders, a fast growing hardwood. Heavy nitrogen in their leaves. After a couple of decades, the soil is loaded with nitrogen, then pines start heavy. The pines acidify the soil, which, starts fir. The firs grow, the pines choke out the alders, the firs eventually build a canopy over the pines.
ready to log again.
apparently, the cycle takes about 70 years.
when you mentioned 'symbiotic relationship', it made me think of this.