"...plots replanted with a mixture of 16 native tree species showed faster recovery of canopy area and total tree biomass, compared to plots replanted with 4 or

"...plots replanted with a mixture of 16 native tree species showed faster recovery of canopy area and total tree biomass, compared to plots replanted with 4 or just 1 species. However, even plots that had been replanted with 1 tree species were recovering more quickly than those left to restore naturally." I am not trying to be obtuse or misanthropic. Please, someone can explain why was this study needed? Was there some hidden new discovery? Asking, because if I walk down the dirt road and ask any farmer, they will tell me, if I sow seed in a field, it will grow faster, than I leave it to nature's chance. If I sow mixed crops (crop & cover crop), I will get potentially better yield. I thought it was a specific species of trees thing, but the paper does not seem to be stating it.