Need help with sapling

Hi there everyone, so I am making a custom tree for my mod and I followed the growable sapling tutorial by NorthWestTrees Gaming. The procedures compiled fine and I think I did everything fine, the sapling item places the block on the ground as the tutorial says it should, but the sapling never grows. I suspect I formatted the "modidRandomGrowChance" part wrong. The way I set it was "Sakurasapling1". If someone could help explain that part and if I had formatted it wrong and how to format it, it would be greatly appreciated! Thanks a bunch!