Podzol Grows Old Growth Trees

I was think an interesting idea for giving Podzol a use, is to have Podzol affect the way tree saplings grow. To be more specific, in Minecraft there are different variants of forest biomes, one of those variants are the old growth forest biomes which generally have larger trees than their normal variants. As it currently stands, there is no way to get new tall birch trees without naturally generating more old growth birch forests in Minecraft. So I think it would be nice for there to be a way to create new tall birch trees.

Enter Podzol! Make birch tree saplings planted on Podzol grow into their tall birch tree variants. Podzol could also either increase the chances of, or guarantee that oak tree saplings planted on Podzol grow into their large oak tree variants. Podzol could also affect the growth of other saplings or plants that are planted on Podzol in some way!