Mod by Shara RedCat that causes default apples to regrow on trees.
This uses node timers, instead of laggy ABMs, so should be very light to run.
Please note that adding this mod to an existing world can lead to (very minor) item duplication (of a sort) being possible. If you already have any apples and place them, then pick them up, a new apple will reappear in that position between 2 to 5 minutes later. This will only happen once, because all apples collected since the mod was added won't have this problem.
Code for this mod is released under MIT (https://opensource.org/licenses/MIT).