When you plant a large cactus seedling atop a single piece of sand, the sand will be pulverized once the cactus grows.
You mean the sand is replaced by a cactus node? ~That's expected, just like a tree, it's the cactus root.~
Trees don't, and should not do that. This breaks farms and destroys sand in the process, its bad behavior.
Sorry, i see. Sapling-grown trees only force-place the node that replaces the sapling, i forgot, was thinking about mapgen trees. Large cactus should do the same. Will fix.
https://github.com/minetest/minetest_game/blob/61bfac0fa201253fa1327f7eba1e81445bed5583/schematic_tables.txt#L2046
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Trees don't, and should not do that. This breaks farms and destroys sand in the process, its bad behavior.