update recipes.

add recipe for planting nuts with dirt.

change plank recipe into pummeling log with stone.

add (currently unusable) recipe to pummel leaves into dirt.

mods/bg_tree/recipes.lua

@@ -1,4 +1,36 @@
 local modname = minetest.get_current_modname()
 
+-- plant saplings
+-- TODO: when recipes add support for groups, use `dirty` group here instead of specific nodes.
 blockgame.crafting.register_stack_recipe("core:grass", modname .. ":nut", {name = modname .. ":sapling"})
-blockgame.crafting.register_stack_recipe(modname .. ":log", modname .. ":nut", {name = modname .. ":plank"})
+blockgame.crafting.register_stack_recipe("core:dirt", modname .. ":nut", {name = modname .. ":sapling"})
+
+-- NOTE: is currently useless, as there's no way to obtain leaves.
+blockgame.crafting.register_pummel_recipe({
+	label = "pummel leaves into dirt",
+	used_item = modname .. ":leaves",
+	target_node = modname .. ":leaves",
+	on_success = function (pos, used_node, target_node)
+		minetest.set_node(pos, {name = "core:dirt"})
+	end,
+})
+
+blockgame.crafting.register_pummel_recipe({
+	label = "pummel log into plank",
+	used_item = "core:stone",
+	target_node = modname .. ":log",
+	check = function (pos, used_node, target_node)
+		for _, side in pairs(blockgame.vector.sides) do
+			local output_pos = pos + side
+			if minetest.get_node(output_pos).name ~= "air" then return false end
+		end
+		return true
+	end,
+	on_success = function (pos, used_node, target_node)
+		minetest.remove_node(pos)
+		for _, side in pairs(blockgame.vector.sides) do
+			local output_pos = pos + side
+			minetest.set_node(output_pos, {name = modname .. ":plank"})
+		end
+	end,
+})