diff --git a/mods/bg_tree/grow_sapling.lua b/mods/bg_tree/grow_sapling.lua
index 048ad11..ffe7336 100644
--- a/mods/bg_tree/grow_sapling.lua
+++ b/mods/bg_tree/grow_sapling.lua
@@ -5,7 +5,6 @@ local modname = minetest.get_current_modname()
 local sapling = modname .. ":sapling"
 local log_alive = modname .. ":log_alive"
 local leaves_growing = modname .. ":leaves_growing"
-local root_alive = modname .. ":root_alive"
 
 -- END OF NODE NAMES
 
@@ -42,11 +41,24 @@ blockgame.register_increasing_abm({
 		-- (this will require the api adding support for increasing_abm actions modifying their data.)
 		local above = pos + blockgame.vector.dirs.up
 
+		-- grow up, with a chance to stop growing.
 		if not blockgame.chance(4) then
 			minetest.set_node(above, {name = sapling})
 		end
-		minetest.set_node(pos, {name = log_alive})
 
+		local below = pos + blockgame.vector.dirs.down
+		-- if this tree have already grown at least once, create a log...
+		if blockgame.item_matches(minetest.get_node(below).name, {
+			modname .. ":root_alive",
+			modname .. ":log_alive",
+		}) then
+			minetest.set_node(pos, {name = log_alive})
+		else
+			-- ... otherwise, create a root
+			minetest.set_node(pos, {name = modname .. ":root_alive"})
+		end
+
+		-- grow out leaves to the sides.
 		local sides = blockgame.vector.get_sides_of(pos)
 		for _, side in pairs(sides) do
 			blockgame.attempt_place(side, {name = leaves_growing})