make fast saplings respect nodes there growing on

node_defs.lua

@@ -479,9 +479,8 @@ for i in ipairs(moretrees.treelist) do
 		end,
 		on_timer = function(pos, elapsed)
 			if moretrees.can_grow(pos, treename) then
-				minetest.chat_send_all("can grow")
-				minetest.chat_send_all("grow_" .. treename)
 				--moretrees["grow_" .. treename](pos)
+				minetest.set_node(pos, {name="air"})
 				if type(moretrees["spawn_" .. treename .. "_object"])=="string" then
 					local split = moretrees["spawn_" .. treename .. "_object"]:split(".")
 					moretrees[split[2]](pos)

saplings.lua

@@ -40,8 +40,24 @@ local sand_surfaces = {
 }
 
 function moretrees.can_grow(pos, treename)
-	minetest.chat_send_all(treename)
-	return true
+	local surfaces
+
+	if treename == "spruce"
+	  or treename == "fir"
+	  or treename == "cedar"
+	  or treename == "pine" then
+		surfaces = conifer_surfaces
+	elseif string.find(treename, "palm") then
+		surfaces = sand_surfaces
+	else
+		surfaces = dirt_surfaces
+	end
+
+	if surfaces[minetest.get_node(vector.new(pos.x, pos.y-1, pos.z)).name] then
+		return true
+	else
+		return false
+	end
 end
 
 --[[ for i in ipairs(moretrees.treelist) do