diff --git a/mods/core/drop.lua b/mods/core/drop.lua
index bff330c..ec1b090 100644
--- a/mods/core/drop.lua
+++ b/mods/core/drop.lua
@@ -31,7 +31,7 @@ function minetest.handle_node_drops(pos, drops, digger)
 	end
 	if minetest.get_node_group(minetest.env:get_node(pos).name, "drop_on_dig") == 1 then
 		drop_all()
-	elseif digger:get_inventory() then
+	elseif digger and digger:get_inventory() then
 		for _, dropped_item in ipairs(drops) do
 			if digger:get_inventory():room_for_item("main", dropped_item) then
 				digger:get_inventory():add_item("main", dropped_item)
@@ -39,5 +39,7 @@ function minetest.handle_node_drops(pos, drops, digger)
 				drop(dropped_item)
 			end
 		end
+	else
+		drop_all()
 	end
 end
diff --git a/mods/core/falling.lua b/mods/core/falling.lua
index afbcd24..54fc1d0 100644
--- a/mods/core/falling.lua
+++ b/mods/core/falling.lua
@@ -1,31 +1,53 @@
+function minetest.register_node(name, nodedef)
+	nodedef.type = "node"
+	if not nodedef.cause_drop then
+		nodedef.cause_drop = function(pos, node)
+			local b_pos = {x=pos.x,y=pos.y-1,z=pos.z}
+			local b_node = minetest.env:get_node(b_pos)
+			if minetest.registered_nodes[b_node.name].walkable == false then
+				return true
+			end
+		end
+	end
+	if not nodedef.cause_fall then
+		nodedef.cause_fall = function(pos, node)
+			local b_pos = {x=pos.x,y=pos.y-1,z=pos.z}
+			local b_node = minetest.env:get_node(b_pos)
+			if minetest.registered_nodes[b_node.name].walkable == false then
+				return true
+			end
+		end
+	end
+	minetest.register_item(name, nodedef)
+end
+
 function nodeupdate_single(p)
 	n = minetest.env:get_node(p)
 	if minetest.get_node_group(n.name, "falling_node") ~= 0 then
-		p_bottom = {x=p.x, y=p.y-1, z=p.z}
-		n_bottom = minetest.env:get_node(p_bottom)
-		-- Note: walkable is in the node definition, not in item groups
-		if minetest.registered_nodes[n_bottom.name] and
-				not minetest.registered_nodes[n_bottom.name].walkable then
-			minetest.env:remove_node(p)
-			spawn_falling_node(p, n.name)
+		if minetest.registered_nodes[n.name].cause_fall(p, n) then
+			if minetest.registered_nodes[n.name].on_falling then
+				minetest.registered_nodes[n.name].on_falling(p, n)
+			else
+				minetest.env:remove_node(p)
+				spawn_falling_node(p, n.name)
+			end
 			nodeupdate(p)
 		end
 	end
 	if minetest.get_node_group(n.name, "dropping_node") ~= 0 then
-		p_bottom = {x=p.x, y=p.y-1, z=p.z}
-		n_bottom = minetest.env:get_node(p_bottom)
-		if not minetest.registered_nodes[n_bottom.name].walkable and n_bottom.name ~= n.name then
-			if not minetest.registered_nodes[n.name].drop_on_dropping then
-				minetest.env:dig_node(p)
+		if minetest.registered_nodes[n.name].cause_drop(p, n) then
+			local meta = minetest.env:get_meta(p)
+			if minetest.registered_nodes[n.name].on_dropping then
+				minetest.registered_nodes[n.name].on_dropping(p, n)
 			else
+				local drops = minetest.registered_nodes[n.name].drop_on_dropping or
+					minetest.registered_nodes[n.name].drop or n.name
+				if type(drops) == "string" then drops = {drops} end
 				minetest.env:remove_node(p)
-				local stack = ItemStack(minetest.registered_nodes[n.name].drop_on_dropping)
-				for i = 1,stack:get_count() do
-					local obj = minetest.env:add_item(p, stack:get_name())
-					local x = math.random(-5,5)
-					local z = math.random(-5,5)
-					obj:setvelocity({x=1/x, y=obj:getvelocity().y, z=1/z})
-				end
+				minetest.handle_node_drops(p, drops)
+			end
+			if minetest.registered_nodes[n.name].after_dig_node then
+				minetest.registered_nodes[n.name].after_dig_node(p, n, meta, nil)
 			end
 			nodeupdate(p)
 		end
diff --git a/mods/default/init.lua b/mods/default/init.lua
index e7b7905..f54c5be 100644
--- a/mods/default/init.lua
+++ b/mods/default/init.lua
@@ -441,6 +441,13 @@ minetest.register_node("default:papyrus", {
 	walkable = false,
 	groups = {snappy=3,flammable=2, dropping_node=1,drop_on_dig=1},
 	sounds = default.node_sound_leaves_defaults(),
+	cause_drop = function(pos, node)
+		local b_pos = {x=pos.x,y=pos.y-1,z=pos.z}
+		local b_node = minetest.env:get_node(b_pos)
+		if b_node.name ~= node.name and minetest.registered_nodes[b_node.name].walkable == false then
+			return true
+		end
+	end
 })
 
 minetest.register_node("default:glass", {
@@ -662,6 +669,7 @@ minetest.register_node("default:cobble_node", {
 	},
 	drop = "default:cobble",
 	groups = {dig_immediate=2,dropping_node=1,drop_on_dig=1},
+	buildable_to = true,
 	sounds = default.node_sound_stone_defaults(),
 })
 
diff --git a/mods/trees/init.lua b/mods/trees/init.lua
index 795273d..b4b50dd 100644
--- a/mods/trees/init.lua
+++ b/mods/trees/init.lua
@@ -13,9 +13,10 @@ function trees.make_tree(pos, tree)
 			return
 		end
 	end
-	for i = 0,height do
+	for i = 0,height-1 do
 		minetest.env:add_node({x=pos.x, y=pos.y+i, z=pos.z}, {name=tree.name.."_trunk"})
 	end
+	minetest.env:add_node({x=pos.x, y=pos.y+height, z=pos.z}, {name=tree.name.."_trunk_top"})
 	for i = 1,#tree.leaves do
 		local p = {x=pos.x+tree.leaves[i][1], y=pos.y+height+tree.leaves[i][2], z=pos.z+tree.leaves[i][3]}
 		if minetest.env:get_node(p).name == "air" or minetest.env:get_node(p).name == "ignore" then
diff --git a/mods/trees/registration.lua b/mods/trees/registration.lua
index bff5f14..059519b 100644
--- a/mods/trees/registration.lua
+++ b/mods/trees/registration.lua
@@ -180,6 +180,27 @@ function realtest.register_tree(name, TreeDef)
 				{-0.4,-0.5,-0.4,0.4,0.5,0.4},
 			},
 		},
+	})
+	
+	minetest.register_node(tree.name.."_trunk_top", {
+		tiles = tree.textures.trunk,
+		groups = {tree=1,snappy=1,choppy=2,flammable=2,dropping_node=1,drop_on_dig=1},
+		sounds = default.node_sound_wood_defaults(),
+		drop = tree.name.."_log",
+		drawtype = "nodebox",
+		paramtype = "light",
+		node_box = {
+			type = "fixed",
+			fixed = {
+				{-0.4,-0.5,-0.4,0.4,0.5,0.4},
+			},
+		},
+		selection_box = {
+			type = "fixed",
+			fixed = {
+				{-0.4,-0.5,-0.4,0.4,0.5,0.4},
+			},
+		},
 		after_dig_node = function(pos, oldnode, oldmetadata, digger)
 			for i = 1,#tree.leaves do
 				local p = {x=pos.x+tree.leaves[i][1], y=pos.y+tree.leaves[i][2], z=pos.z+tree.leaves[i][3]}