diff --git a/API.txt b/API.txt
index 217104f..c033926 100644
--- a/API.txt
+++ b/API.txt
@@ -128,6 +128,9 @@ biome = {
 	avoid_radius = num,	-- [*] how much distance to leave between
 				       the object to be added and the objects
 				       to be avoided.
+	rarity = num,		-- how rare should this tree be in its biome?
+				   Larger values more rare, determined by
+				   math.random(1,100) > this
 	seed_diff = num,	-- perlin seed-diff value.  Defaults to 0, 
 				   which causes the function to inherit the
 				   global value of 329.
diff --git a/plants_lib/init.lua b/plants_lib/init.lua
index f43fc31..1e8a54f 100644
--- a/plants_lib/init.lua
+++ b/plants_lib/init.lua
@@ -74,6 +74,7 @@ function plantslib:search_for_surfaces(minp, maxp, biome, funct_or_model)
 			  and noise2 >= biome.temp_max
 			  and (biome.ncount == nil or table.getn(minetest.env:find_nodes_in_area({x=pos.x-1, y=pos.y, z=pos.z-1}, {x=pos.x+1, y=pos.y, z=pos.z+1}, biome.neighbors)) > biome.ncount)
 			  and (biome.near_nodes == nil or table.getn(minetest.env:find_nodes_in_area({x=pos.x-biome.near_nodes_size, y=pos.y-1, z=pos.z-biome.near_nodes_size}, {x=pos.x+biome.near_nodes_size, y=pos.y+1, z=pos.z+biome.near_nodes_size}, biome.near_nodes)) >= biome.near_nodes_count)
+			  and math.random(1,100) > biome.rarity
 			  then
 				table.insert(in_biome_nodes, pos)
 				num_in_biome_nodes = num_in_biome_nodes + 1