Fix swamp trees.

mapgen.lua

@@ -33,7 +33,6 @@ do
 	tree_biomes["taiga"] = {"conifer_trees"}
 	tree_biomes["rainforest"] = {"jungle_trees"}
 	tree_biomes["rainforest_swamp"] = {"jungle_trees"}
-	tree_biomes["deciduous_forest_swamp"] = {"deciduous_trees"}
 	tree_biomes["coniferous_forest"] = {"conifer_trees"}
 
 	for i, obiome in pairs(minetest.registered_biomes) do
@@ -361,7 +360,7 @@ function loud_walking.generate(p_minp, p_maxp, seed)
 					local y = minp.y + get_height(x - minp.x, z - minp.z, biomes[biome].terrain_scale, ocean) + ground
 
 					local ivm = a:index(x, y, z)
-					if data[ivm + a.ystride] == node("air") and (data[ivm] == node("default:dirt") or data[ivm] == node("default:dirt_with_grass") or data[ivm] == node("default:dirt_with_snow")) then
+					if (data[ivm + a.ystride] == node("air") or (swamp and data[ivm + a.ystride] == node("default:water_source"))) and (data[ivm] == node("default:dirt") or data[ivm] == node("default:dirt_with_grass") or data[ivm] == node("default:dirt_with_snow")) then
 						if biomes[biome].special_trees then
 							--print(dump(biomes[biome].special_trees))
 							local tree_type = biomes[biome].special_trees[math.random(#biomes[biome].special_trees)]