diff --git a/engine/src/modules/climate/climate_spec_eval.gd b/engine/src/modules/climate/climate_spec_eval.gd
index 8cd64004..4fa15f04 100644
--- a/engine/src/modules/climate/climate_spec_eval.gd
+++ b/engine/src/modules/climate/climate_spec_eval.gd
@@ -14,6 +14,7 @@ static func ideal_terrain(tile: Variant, spec: Dictionary) -> String:
 	var tid: String = tile.biome_id
 	var temp: float = tile.temperature
 	var moist: float = tile.moisture
+	var canopy: float = tile.get("canopy_cover", 0.0)
 
 	var transitions: Dictionary = spec.get("terrain_transitions", {})
 	var rules: Array = transitions.get(tid, [])
@@ -23,7 +24,7 @@ static func ideal_terrain(tile: Variant, spec: Dictionary) -> String:
 	for rule: Variant in rules:
 		if not rule is Dictionary:
 			continue
-		if eval_condition(rule.get("condition", ""), temp, moist, tile.elevation):
+		if eval_condition(rule.get("condition", ""), temp, moist, tile.elevation, canopy):
 			var becomes: String = rule.get("becomes", "")
 			if becomes == "classify":
 				return BiomeClassifierScript.classify(tile)
@@ -32,22 +33,22 @@ static func ideal_terrain(tile: Variant, spec: Dictionary) -> String:
 	return tid
 
 
-static func eval_condition(cond: String, temp: float, moist: float, elev: float) -> bool:
+static func eval_condition(cond: String, temp: float, moist: float, elev: float, canopy: float = 0.0) -> bool:
 	## Evaluate a condition string from climate_spec.json.
 	## Supports: "field op value", "cond1 AND cond2", "cond1 OR cond2".
-	## Fields: temperature, moisture, elevation.
+	## Fields: temperature, moisture, elevation, canopy.
 	## Operators: <, <=, >, >=.
 	if " OR " in cond:
 		var parts: PackedStringArray = cond.split(" OR ")
 		for part: String in parts:
-			if eval_condition(part.strip_edges(), temp, moist, elev):
+			if eval_condition(part.strip_edges(), temp, moist, elev, canopy):
 				return true
 		return false
 
 	if " AND " in cond:
 		var parts: PackedStringArray = cond.split(" AND ")
 		for part: String in parts:
-			if not eval_condition(part.strip_edges(), temp, moist, elev):
+			if not eval_condition(part.strip_edges(), temp, moist, elev, canopy):
 				return false
 		return true
 
@@ -61,7 +62,7 @@ static func eval_condition(cond: String, temp: float, moist: float, elev: float)
 	var op: String = tokens[1]
 	var value: float = float(tokens[2])
 
-	var actual: float = _field_value(field, temp, moist, elev)
+	var actual: float = _field_value(field, temp, moist, elev, canopy)
 	if actual == -INF:
 		return false
 
@@ -83,7 +84,7 @@ static func ley_channeling_mult(tile: Variant, spec: Dictionary) -> float:
 	return ley_spec.get("on_ley_generic", 2.0)
 
 
-static func _field_value(field: String, temp: float, moist: float, elev: float) -> float:
+static func _field_value(field: String, temp: float, moist: float, elev: float, canopy: float = 0.0) -> float:
 	match field:
 		"temperature":
 			return temp
@@ -91,6 +92,8 @@ static func _field_value(field: String, temp: float, moist: float, elev: float)
 			return moist
 		"elevation":
 			return elev
+		"canopy":
+			return canopy
 	push_warning("ClimateSpecEval: unknown field '%s'" % field)
 	return -INF
 
diff --git a/games/age-of-dwarves/data/climate_spec.json b/games/age-of-dwarves/data/climate_spec.json
index f7d28a47..960f28da 100644
--- a/games/age-of-dwarves/data/climate_spec.json
+++ b/games/age-of-dwarves/data/climate_spec.json
@@ -406,7 +406,7 @@
         "becomes": "savanna"
       },
       {
-        "condition": "temperature <= 0.25",
+        "condition": "temperature <= 0.25 AND canopy > 0",
         "becomes": "tundra"
       }
     ],
@@ -443,6 +443,10 @@
       }
     ],
     "tundra": [
+      {
+        "condition": "canopy <= 0",
+        "becomes": "polar_desert"
+      },
       {
         "condition": "canopy > 0.30 AND temperature > 0.10",
         "becomes": "boreal_forest"
@@ -458,7 +462,7 @@
     ],
     "polar_desert": [
       {
-        "condition": "temperature > 0.10",
+        "condition": "temperature > 0.10 AND canopy > 0",
         "becomes": "tundra"
       }
     ],
diff --git a/tools/sprite-generation/spritegen.db-shm b/tools/sprite-generation/spritegen.db-shm
index 0ae3ed32..6f5f0624 100644
Binary files a/tools/sprite-generation/spritegen.db-shm and b/tools/sprite-generation/spritegen.db-shm differ
diff --git a/tools/sprite-generation/spritegen.db-wal b/tools/sprite-generation/spritegen.db-wal
index a5f9078b..2effd6e0 100644
Binary files a/tools/sprite-generation/spritegen.db-wal and b/tools/sprite-generation/spritegen.db-wal differ