Fixed issue with unmanaged forest fraction when updating protected areas.

src/ac/ed/lurg/landuse/LandUseItem.java

@@ -323,6 +323,9 @@ public class LandUseItem implements InterpolatingRasterItem<LandUseItem>, Serial
 				LandCoverType toLc = ModelConfig.ENABLE_LAND_SHARING || lcType.equals(LandCoverType.BARREN) ? lcType : LandCoverType.NATURAL;
 				LandKey toKey = new LandKey(toLc, LandProtectionType.PROTECTED);
 				double a = Math.min(getLandCoverArea(fromKey), diffArea);
+				if (a < 1e-9) {
+					continue;
+				}
 				moveAreas(fromKey, toKey, a);
 				diffArea -= a;
 			}
@@ -335,6 +338,9 @@ public class LandUseItem implements InterpolatingRasterItem<LandUseItem>, Serial
 				LandKey fromKey = new LandKey(lcType, LandProtectionType.PROTECTED);
 				LandKey toKey = new LandKey(lcType, LandProtectionType.UNPROTECTED);
 				double a = Math.min(getLandCoverArea(fromKey), diffArea);
+				if (a < 1e-9) {
+					continue;
+				}
 				moveAreas(fromKey, toKey, a);
 				diffArea -= a;
 			}