Line of sight sensitivity

How sensitive is the HD dish compared to the Standard 18 inch dish when it comes to line of sight obstructions? I currently have my standard dish pointing through a bunch of trees that are very close to the dish and I get great reception. Does the HD dish get better reception or will this be a major problem with the HD dish?  Moving the dish is not an option as the landlord states I can only upgrade if all things stay in current locations.