Ok, got a couple minutes before I have to head out.
First of all, dealing with HOAs can be a PITA. Getting them on board with an idea can be a chore. So some of these things I'll suggest for you might not be taken seriously by them, especially if pond management is not considered something that is important or necessary in your area. It's not taken seriously yet in my area yet. Pond owners think it's simple, but there's so much that goes into pond management that you can only know by doing extensive research or have extensive experience. Anyway...
The fishing in this pond, do you generally catch very few bass, but they're large when you do? And rarely ever see big bluegill? If so, this is an out of balance pond, but that can be a good thing, depending on your goals. If you're the type of angler that doesn't care about numbers of fish or sunfish, just want those occasional toads, then this is exactly the kind of set up you like. Typically, a pond is going to be one way or the other. Numerous stunted bass will result in big sunfish. Big, but few, bass will result in a pond with very few big sunfish and also few and far between small bass. The first happens because there is not enough food for the large number of bass in the pond. This is the second most common pond related issue behind vegetation. Basically, too many mouths to feed due to catch and release tendencies. Ponds should have a selective harvest strategy in place to prevent this. Removal of <14" bass is a common practice. The latter issue is where the few big bass there are, are eating their fill and eating multiple size classes. This is also common in ponds with little to no cover, like yours. This gives the small fry nowhere to hide and they're easily preyed upon.
So the first question you'd be asked by a pond consultant would be, what is your goal? Do you want trophy bass, trophy bluegill or a relatively balanced pond? Typically, a 100% balanced pond is impossible, though you can get close.
Structure, or cover (and there is a difference), generally should be placed in 3-6 feet of water. This is the depth that bass and bluegill typically prefer. You can probably tell with simply walking out into the water where that depth is in your pond. If not, you can guess. The fish aren't going to care if you're a foot or two off.
Christmas trees are commonly used as cheap easy to access structure. However, there are some drawbacks. First of all, they decompose. This does two things. First, you have to replace them every 5-10 years. Not a big deal, especially in the short term. Another issue is when something decomposes in a body of water, it uses oxygen. This can cause a dissolved oxygen crash in a small pond, which can result in a fish kill. I don't think you'll have this problem since it would take a lot of Christmas trees in a pretty small pond to cause this. The last drawback is simple. Trees are lure collectors. You'll get snagged up while trying to use them as fish attractors. Here's
a great thread with tons of structure ideas. PVC is the best way to go if you can get the materials and build them. Or have the resources to buy them. First of all, they don't decompose. They'll be in your water forever. Algae grows on it, which creates incredible habitat. Lastly, lures bounce right off PVC. Ok, so that is structure. This is what holds fish, so anglers love it. Cover is much more extensive and what you'll want if you want a more balanced fishery. Unfortunately, this isn't going to be an easy sale to your HOA. Do you have any vegetation in the pond right now? This and rocks and timber are best to hide those fish that make up the base of your fish population.
A friend of mine started up a business not long ago called Fishiding
. It's very cool. He utilized used house siding to create fish habitat. These aren't cheap, however, so you may want to see if you can build some of your own. It's easy and you can typically get scrap pieces of PVC simply by putting an ad on Craigslist, going to a local fishing message board and asking, or any number of ways. Calling plumbing companies is another option. As I said earlier, I had the pleasure of helping place structure in Chris Kelsay's pond. Article [url=http://www.fishiding.com/nfl-player-chris-kelsay-tackles-fishing-lake-project-in-nebraska/[/url]. He has another pond that we'll add more structure to as well. There's only a couple feet in this pond, so you get an idea how deep we placed them. The article goes into the benefits of habitat as well. There's more and more research out there that confirms habitat is incredibly beneficial to the entire ecosystem of a body of water. It can directly effect fish sizes and populations.
One thing I would shy away from is throwing more fish at the problem. Without a detailed survey of the pond (that is an option for you as well, but again, HOA issues there), you won't know exactly what to add. You could just be furthering the issue. This is a common answer from someone who wants you to believe they know the answers. Not saying that isn't sometimes an option, but it rarely works. Even very aggressive forage stocking plans, in a pond with a present fish population, are rarely successful.
Ok, gotta plug the link in my signature. You're a perfect candidate for visiting this website, Pond Boss
, registering and asking questions. The guys there are fisheries biologists, pond managers, pond owners, fisheries professors, etc. and it is BY FAR the best place on the web to get pond related issues answered. You'll love it and you can seriously (no exaggeration here) thousands of dollars, simply by reading free content. I don't get paid by Pond Boss, so I have nothing to gain by you going there, other than peace of mind that you're getting the advice you want. I am a moderator there so if you do register, hit me up (Omaha's my handle).
Hope that helps bro!