wood

Rick, welcome to the boards.
If you are doing good at fishing the wood devote some time to your self to try fishing the rip-rap, weeds, and other structure especially if your not getting bit on the wood. As far as the best time depends on so many variables such as the wind, current, air & water temp., depth, and sunshine versus cloud cover. For instance if it is a sunny summer day the wood may provide shade and ambush locations beneath it near the outer edges, but if it is a cooler sunny day in spring or fall the wood absorbs the sun and the bass may relate to the sides or top of the wood tighter to the bank for the warming water. Then again if it is cloudy and the temps are fairly mild they may be scattered out away from the wood on the first drop or suspended and cruising nearby. When your flipping bite goes away try a crank bait or spinnerbait outside the wood and if that doesn't produce then go to the other cover as I mentioned before and give it a shot.
I'm sure that Tom and Jim will provide a ton of in-depth info. on this subject, these guys are just awesome for the amount of knowledge and different perspectives on these subjects.
Best of luck.

Wood; location, location, location, thats about it. Oh yea, there is also wood types like salt cedars, hard woods, cypress, willows, brush, trees, docks, etc.
Wood often is the primary cover in any lake or river classification. Wood that is  growing or dead standing in shallow or deep water and floatsum. Wood attracts plankton and other micro organisms, that in turn attract all kinds of prey for bass, plus provides ambush sites and a sanctuary.
Right now in the cold water period or pre spawn, depending where you are, bass hold in or around wood that is located on or near deep water break lines. Since trees tend to grow along creek and river channels or in the bottom of canyons where rain water run off provided soil to root and water to grow, wood can be the highway for bass to migrate to spawning flats. Big female bass stag around wood to rub against to loosen egg sacks and ambush prey fish or crawdads. Locate and isolated tree or brush on a deep break and that cover will hold big bass all year, except during the spawn. During spawn the bass use wood to protect the nest site in shallow water.
Tom

Tom explained that bass and baitfish are attracted to wood. Algae grows on it and plankton feed on that, and baitfish feed on both, and bass, , crappie and other species feed on the baitfish. That why fish are attracted to any stable surface like riprap where current is low and sun hits to allow photosynthesis.

That goes on all year long, so the ingredients for catching fish around wood are always there. In spring it's obvious why they might not be there much, active closer to spawning areas. In fall they are following baitfish that avoid traps like woods, moving to open water.

Lots of lakes have long ago given up the last standing wood, but if you have standing submerged trees it's a good idea to learn the seasonal situations. I'll talk a bit about winter. Whenever part of the trees stick up above the surface, birds often roost there all winter. Their droppings fertilize the water around the roost tree, so algae gets thicker around those trees than those completely under water. Look for roost snags.

It should be obvious the snags provide excellent shade in summer, but in winter they also provide dark ambush vantages for bass, the shade being deeper. As noted above any sunlight penetrating to the wood warms it and is retained a while, another attractor for a cold blooded bass.

Now lets bring in another fact do we can tie some things together. We know bass are lethargic, not willing to chase a meal down. They hide behind snags waiting for a hapless baitfish or panfish to get too close. Bream and crappie are there too, enjoying the bounty of a stand of snags. Whenever a prey fish is attacked it emits sounds and pheromones to alert their neighbors. Little fish dart suddenly in every direction, slamming into wood worrying too much about what might be behind them. They don't have the same lateral line feature bass have, so are more prone to bang into things.

Whenever fishing wood, ALWAYS bang your lure into wood, regardless of lure type. Bass see that as perfectly normal, and see it as an advantage. So bang and pause a second like a baitfish recovering from getting its snout smashed. Guide the bait, whether a spinnerbait, jig, crankbait, whatever, to hit as much wood as possible.

Winter is a time when most activity occurs around snags. A hot summer period is another peak period when all fish want to be shallow but need some shade. A less dramatic time is as Tom pointed out when females prepare for the spawn. The girls are both massaging egg sacks and leaving a scent trail for a male to locate them.

Right now through winter locate the tallest trees associated with steep drop offs. I head straight for 90' tall submerged wood on a slope that goes from 10' deep to 100' deep in about 100-150' of surface distance. For ya'll fishing on shallow lakes just look for wood on steep slopes even if that only involves 3' of elevation difference, or find a beaver hut, brush pile, or laydown.

Jim

Excellent point to ponder, Tom. To me the first rule in finding a bass bite pattern is to nail down the active depth as the day progresses or as weather changes significantly. Most biting bass will all be near a specific depth range, but then the next step is to identify what they are relating to at that depth.

In the case of the woods, I try to locate a small isolated patch of trees away from the "forest" with no sign of existence above water, and preferably where a small creek came out to join a larger one, forming a hump or ridge. Few anglers will have fished that invisible spot, well beyond the line of visible stickups. If the active depth is right out there, and baitfish or other forage is present, you are prospecting a potential honey hole. I look at woods the same way I do fields of hydrilla or lily pads, ignoring the main patch, locating the little isolated clumps over water with the right depth range.

I catch bass early in the shallow inside edges of woods, too, but believe that's because during the waning dark hours a few bass are still chasing minnows shallow. As the sun comes up and their security drains, they head back deeper, but not far any season unless migrating to a spawn area and just stopping off for a quick meal. Keep in mind bass are very conservative about burning calories, and they don't swim a half mile away every day. In winter they are ultra conservative.

Another "secret" bassin place is humps out in the open lake with trees standing around the edges. Baitfish and bass alike love those places, so will hold in them at the main feeding depth of the hour. The trees might be rooted 50' down, but the fish might be active half way up. If doing that they are holding true to the lake-wide feeding depth, but the main clue is they are relating to wood somewhere in that zone. If they are not there then search weedlines, channels, ridges, bluffs, docks, whatever variety your lake offers. It would be pointless to try laydowns in 12' of water when the active zone is at 18'. 

Jim

Whatever you are looking at; wood, weed beds, expanse of open water, miles of shore line, you need to try to keep everything in perspective and ask yourself the basic questions, where are the bass going to be located today, will they be holding on edges or isolated structure? The answers ares there on the water. What is the water temperature? What seasonal period is this? What depth is the life zone? What are the bass feeding on? You should know what the seasonal period is. You can determine what the surface water temperature is with a simple thermometer. You need good sonar to determine the life zone or you will be using a lot of time trying different lures at varying depths to figure that out. The bass will be feeding on available prey and the seasonal period helps to answer that question, your electronics can help locate schooled bait fish and bass. Location will be answered by knowing the basic bass habits, their preferred bait during the seasonal period helps to eliminate locations the bass should not be using. There is old saying "fish where the are not where they there not". The winter, pre-spawn,spawn, post spawn and fall are easier periods to determine bass location. Summer period is the most difficult because the bass have so many choices, prey is every where. Summer nights however are more predictable, the bass move up to shore line ambush sites and roam the banks looking for prey. Winter the cold water period, see post. Pre-spawn, see post.
Spawn, the bass are on the banks in water where the depth of light reaches the bottom, you should be able to see the bass. Bass may use wood to reduce entry to the nest site, like a protective wall on one side. Post spawn the bass move back out to secondary points and hold in wood cover to rest and find an easy meal without chasing it down, as they are both hungry and weakened from spawning. Fall the bass leave their summer locations and follow bait fish migrations. The late fall period the bass tend to go deeper to secondary breaks as the water cools. I plan to write more on seasonal periods as time allows. Have a great new year bass fishing and hope we have some fun along the way.
Tom