If a person was to add some Christmas trees to the lake, what would be the best depth to do it in?

first I would ask if the lake is at full pool.. then find locals that fish the lake and ask them, because most lakes are different. .on the mostly deep central tx lakes we fish, 14 to 22 feet seems to be good most of the year, but in winter were finding them 25 to 36 feet.. . on shallower, more stained lakes you can put the brush shallower.

10' to 20' will be the best general depth range for more of the year. Some lakes fish shallower than others, and some areas of a lake hold more fish than others. Knowing that kind of info and the contours can help you decide whether to lean more towards the 10 or the 20 or in between or whatever. It's a trial and error thing regardless. Some work, some don't.

What time of year are you looking to fish them?

Good question. For the best returns on your effort you should first know the characteristics of the lake because there are a few variables to consider. ie. The overall depth of the lake,is it an Ox Bow,is it creek or river fed ,does it have channel swings that run near points etc etc. Otherwise you are just adding structure willy nilly & just hoping for the best instead of placing it strategically. JMHO

When I first started putting brush in always the places that made the best places were areas that I caught a crappie while going down a bank bass fishing or whatnot. There is a reason those fish were there. If there is no brush close put one where you have done the same. Crappie like to suspend. A rough estimate without knowing your lake habits would be that you want your brush to top out at your target depth which should be half of the water column. Example.: 25 feet deep make your pile top out about 12.
What Leaningpost and thump is saying is every lake the fish like to stay a majority of the year around a certain depth, Up here at Broken Bow where it is super deep the fish like 12-15 feet alot. They may be over 50 feet of water but only 12 feet, Figure out the depth they like and build accordingly.

Good advice above,

I fish Lake Palestine, it does not fluctuate much in depth. With the lake at full Pool level , 17 to 20 ft are our best depths.
These hold fish most of the year. If I wanted a spring time spot , I would go shallower 12 to 16, For a late fall early winter, I would
go deeper 20-24.

good luck

MO