That vs Which

This is really nit-picky stuff, but the answer is "That".

A clause with "which" is not essential to the sentence. Since the tree is essential to picture, you need that.

Another example.
The picture which contains a tree is on the wall.
The picture that contains a tree is on the wall.

The first sentence implies that the tree part is just informational. There is a picture on the wall and by the way it has a tree. The second implies that the tree is important. The picture I'm talking about is the one with the tree, not the one with an elephant.

The picture you mention--which incidentally does contain (show?) a tree--as you can see is on the wall just to your right

The only one showing a tree is posted with the others we've discussed directly in front of you to the upper left

Settling the issue, you'll find a snapshot containing a tree not at your feet but posted on the wall to your left, about in the middle and identified by the label, "See the dog urinate"

The answer in your specific example indicates proper grammar usage would be 'that':

Pls refer to the following:
http://www.writersdigest.com/online-editor/which-vs-that

In US English, only 'Draw a picture that contains a tree' is correct. That, whose, who, or whom can introduces a restrictive relative clause, and which, whose, who, or whom can introduce a non-restrictive relative clause.

In the sections of the world where British English is used, both words are equally correct to introduce a restrictive relative clause. Draw a picture that contains a tree; draw a picture which contains a tree, both are equally correct. Restrictive relative clauses can be introduced by that, which, whose, who, or whom, and a non-restrictive relative clause can be introduced by which, whose, who, or whom, but never that.

I al;ways said that we should use "That" cuz it sounds better.
Now I can sound like I know what the hell Im talking about.
Thankee.

Won't folks accuse you of being Professor Limey-Milquetoast?

US English only.

Ill kick their punk asses if they do. I havent kicked me a punk ass in many a year so I am quite looking forward to it actually.

Of course Adam "picture which" is alliterative

Wrong. please read the links provided. That is the choice as the suggested grammar.

Rag sorry but you misunderstand. The alliterative, having nothing to do with grammar, is to be avoided in some situations, eg, conversational text

In what way is that alliterative?

Good grace, grab a grammar! Then gradually get a grain of grandiloquence or something gratifying..

I see absolutely no alliteration in OP query.

Sorry Rag that's as close as I could come without undertaking a major search in Reverse Dictionary, which incidentally I don't often find very useful

http://onelook.com/?w=alliteration&ls=a&loc=home_ac_alliteration

But I must say you fellas really do get highly technical

http://able2know.org/topic/308067-1

Sorry, Dale..once again you've totally lost me.

Again sorry, Rag, but you had objected to "alliteration" as describing anything in the OP, whereupon I explained that perhaps that was the wrong word for a repeated sound in nearby words

oh.I guess the word assonance is what describes what you were looking for.

Yes, yes, thank you Rag

http://onelook.com/?w=assonance&ls=a