With accent marks:
Кто в лес, кто по дрова́.
Some to the forest, some for firewood.
Usually this phrase is said with irony and criticism at the same time. It is used in situations when people, seemingly doing the same thing or trying to achieve the same goal, do it without any coordination in their actions so everybody ends up doing his own thing. Therefore, they cannot succeed.
The saying takes an example of a person just walking in the forest and a person gathering firewood: they are both in the forest but are doing different things.
Most often the phrase is used about a discordant singing choir, but can be applied to any action performed by a group of peope.
Other Russian proverbs
You can't command to the heart.
When I eat I am deaf and mute.
Each sandpiper praises its swamp.
A bad example is contagious.
Don't bring your set of rules in a foreign monastery
To live a life is not the same (not as easy) as to go through a field.
Water wears away a stone.
There is no smoke without fire.