sinking tree's question

how much weight is needed to sink a 6ft xmas tree. its a scotch pine. i've got 4 of them.

One 8 inch concrete block per tree should do it.
I help sink some trees every year. We will have around 200 trees.
We tie four or five trees together and anchor them with three 12 inch concrete blocks.

would your recommend tieing them together or spreading each tree out a few feet apart form each other, like forming a square.

One block will sink it but where we fish theirs lots bass & cat fishers. what i do is use 2 blocks wire the tree where it stands up with the extra weight it,s harder to pull over. :) Also doesn,t get drug away from where you put it.

I tie a 2.5 gal jug in the top of mine... and I use 2 - 55# concrete test beams.... sinks great....