After spending several hours looking for a decent sized (13 block diameter) Natura Redwood I found a great plains biome bordering several useful others and decided to "roll my own" and cheated in two stacks of saplings.
I like to start with a 9x9 array as I almost always got 13x13 trees that way where a 7x7 array usually gave me a 9x9 or 11x11.
I started the first day planting my saplings in the middle of a chunk. I hadn't even finished planting when a 9x9 tree grew, giving me two hearts of damage in the process. (This is the tree in the background of the exterior shot). I spent that game-night in the Village (foreground of exterior shot).
The following day I tried again, making sure I hadn't accidentally made a 7x7 array by planting 5 rows of 9 on one side and then went to the opposite side of the array. I hadn't planted 2 rows before another 9x9 appeared where I was planting, dealing me another 2 hearts damage.
I went to gather the majority of the saplings I planted, just a few blocks away, when a 13x13 tree suddenly grew in my face, dealing yet another 2 hearts damage!
Here are the photos to prove it:
And the extra Interior space:
I like to start with a 9x9 array as I almost always got 13x13 trees that way where a 7x7 array usually gave me a 9x9 or 11x11.
I started the first day planting my saplings in the middle of a chunk. I hadn't even finished planting when a 9x9 tree grew, giving me two hearts of damage in the process. (This is the tree in the background of the exterior shot). I spent that game-night in the Village (foreground of exterior shot).
The following day I tried again, making sure I hadn't accidentally made a 7x7 array by planting 5 rows of 9 on one side and then went to the opposite side of the array. I hadn't planted 2 rows before another 9x9 appeared where I was planting, dealing me another 2 hearts damage.
I went to gather the majority of the saplings I planted, just a few blocks away, when a 13x13 tree suddenly grew in my face, dealing yet another 2 hearts damage!
Here are the photos to prove it:

And the extra Interior space:
