stretch tree of depth 16	 check: -1
65536	 trees of depth 4	 check: -65536
16384	 trees of depth 6	 check: -16384
4096	 trees of depth 8	 check: -4096
1024	 trees of depth 10	 check: -1024
256	 trees of depth 12	 check: -256
64	 trees of depth 14	 check: -64
long lived tree of depth 15	 check: -1
