I seem to recall for some long-ago course that the 8,000m peaks are up around the compresssive limit so yoou couldn't really have a taller mountain.

Which would also serve as reasonable challenges for genetic and molecularbiological engineering so ... what's your point?

Or do you mean to suggest that the failure of any accepted tree height records to surpass the maximum capillary distance can be explained by some other factor? (Based on your other comment it seems safe to assume that isn't what you meant but anyhow.) That seems far too convenient given that the observed cutoff is within the expected range.