I am working on a planet were life (trees, plants, food, animals, humans) would be bigger/taller than Earth. I have learned that oxygen level or gravity, for example, could help change the size of life forms.
So here are the characteristics of the planet :
Nitrogen : 72,4%, Oxygen : 26%, Argon : 1,05%, CO₂ : 0,5%
I have settled the air density at 1.9 kg/m3, so approximately 148 892 Pa and 1,4 ATM (but I have doubts on whether it's good or bad for creating taller life forms). And I still don't know how much I would have to lower gravity (0,9g or maybe 0,8g ?)
There is a big continent near the equator, so there is a lot of huge forests (one of the reasons the level of oxygen is at 26%). A big part of the forests are near mountain range and/or coasts, so there are a lot of rivers, and so very fertile soil. These forests have very rich and abundant biodiversity (with different species of plants and animals than Earth, that I still have to create). And the trees would have similar behaviors than Redwoods (https://www.latimes.com/archives/la-xpm-2002-sep-01-adme-redwoods1-story.html), having water sources from both the ground and the canopy.
So considering all those characteristics, how tall trees, animals and "humans" could grow ? (bigger it is, the better)
Thanks for all the answers you will be able to give me !