All the known giant trees occur in mesic climates, and nearly all of them are found in three regions: western North America (from California to British Columbia), Southeast Asia (especially Borneo) and southeastern Australia (especially Tasmania).
By analyzing the interplay between these forces in coast redwoods (Sequoia sempervirens), a team of biologists led by George Koch of Northern Arizona University calculated the theoretical maximum tree height or the point at which opposing forces balance out and a tree stops growing.
On the other hand, gravity makes it more and more difficult to haul water upwards from the roots to the canopy as the tree grows, and leaves thus become smaller near the top.
They discovered that despite the moistness of the ground far below, the leaves at the treetops struggle to get enough water, so they are effectively living in a constant drought.
[46] Other researchers have developed models of maximum height for Coast Douglas-fir (Pseudotsuga menziesii var.