Transpirational pull

Transpirational pull results ultimately from the evaporation of water from the surfaces of cells in the interior of the leaves. This evaporation causes the surface of the water to pull back into the pores of the cell wall. Inside the pores, the water forms a concave meniscus. The high surface tension of water pulls the concavity outwards, generating enough force to lift water as high as a hundred meters from ground level to a tree's highest branches.

Reference

• The comprehensive textbook Biology, 6th ed., by Neil A. Campbell and Jane B. Reece, published by Benjamin Cummings, has been used as a source.