"Ari is determined to build the tallest block tower in the world, even though his towering creations keep toppling over. But falling blocks can't dampen his spirits today -- field trip day! And the class is off to see another towering sight: giant sequoia trees. Ms. Mole leads Ari, Elinor, Olive and the rest of the class deep into the sequoia forest to find the tallest trees. When the finally reach the giant sequoias, they are astounded! How can these tree grow so tall and stand so straight? With a new mystery of nature to solve, the three friends set to work looking for clues. The answers to their questions might just help Ari build a better block tower, too! Sidebars with more science facts and a key vocabulary words are interspersed throughout, and an activity at the end of the book teaches kids a fun and simple method for measuring the height of a tree."--Provided by publisher.