Gene, the narrator, has returned to Devon School fifteen years after he graduated. The revisiting of tree that played such a pivotal role in his experiences was a primary goal of his visit.
Before even identifying the specific tree he was searching for, Gene was surprised to discover that there was more than one tree along the bank of the river. He had never noticed that there "was a scattered grove of trees."
Eventually, Gene locates the particular tree he had come to find. As a schoolboy, the tree had been physically taller in relation to Gene's size than it was when he returned to it as an adult; this change in perspective was a surprise to Gene.
it seemed...to resemble those men, the giants of your childhood, whom you encounter years later and find that they are not merely smaller in relation to your growth, but that they are absolutely smaller, shrunken by age...the old giants have become pigmies while you were looking the other way.