Mary Jo DiLonardo has worked in print, online, and broadcast journalism for 25 years and covers nature, health, science, and animals. Young trees sometimes have smooth bark that's unbroken by ridges.

The center of a tree or shrub stem (from roots to trunk, branches, and twigs) is woody, composed of xylem cells that conduct water from the roots to the upper parts of the tree. That woody section is ...

Why do trees have bark? Julien, age 6, Melbourne. This is a great question, Julien. We are so familiar with bark on trees, that most of us just take it for granted. But bark is one of the most complex ...

Trees are nearly always selected for their flowers, foliage, or form. Yet, at this time of year, there is an often overlooked arboreal feature that may achieve sudden prominence in the garden. In ...