Science, Tech, Math › Animals & Nature 11 Things You Should Know About Trees Share Flipboard Email Print Animals & Nature Forestry Tree Structure & Physiology Tree Identification Basics Arboriculture The Science Of Growing Trees Conifer Species Individual Hardwood Species Pests, Diseases, and Wildfires Tree Planting and Reforestation Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Dinosaurs Evolution View More By Steve Nix Forestry Expert B.S., Forest Resource Management, University of Georgia Steve Nix is a natural resources consultant and a former forest resources analyst for the state of Alabama. He is a member of the Society of American Foresters. our editorial process Steve Nix Updated February 24, 2019 Trees are literally everywhere. A tree is the most obvious and remarkable plant you will see when you venture outside. People are infinitely curious about trees in a forest or a tree in their yard. This tree guide will enable you to satisfy that curiosity and explain a tree in detail. 01 of 11 How a Tree Grows Alanzon/Wikimedia Commons/CC BY-SA 3.0 Very little of a tree's volume is actually "living" tissue. Just one percent of a tree is actually alive but you can be assured it is working overtime! The living portion of a growing tree is a thin film of cells just under the bark (called the cambium) plus the leaves and roots. The cambial meristem can be only one to several cells thick and is responsible for Nature's greatest work — the tree. 02 of 11 Parts of a Tree DEA PICTURE LIBRARY / Getty Images Trees come in various shapes and sizes but all have the same basic structure. They have a central column called the trunk. The bark-covered trunk supports a framework of branches and twigs called the crown. Branches, in turn, bear an outside covering of leaves — and don't forget the roots. 03 of 11 Tree Tissue USFS Tree tissues are a combination of bark tissue, root tissue, and vascular tissue. All these tissues made of numerous cell types are unique to the plant kingdom and to trees specifically. To completely understand a tree's anatomy, you must study the tissues that support, protect, feed, and water a tree. 04 of 11 The Structure of Wood marcoisler / Getty Images Wood is a combination of living, dying and dead cells that function much like a lamp wick, moving liquids up a tree from water-seeking roots. The roots are bathed in a nutrient-rich liquid which transports basic nutrients to the canopy where all is consumed or transpired. Tree cells not only transport water and nutrients to leaves for photosynthesis but also form the entire structure of support for the tree, store usable sugars, and include special reproductive cells that regenerate the living inner and outer bark. 05 of 11 Where Trees Live kokouu / Getty Images There are very few places in North America where a tree just can't grow. All but the most adverse sites will not support native and/or introduced trees. The United States Forest Service has defined 20 major forest regions in the United States where certain trees are most often seen by species. Here are those regions. 06 of 11 Conifers and Hardwoods Jon Houseman/Wikimedia Commons/CC BY-SA 4.0 There are two major groups of trees in North America — the conifer tree and the hardwood or broad-leaved tree. Conifers are identified by needle-like or scaley-like leaves. The broadleaf hardwood tree is identified with wide-bladed, broad leaves. 07 of 11 Identify Your Tree With a Leaf Corbis via Getty Images / Getty Images Find a tree in the forest, collect a leaf or needle and answer a few questions. At the end of the question interview you should be able to identify a tree's name at least to the genus level. You will most likely be able to select the species with a little research. 08 of 11 Why a Tree Is Important stock_colors / Getty Images Trees are important, valuable and necessary to our very existence. Without trees, we humans would not exist on this beautiful planet. In fact, some claim can be made that our mother's and father's ancestors climbed trees — another debate for another site. 09 of 11 A Tree and Its Seeds Dan Kitwood / Getty Images Most trees use seeds to establish their next generation in the natural world. Seeds are tree embryos that burst into growth when conditions are exact and transfer tree genetic material from one generation to the next. This fascinating chain of events — the formation of seed to dispersal to germination — has fascinated scientists since there were scientists. 10 of 11 Autumn Tree Color Alpsdake/Wikimedia Commons/CC BY-SA 4.0 Autumn turns on a very miraculous switch that colors most trees in broad-leaf forests. Some conifers also like to display color in fall. The fall tree senses conditions that tell it to close shop for the winter and begins to prepare for cold and harsh weather. The results can be astonishing. 11 of 11 The Dormant Tree 1brettsnyder/Wikimedia Commons/CC BY-SA 3.0 A tree prepares for winter in early fall and protects itself from winter. Leaves fall and the leaf scar closes to protect precious water and nutrients that have been collected during spring and summer. The entire tree undergoes a process of "hybernation" that slows growth and transpiration which will protect it until spring.