The Anatomy of A Tree — And Why It Matters for Log Homeowners

People in the log home construction industry often throw around terms like hardwood and softwood, but there isn't much information out there that really breaks down the differences and educates people about the parts of a tree we use for the log homes we find so beautiful and timeless. In case you've been wondering about what really makes up a log home, and what parts of a tree are used in the construction of your log home, here's exactly what you need to know. We'll start with the most common question: What's the difference between hardwood and softwood?


The term "hardwood" refers to wood and logs that come from trees that shed their leaves in the winter. Maple, oak, poplar, and other trees with broad leaves that usually drop off in the winter are considered hardwood trees. On average, hardwood trees have a higher density and hardness than softwoods do.


Softwood trees are perhaps better known as evergreens. Most softwood that you see in home construction comes from trees with needles that remain on the tree even through winter. Spruce, pine, fir, and hemlock are all great examples of softwood trees commonly used in log homes. Generally, softwood trees are softer and have a lower density than hardwood trees, but it's important to remember that hardness of all wood types is measured on a spectrum, and it's possible to have a very hard softwood tree that's denser than a very soft hardwood tree. Measuring and understanding hardness across different tree species can be a bit confusing, but now at least you know the basic differences between hardwood and softwood.

Anatomy of the Tree

In the construction of a log home, only certain parts of a tree are used. To understand which parts of the tree are used in construction, and why, it's important to understand what the parts are in the first place. Every tree is made up of at least four discernable layers. (Most trees have more than this, but these four general layers are the most relevant to the log home building process). Those four layers are called bark, cambium, sapwood, and heartwood. Each layer serves a different purpose for the tree and has varying degrees of usefulness for log home construction. Let's dive into each layer:


This isn't exactly rocket science, but the bark is the outer layer of the tree. It's usually very hard and durable, and it functions to protect the tree from all sorts of potential hazards, like insects, fire, and abrasions, and it helps the tree keep moisture inside the trunk. Think of bark sort of like human skin, keeping the complicated inner systems separated from the outside. When it comes to construction, bark is always removed from logs before they're used to build a home.


Cambium is a thin layer just below the bark that facilitates the majority of a tree's growth. Cambium must also be removed from a tree before the wood can be used for construction, because it retains a lot of moisture, and provides an attractive home for insects and other pests. Without the cambium and bark layers, wood will dry much more quickly and will be less susceptible to insect infestations.


After the cambium, you'll find the living sapwood within a tree. If you cut out a cross section of a tree, sapwood would make up the majority of a tree's rings. It's typically a lighter color than the thin layer of cambium and is easily distinguished from the rough texture of the bark. All wood within a tree is first formed as sapwood, and this is the part of the tree that conducts water from the tree's roots out to the leaves, and that stores the nutrients the leaves generate from photosynthesis. Sapwood is moist and contains many nutrients that make it highly susceptible to decay and insect attack. This is why any home construction materials made from the sapwood of a tree must be dried thoroughly and treated with chemicals before they're suitable to build your home.


Finally, at the very center of the oldest trees, you'll find the wood that is no longer living — called heartwood. Heartwood contains a high concentration of naturally occurring pesticides, making it resistant to insects and decay. Heartwood is only found in older trees; the older the tree, the more heartwood it will contain. Centuries ago, most people only built their log homes from heartwood. They would select the oldest, widest trees, hew off all of the sapwood, and construct homes with "hand-hewn" logs. Because the heartwood is naturally resistant to pests and decay, many of those homes built, even those constructed in the 18th and 19th centuries, still exist. Today, because of the overharvesting of trees in earlier industrial decades, it is virtually impossible to obtain logs with a significant amount of heartwood. The modern log home is primarily constructed of sapwood that is felled, dried, treated and cured. Then, we treat log homes with borate products and stains that make them impervious to infestations and inclement weather, ensuring our modern log homes can last for years to come. So there you have it! The anatomy of a tree — bark, cambium, sapwood, and heartwood, and what we do with each layer of the tree to make it into the rustic log homes America has long been in love with. Whether you prefer hardwood or softwood, you can't beat a log home for charm and character. If you're building a new log home, or you're looking to take care of an older log home you love, Timeless Wood Care Products has everything you need to keep your log home looking beautiful for years to come. Check out the products we have to offer and don't hesitate to give us a call at (800) 564-2987 with any questions about maintaining your log home or cabin.