The information within this post is directed to those that live in, or travel to broad-leafed forests and that are not in an area that greatly suffers from deforestation. Here I will discuss my thoughts on proper harvesting of timber for various purposes.
The common advice and practice among those that practice bushcraft, primitive living skills and the like, is to only harvest trees that are dead standing or somewhat recently downed from high winds or some other natural event. While this is generally good advice for the beginner, it neglects certain truths that must be eventually addressed if one seeks a deep relationship with the land.
One of the unfortunate truths of our world is much of the forests have been clear-cut in relatively recent history. The species that dominate most areas are now the quickly growing varieties, in my area that would be the Tulip Polar, Buckeye and the various species of Maple. The mast crop species are also the slowest to grow, such as Oak, Beech, Walnut, Hickory and the like. There is also the fruit bearing species such as Mulberry, Pawpaw and Persimmon.
In a healthy broad-leafed forest, these food producing trees form the base of the food-chain and are of upmost importance. Without these vital varieties, the forest is bereft of nutrition and the wildlife will not only diminish, but due to the scarcity of proper nutrition, the animals loose their robustness and more easily fall prey to disease and starvation. Poplar, Buckeye and Maple do very little to feed wildlife, and in proper proportions should make up only a small percentage of what grows here in southern West Virginia. A similar situation is present in most hardwood forests. We must do something about this.
Worse than the native quickly-growing species coming to dominate, are the invasive species that have been introduced to our forests. Where I grew up in southeast Texas we had, and still have, a major issue with the Chinaberry tree. It grows so profusely that it'll push out and smother all other native trees and entire forests will develop where more than 90% of the trees are Chinaberry. The native Oak, Elm, Pecan, Mulberry and many others have been decimated in certain areas there. Truthfully, we need to be proactive in restoring our forests to the natural proportions as found in old-growth forests.
It is commonly forgotten that mankind is a natural feature of the Earth. Many animals have developed a symbiotic relationship with specific plant species. My belief is that man evolved to be a steward of the land, to live in symbiosis with all life. We have forgotten that we can have a profoundly positive effect on the environment if we simply make our way through this world in a way that considers ALL life, and even our mineral brethren.
By incorporating permaculture principles and a keener understanding of forest ecology into our practices, we can be the front line, the boots on the ground that actually does the necessary work to restore our environment. The beautiful thing about this is that by simply being more conscious and knowledgeable in getting what we need from the environment, we can greatly improve the natural abundance that wouldn't be there otherwise.
I encourage you to learn what trees form the base of the food-chain in your area and avoid harvesting these. Instead of focusing on the use of solely dead wood, your primary source of construction timber should be first the invasive species. Next, look to the quickly-growing species that does little to feed the native wildlife. Also, trees for habitat must be considered as well. Here the Sycamore and Beech form hollows that provide shelter for a great many animals.
After that, focus on the food and habitat producing species that might be growing too closely together. Trees, like all life, are in constant competition with one another for nutrients. If they are too tightly spaced, none will be receiving adequate sun, water and nutrition from the soil and they will become weak. In this weakened state, the trees are now susceptible to fungal infection and disease, putting the surrounding ones at risk as well.
If it's on the ground, it's most likely rotten and full of mycelium. Even dead standing can be greatly degraded from the mycelium consuming the cellulose and isn't suitable for construction. Remember, decay is vital for the health of the forest. Many species of plants, animals and fungus absolutely depend on decaying timber. By always removing the dead wood, we are robbing the forest of vital sustenance.
A greater consciousness must be cultivated. Following the "no cutting live trees" rule is very short-sighted and encourages the neglect of pursuing a deeper relationship with the land. Look into the writing of Paul Stamets, his book "Mycelium Running" is an excellent work. Research permaculture, especially as it pertains to developing food forests. Geoff Lawton has an great channel YouTube on permaculture. Food forestry can easily be adjusted to focus on native species.
Pick up books on local forest ecology and gain an understanding of what forms the base of your local food chain. Many colleges, universities and state and federal parks offer forest walks where you can get a deeper understanding of your local environment. Pursue knowledge any way you can. By doing so we can take our natural place as stewards and make the wilderness more bountiful than it would be without our presence.
So to recap, focus your harvesting to these in order:
1) Invasive species
2) Quickly growing species in excessive numbers
3) Vital mast crop & habitat species growing in too close proximity
4) Windfalls and other recently downed trees
5) Dead standing