Annual Forest Growth
A forest owner should understand how to maximize their annual growth. This is how someone who manages any other agricultural crop makes the most money.
Traditional forest managers brings in a logging crew every 15-25 years to do a heavy harvest. That is how the loggers and foresters make the most money - but not the forest owner! We have found a much better way!
Sunshine, water, nutrients, and warmth are the key requirements for forest growth. How much of these inputs you have available in your location will determine your maximum annual growth. Whether your trees can attain this potential growth is up to you.
Individual tree tops form the forest canopy. The canopy of the forest is a living solar collector. If your solar collector is intact, continuous, and healthy - you can grow a lot of timber. (If a heavy harvest destroys the forest canopy, it will take many years to rebuild it before you will attain a good annual growth again.) Our harvest of one tree per acre each year removes about 4% of the canopy. Including natural disturbance, we try and keep our canopy surface at 80-90% complete. Excellent!
In hilly topography, the canopy is affected by the land's slope too.
Each individual tree is a living solar collector. The leaves catch the sunlight and funnel the energy down to rest of the tree for respiration and growth. For trees to grow in diameter, a large healthy funnel is needed.
Here is a high quality red oak tree with a well proportioned funnel shaped crown. This tree is 60 years old. This forest was just thinned so this tree has room to expand it's crown and continue to grow with FULL VIGOR.
The best way to know when and how much to thin a forest is to monitor the diameter growth of the good trees. In our climate in the U.S., good trees should grow with an annual diameter increase of 1/4" to 1/2". In general, a hardwood tree should have a crown width equal to one third of the tree's total height and a conifer should have a crown width to tree height ratio of 1:4. This form will produce good diameter growth.
Here, a forest growing with Full Vigor can grow about 500 board feet each year. In the southern U.S. and Pacific Northwest an average forest can produce 1,000 board feet per year. In the tropics the potential is even higher. The average growth on my neighbors lands here is about 25% of the potential due to industrial harvesting for 100 years. SAD!
Forget Basal Area, Trees per acre, Volume per acre.... that is for Industrial Forestry. As a forest grower, there is no formula or chart to tell you how much you should harvest - you need to learn to observe your forest and harvest just a portion of the natural output - always improving the quality and annual growth.
Your good trees are affected mostly by the other trees that surround them. We manage our trees in small groups to control spacing & tree form & diameter growth - to maximize our annual growth. The rest of the acre will be gradually managed too!
An annual harvest supports an operating business. A steady income is important. An annual harvest keeps you involved and informed. A small annual harvest keeps the forest beautiful and productive. A small annual harvest encourages natural regeneration and succession to proceed. Large harvests expose the soil to erosion, allow lots of light in to encourage weeds, and change the forest dramatically.