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Florida Land Steward

Florida Land Steward

« Timber Management

Growth and Yield

Predicting the future growth and yield of your forest stand(s) is an essential part of the planning process for your forest land. This page will provide you with a basic understanding of the concepts of growth and yield. A look at these concepts in the context of even- and uneven-age stand structure will also be provided.

Trees accumulate woody material (branches, bole, roots) over many years, a layer per period or year.  Like people, trees do not grow according to a standard form, they grow short and thick, tall and slim, and everything in between. 

Growth is measured as change in some characteristic (weight, basal area, volume, etc.) over some specified amount of time.  For example, let's say your stand of slash pine might increase in volume by 2,000 cubic feet over 10 years.  If we state this as an annual increment, we would say that the stand's growth is equal to 200 cubic feet per year (2,000 cubic feet per year / 10 years). 

Yield actually has 2 meanings.  It is: 

  1. the amount of some characteristic that can be harvested per period, or
  2. the total amount that could be removed at any time

In our slash pine example, an average of 200 cubic feet could be harvested from the stand each year, or 2,000 cubic feet could be harvested after 10 years.  If this yield was equal to the growth and could be continued at that level, we would say that your stand was under sustained yield management.

Another commonly used measure of growth and yield is the cord or cords per acre.  A cord is 128 cubic feet of stacked roundwood (whole or split, with or without bark) containing wood and airspace, with all the pieces of similar length and lined up on approximately the same direction. Example: a pile of firewood 4' x 4' x 8'. 

Generally, the maximum amount of output that a forest or stand can yield at any time is the growth that has accumulated up to that time, and the maximum yield that can be removed in perpetuity per period equals the growth of that forest or stand per period. 

Growth and yield can be measured in physical units or in value, often the variable of interest.  Since physical measures form the basis of value measures, we will focus on the physical measures here.