DELIOCOURT LAW AND THE TRUNCATED LAW

New estimates are proposed for de Liocourt's law parameter q (the q-ratio) and for the number of trees in each diameter class, which depends only on the average diameter of the tallied trees. A new empirical diameter distribution that fits real tree numbers and tree volumes in the diameter classes better than de Liocourt's law does for both even-aged and uneven-aged stands is then presented. It is named the truncated law, because the age of the trees is truncated on the right by a maximum value. It depends on two parameters, alpha and beta, alpha-being related to the average annual thinning rate and beta-being related to the maximum age of the trees and the average diameter of the oldest trees. It is shown that the average diameter of the tallied trees, as well as the q-ratio, depends on the thinning rate, on the maximum age of the trees, on the average diameter growth for a specific set of environmental conditions, and on silviculture. de Liocourt's law is a special case of the truncated law.