87. In a forest management sector, a holder of a management permit shall harvest the trees or parts of trees of the species or groups of species listed in his permit and containing a volume of usable ligneous matter, including previously felled trees, lodged or overturned trees and trees affected by fire, insects or disease.
Where cutting is finished in the forest management sector, the permit holder shall inspect the sector and determine the volume of trees or parts of trees referred to in the first paragraph, including the parts of the stumps exceeding the height referred to in section 86 that are usable but are unharvested.
The volume of usable ligneous matter is the sound volume in a piece of timber up to the point where the diameter of that piece of timber becomes less than the minimum top diameter indicated in the annual management permit.