THREE METHODS OF CALCULATIONOF THE YIELDFROM UNEVEN=AGED HIGH-FORESTS - For more than 40 years, the Forestry School of Nancy hashad, as a property for purposes of study, in the Vosges, an uneven-aged fir-forest divided into three working-sections.The "Rein-des-Boules" series of an area of 37ha 89;The "Corne-de-Lisse" series of an area of 34ha 01 ;The "Naufragoutte" series of an area of 34ha 48 .The rotation adopted for felling being of io years, each serieshas been divided into Io compartments so as to cover one ofthem in each series each year.The yield is calculated specially for each compartment byone of the following three methods :1) In the "Rein des Boules", the yield from a certain numberof trees, which has a big historical importance in France.2) In the "Corne de Lisse", the capability by volume-Massonsystem, much employed towards the middle of the last century.3) In the "Naufragoutte", the capability by volume-systemof the 1883 memorandum or official French system actually inforce.There was fixed first of all, based on averages collected bymeans of inventories, an "optimum" state, a well defined ideal,called "norme" which it was proposed to realise in all the compartments.The inventories which were made every No years served torecalculate the yield from each compartment at each rotationand allowed the evolution of the stands to be followed. After some hesitation, the stands were finally brought intothe normal state, and those that were there already kept there.Whatever method of calculation was adopted, this result hasbeen reached and the 3 series of the School actually constitutea very satisfactory type of uneven-aged firforest....