SUMMARY. 



Stem form investigations. 



This work constitutes a summary of investigations which have bearing 

 upon the enlightenment of the factors we have to deal with as they apply 

 to the taper of trees. In order to get a unified view point of these investi- 

 gations, an actual problem has been chosen so that the different factors 

 might be studied with reference to what measure they influence the possibili- 

 ties of estimating the log yields of different dimensions for standing trees. 



In Sweden two different methods of estimating are used, the ptirely ocular 

 method being left out of the reckoning. The one method of getting the 

 yield within a forest is carried out by the use of calipers giving the diame- 

 ter of the first log at 17 to 21 feet above the ground. The rest of the 

 logs are estimated by eye. This method can easily take into consideration 

 deficiencies such as crooks, rots, etc. which neccesitate a change in the log 

 division. 



The other method called the Form Class Method is built on the averages 

 for the stånd, with respect to form class, height, bark thickness etc. In this 

 way one gets a statement regarding the sample trees and can reckon the 

 log division in the office. With either method one has a reckoning of the 

 total number of trees in the different diameter classes (diameter at breast 

 height outside bark) which are to be utilized. 



All över where forests are to be sold on the stump one or the other 

 method must be used to determine their value. Logs pay difterently accor- 

 ding to their dimensions and these are formulated into price lists which 

 difter in different parts of the country and for different species. Thus being 

 familiar with which logs can be taken out of the forest, one can' reckon 

 their total value after which the sale price can be determined by subtracting 

 the costs of cutting and transport. 



Methods using calipers are very expensive because such a great number 

 of sample trees is necessary when one studies the individual stems, so it 

 would seem advisable to use the form class method, which relies upon 

 averages. I will explain the possibility the latter method gives and I shall 

 in turn and in order investigate the factors whereupon_the accuracy of the 

 method depends. 



Form class method. Orientation. 



Estimating notes refering to the number of trees should be divided into 

 diameter classes calipered outside bark, with group intervals, for instance of 

 I inch. In order to reckon the yield of timber we must not only know 

 the diameter breast height but also the taper in respect to the diameter 

 at breast height. The bark thickness should be excluded since only the 

 wood is of value. Therefore on sample trees one must know the bark thick- 



