COMPUTING VOLUME AND DOSAGE FOR TENTED TREES. 25 



necessary to determine by an extensive series of experiments the 

 dosage required for different-sized trees for the various scale pests 

 infesting the citrus orchards. 



METHOD OF COMPUTING VOLUTVIE AND DOSAGE FOR TENTED TREES. 



Although most citrus trees possess a certain general similarity in 

 shape, they are nevertheless somewhat irregular, no two ever being 

 identical in all respects. This renders it impracticable to determine 

 the exact contents of any given tree. For field work, however, this 

 is unnecessary, and all that is needed is to approximate it with a 

 fair degree of accuracy. In order to calculate the cubic contents of 

 an object, it must be considered as shaped like some regular geomet- 

 rical figure or figures. The figure which most closely approximates 

 in shape an orange or lemon tree before it has been primed is a cylin- 

 der surmounted by a hemisphere, and in computing the volume we 

 have considered them of this shape. 



If we know the height and width of a tree covered with a tent, it 

 is a comparatively simple matter to calculate its contents. 



In the past in California work the dosage has been based upon 

 these two measurements. After a tree is covered with a tent it is a 

 matter of some difficulty to determine the height and the width. By 

 using as factors the distance around the bottom of the tent and the 

 longest distance over the top of the tent we arrive at a more prac- 

 ticable method by which to compute the cubic contents of a given 

 tree. Using these measurements as a basis the writer has invented 

 a formula ^ by means of which the cubic contents of a tree may be 

 computed. To avoid computation work in the field as far as possi- 

 ble, the writer has formulated a table approximating the cubic con- 

 tents of trees of different dimensions, which is, he believes, suffi- 

 ciently extensive to include any citrus tree in southern California. 

 During this investigation no tree has been found whose dimensions 

 did not fall within the limits given in this table. The distance 



a Professor Wood worth (Bui. 152, Univ. of Cal. Agr. Exp. Sta., p. 5, 1903) was the 

 first to propose a formula for obtaining the contents of tented trees by computing the 

 distance around the bottom and over the top. An analysis of this formula during 

 the early part of the writer's field work proved that it was inaccurate, thus necessi- 

 tating the determination of a new formula. The writer has worked out a formula 

 based on the two measurements above mentioned. It is as follows: 



CyO C(3;r-4) \ 



In this formula C=the circumference of the tree. 



0=the distance over the top of the tree. 



If a person works out and notes down in a chart the values of '^_ and — ^^^ — 



for different values of C of which he is apt to make common use, it is possible by its 

 use in connection vnth. the formula to determine the contents of trees with fair 

 rapidity. 



