54 



dug up and the roots removed the drain had been in operation 

 seven years, although a cross-section of the root and an examina- 

 tion of the annular rings where it entered the tile, showed that 

 it was only five years old. It required, therefore, only five years 

 for this mass of roots to clog up a 12-inch tile. 



The maximum diameter of this mass of roots in the dry state 

 is six or seven inches, but when alive and flourishing in the tile 

 its diameter exceeded this. The roots as they reached the 

 laboratory had a decidedly bad odor, showing that if no sewage 

 was present in the tile there was certainly a considerable amount 

 of organic matter in the seepage derived from the soil or some 

 other source which proved of value as plant food. Soon after 

 the specimens arrived at this laboratory they were spread out 

 on the floor and measured. This was done by laying out on the 

 floor sections five feet in length. The number of roots in each 

 five- foot section was counted. These were multiplied by the 

 length of the section and the whole tabulated (see table). The 

 total length of these roots was 8,498 feet, as shown in the table, 

 which is equal to 1.61 miles. Adding to this the numerous small 

 roots which range from a few to several inches in length and which 

 were not considered in our section count, the total length was 

 estimated to be over two miles. 



This enormous development from a single root of a pear tree 

 is greatly in excess of what would take place if the roots were 



Table Showing the Growth of Pear Tree Roots in Drain Tile 



No. of Section. 



Length of Section. 



No. of Roots in 

 Section. 



Leng-th of Roots in 

 Section. 



I 



5 ft. 



34 



170 ft. 



2 



5 



41 



205 



3 



5 



73 



365 



4 



5 



153 



765 



5 



5 



199 



995 



6 



5 



313 



1565 



7 



5 



373 



1865 



8 



5 



447 



2235 



9 



5 



141 



705 



10 



5 



53 



26s 



II 



5 



31 



155 



12 



5 



36 



180 



13 



I 



28 



28 



Total 



61 



1922 



8498 



