110 TILE DRAINAGE. 



IS THERE DANGER FROM TREE -ROOTS? 



Yes, great danger under the same conditions as in the case of 

 cereals. The roots of aquatic, or water-loving trees, like the 

 willow and some kinds or elm, seem to have almost no limit to 

 their growth, either horizontally or vertically ; and they seem to 

 go in search of moisture or richness as if by instinct, and to know 

 just where to find it. I have traced the roots of a smallish elm 

 some 25 feet horizontally, and 6 feet vertically, to their feeding- 

 place in a grave in an old cemetery; and I have, in plowing, 

 traced the roots of a large elm one hundred feet horizontally by 

 measurement. These roots will enter even a tk pin-hole" in tiles, 

 if they can find running water. Mr. H. B. Camp, of Cuyahoga 

 Falls, O., told me a few days since that he once helped to take up 

 an obstracted drain whose joints were laid in cement, I think he 

 said. At all events, a willow root had entered at a pin-hol6 not 

 larger than a small darning-needle, and spread into a fibrous 

 mass and packed the tile full of roots for several feet the only 

 connection with the upper world and their lungs (the leaves of 

 the tree) being this small, threadlike root that entered at the 

 pin-hole. It is better to cut such trees down when they are near 

 a damp drain, and see that they are dead. Prof. Townshend, of 

 the Ohio Agricultural College, Columbus, exhibited in one of his 

 lectures last winter a dark, stiff, fibrous, spongelike, solid cylinder, 

 some three feet long and three inches in diameter. When the 

 class had doftfe guessing, he gave its history. It was the irillmr- 

 root core of his cellar-drain. Knowing the nature of these roots 

 he cut the willow down before he laid the drain, and burned the 

 stump all he could ; but in spite of that, its roots stopped his 

 cellar-drain at a depth of five or six feet. 



My experience and observation lead me to these conclusions : 



1. In ordinary cases there is no danger from roots; and very 

 hard-burned and even glazed tiles should be used, the water 

 entering at the joints. Hard tiles are more durable. 



2. Where there is danger from roots, as in the cases described 

 above, soft, porous tiles should be used, with joints laid in cement. 

 They may not last so long, but they seem to be the only kind that 

 will admit water and exclude roots. [See the note above.] 



3. Mere "collars" without cement will not exclude roots alto- 

 gether, and great care must be taken to use no tiles that have 

 pin-holes in them. 



4. A uniform grade is important, or at least there must be no 

 " up grade " between the head and the outlet. It will probably 

 cause permanent stoppage. 



the word of writers who claimed to have done so. Very thorough 

 experiments since made, and reported in Chapter VII. (pages 7^76 ), 

 seemed to prove that water will not enter a drain made as advised , viz., 

 with soft-baked tiles and cemented joints, fast enough to amount to 

 any thing-. Of this, again at the close of the quotation. 



