124 AGRICULTURE OF MAINE. 



the manufacture of starch and allow for the entrance of carbon 

 dioxide gas from the air which is absolutely essential for the 

 manufacture and production of starch, sugar and other carbon- 

 aceous compounds used in the nutrition and growth of the tree. 

 It will be seen that the loose, spongy nature of the leaf tissue 

 is adapted to these processes also. 



We are now ready to start with the simple food materials in the 

 soil which have been supplied by means of chemicals or which 

 have been produced by the breaking down of organic matter 

 in the soil and its conversion into available form by the soil 

 bacteria, and follow their course till they are built up into the 

 tissues of the tree. Tn the first place they must be in solution. 

 This requires the presence of an adeciuate supply of soil water 

 which may not be present during the diest summer months 

 unless evaporation has been retarded by means of frequent 

 cultivation. The root hairs give off an acid secretion and it is 

 generally thought that this assists in dissolving and bringing into 

 solution certain m.ineral food substances. 



Now having the plant food materials in available condition 

 and in solution, how does the apple tree take them up? The 

 natural answer is, by means of the roots, but if you press the 

 question farther and ask if all of the roots or only certain parts 

 of each root function in this matter I venture to state that the 

 average individual has rather hazy ideas on the subject. As a 

 matter of fact the entire process of absorption of these food 

 materials in solution takes place in a very limited portion of the 

 roots and is confined largely to the root hairs. Root hairs occur in 

 only one narrow zone and this is just back of the growing point 

 at the end of each and every tiny rootlet. Knowing this fact we 

 can appreciate how very important it is in transplanting trees 

 that these small rootlets are not broken off and are disturbed 

 as little as possible if the tree is to go on growing without a 

 serious setback. And knowing this fact also it is not at all 

 surprising that so many young orchards come to grief the first 

 year, and infant-tree mortality is so large. Another important 

 lesson which this fact teaches is that the man who distributes 

 his fertilizer only closely around the tree trunks could not 

 place it in a more inaccessible place so far as the majority of 

 the organs of absorption are concerned if he sat up nights and 

 worked over time trying to devise a means of so doing. Hence 



