CHAPTER V 
CONTROL OF PHYSIOLOGICAL DISEASES AND 
TREATMENT OF MECHANICAL INJURIES 
— GENERAL CARE OF TREES 
2\UST as in all other cases, the ills to which trees 
are exposed are best met with the prescrip- 
tion of the old adage: “An ounce of prevention 
is worth a pound of cure.” 
Just as the physician insists upon sanitary conditions, as 
a means of preventing disease, so the tree doctor should 
insist upon securing the most favorable conditions of growth 
for his charges. These may be achieved by looking after 
soil conditions, mainly with reference to air and water-sup- 
ply; by providing a satisfactory amount of light, and, above 
all, by timely and judicious surgery—pruning, by which the 
consumption of supplies from the root can be regulated 
sometimes more easily than the supply in the soil itself. 
These two means, then, regulation of foliage development 
by pruning and soil improvement, are compensating and 
should usually go hand in hand. ‘Timely attention to these 
requirements will prevent many of the troubles to which 
trees are liable, and, when trouble has come, half the battle 
is won, if these conditions of favorable nutrition are estab- 
lished and the tree has been kept in vigor to fight off the 
disease. 
We shall devote this chapter, therefore, entirely io the 
discussion of proper care in soil conditions and in pruning, 
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