THE GARDENERS' CHRONICLE OF AMERICA. 



903 



comes poorer, the lower branches appropnaic must of 

 the food and the water supply at the expense of the 

 upper ones. Starvation may also come about front 

 excessively dry summers. This results in the dying of 

 many of the upper feeding roots. Proper nutrition of 

 the tree is interfered with, and starvation begins. 

 There is but one thing to do to avoid starvation, and 

 that is to feed the tree judiciously every year. A good 

 mulch of straw or rotted manure applied below the 

 outer branches or even a copious watering twice a 

 week will prevent starvation, which may result from 

 excessive hot and dry spells. 



As a rule, most attention and interest is paid to the 

 external parts of a tree or shrub. The needs and 

 wants of the roots are often ignored. It is true that 

 plants derive their starchy food from the air through 

 the leaves, yet no tree can live without its roots. 

 These supply the mineral matter and the water which 

 are the foundation of all plant life. Little do we real- 

 ize the work which the roots are accomplishing to 

 supply the wants of the leaves, stems and fruits. Roots 

 of plants do not often find the soil congenial in which 

 they are forced to grow. They must, of course, adapt 

 themselves to it or die. In this struggle, there is noth- 

 ing that works so much to their detriment than lack 

 of air in the soil. Poorly drained lands are not only 

 sour, but also are void of air, because of the water 

 which takes its place. Under these conditions, the 

 roots not only fail to perform their duties, btit they 

 also suffocate. Suffocation is often a condition peculiar 

 to shade trees which grow in city streets. There, no 

 cultivating space is allowed for the tree, which is stuck 

 in a tiny hole with large pavements on top which pre- 

 vent the free interchange of air to the soil. 



The symptoms of suffocation are cessation of growth, 

 a languid appearance, yellowing and premature falling 

 of the leaves, causing slow death. The same trouble 

 may result where young trees are planted too deep. 

 The roots rot, the tree remains stunted and dies pre- 

 maturely. 



The condition of drying out is different than stag 

 head. In dry weather, the trees or shrubs usually 

 make a rapid growth and produce tender foliage. 

 When the wet spell is followed by a hot and dry at- 

 mosphere, particularly when it lasts for any length 

 of time, there is a great evaporation of water through 

 the leaves which the roots are unable to supply. The 

 result is a general drying out of the leaves and some- 

 times of the entire tree. This condition occurs most 

 frequently in the West and Southwest. In fact, it 

 occurs under any condition which causes rapid evapo- 

 ration and where the roots cannot replace the loss fast 

 enough. 



Drying out also occurs in the winter where many 

 evergreens are killed. Here drying is caused by dry, 

 cold winds which may sweep over the country. 



Injuries from freezing are akin to those of drying. 

 Freezing often causes great damage to trees with 

 smooth bark. The injury is usually confined to the 

 trunk and branches which have the southwestern ex- 

 posure. The more succulent and tender growth the 

 trees or shrubs posses, the more subject are they to 

 freezing. 



Often long continued warm spells may induce sap 

 activity, swelling of the buds and even slight growth. 

 When this is followed by freezing weather greater 

 injury is apt to result. 



Today illuminating gas is used more extensive!}' 

 than formerly. Most cities and towns arc underwoven 

 with a network of pipes which carry the gas from the 

 factory to the consumer. Leakage from these pipes 



may be uf frequent occurrence. Heavy traffic, tearing 

 up of roads, or severe freezes, these, separately or 

 combined, may be the cause of leaky pipes. If the 

 leakage is weak, slight injury may result. However, 

 where the leakage is intense, it may mean death of the 

 tree. The symptoms of gas poisoning are very pro- 

 nounced in the summer. The first effect is a yellowing 

 of the foliage followed by an early defoliation, which 

 varies with the degree of poisoning. The trunk and 

 limb of the affected tree generally present a darkened 

 appearance, indicating absence of life. 



Trees killed by gas become very brittle and disin- 

 tegrate, thus becoming a source of danger through its 

 falling limbs. Undoubtedly trees adapt themselves to 

 a certain amount of poison in the soil, but the roots 

 cannot long withstand the effect of gas. 



In discussing fungus diseases, w6 are dealing with 

 a low form of plant growth which ordinarily lives on 

 decaying vegetable matter, but assumes a parasitic 



FUXGI ROT. 



PRODUCED BY GNAWING 

 OF HORSES. 



habit whenever wounds or injuries are inflicted to the 

 tree. Wounds are dangerous to woody plants or trees, 

 yet they are not always avoided. There are a number 

 of ways in which trees may be frequently wounded. 

 The common practice of tying horses to trees growing 

 in streets or lawns often results in the gnawing and 

 tearing of the bark. The death of such injured trees 

 is only a question of time, unless the wound is painted 

 over with some suitable paint, such as white lead or tar. 

 Winds al.so inflict their share of injury by breaking of 

 limbs or by causing abrasions through the rubbing 

 of branches which cross. Hollow trees are often pro- 

 duced by Iea\ing long stubs, resulting from poor prun- 

 ing. Decay starts on these stubs, which gradually 

 works its way into the trunk, this rotting out the heart 

 of the tree. If neglected, such trees are broken and 

 toppled over by winds. 



A great variety of trees often suft'er from the South- 

 ern root rot. The symptoms are sudden wilting of 

 the leaves with a gradual drj'ing up of the whole tree. 

 Upon examination, the tap roots are found dead, and 

 sometimes the entire root system decayed. The 

 trouble is induced by a fungus known as Ozonuim 

 Auricomum. This disease does most damage in wet 

 seasons, and in poorly drained lands. The disease is 

 confined largelv to the Southern and Southwestern 



