STIti:i:T TREES. 



47 



the soil thoroughly and also to protect the top from the efTect of 

 drying winter winds. Where mice abound they may be harbored in 

 the mulch and may girdle the tree. This may be prevented by a 

 collar of wire netting about the base of the trunk or by banking the 

 earth about it. The death of trees at the time of transplanting is 

 due to the drying out of either roots or tops before opportunity is 

 given them to become reestablished in their new locations. This 

 drying may be due to improper exposure at the time of digging or 

 before packing (fig. 30), poor packing, prolonged delay in delivery, 

 improper handling between unpacking and planting, or the existence 

 of conditions conducive to excessive drying out of the plant after 

 setting. 



Fig. 32.— a city nursery. 



The atmosphere is continually claiming a tribute of moisture from 

 all living plants, whether the plant is in leaf and growing or is dor- 

 mant. Growing plants, and dormant plants under normal conditions, 

 are able to replace this moisture by absorption through the roots. In 

 climates where newly planted trees may obtain sufficient sod water 

 to replace these losses by drying, fall planting is best. Where the 

 plants are unable to get sufficient winter moisture, planting would 

 better be done only in the spring. Where the soil freezes to a depth 

 greater than that to which the plant roots extend, the supply of water 

 is cut off from the roots and the tree will be killed by drying out 

 through evaporation from the top. Where winter winds are very 

 drying and the soil moisture is limited, evaporation from the top is 

 likely to be in excess of that supplied by the roots and the tree is 

 killed m the same way. 



