T\T[NDBREAKS. 



It is decidedly unfortunate that blue gum can not be planted more 

 widely for windbreaks. If set out with an orchard, the windbreak 

 will easily keep ahead of the fruit trees. In most cases it will attain 

 a height of 50 feet or more in six years, and of 100 feet in ten years. 

 The great value of blue gum for windbreaks lies in the facts that it 

 grows very tall without taking up much ground, that it is firm 

 against all winds but tornadoes, and that its crown is flexible and 

 elastic, and, by bending, diverts the wind diagonally upward, instead 

 of offering a resistance that forces it to go through in strong currents. 

 On the other hand, there is the disadvantage that the clear trunks 

 offer little opposition to the wind near the ground. This, however, 

 is easily overcome by planting a close row of cedar or cypress next 

 to the gum. 



Blue gum windbreaks are most effective when composed of two 

 rows of trees set 4 feet apart in the following manner : 



o o o o o o 

 o o o o o o 



Many planters, however, are satisfied with a single row. 



The intervals between parallel windbreaks will vary according to 

 the character of the local winds, but in most parts of California it 

 is thought best to have them not more than 400 feet apart. The 

 trees may be obtained, planted, and cared for in the same way as 

 those in woodlots. 



Either Monterey cypress or Italian cypress is recommended for 

 the lower part of a composite windbreak. Both grow quite rapidly 

 and will maintain a dense hedge to a height of from 30 to 40 feet. 

 One row of blue gum and one row of cypress are all that is necessary. 

 The latter may take the place of the leeward row of blue gums 

 indicated in the diagram above, though when the cypress trees are 

 about 10 feet high every other one should be removed, leaving 

 them 8 feet apart. The blue gums should be maintained with their 

 original spacing of 4 feet b}^ planting a new tree wherever one 

 dies. 



riRE. 



Every eucalyptus plantation must be carefully guarded from fire. 

 The fallen leaves, twigs, and bark shreds, which always cover the 

 ground to considerable depth, are naturalh^ oily, and in the dry air 

 of the Southwest become highly inflammable. If a fire once starts 

 it is almost impossible to put it out before the heat, if not the direct 

 flame, has killed or seriously injured the trees. The bark of the trees 

 is not thick, and affords little protection to the living tissue. 



[Cir. 59] • I 



