41 



Fig. 8. A windbreak composed of western yellow pine (left) and Black 

 Hills spruce (right.) The trees are all about ten years old. Note the relatively 

 slow growth of the spruce. 



while that on young ones has a more blackish color. The trees 

 are very intolerant of shade, except when young. The crowns 

 are quite dense in youth but become more open as the trees 

 increase in size. The foliage is coarse in appearance and some- 

 what resembles that of the red pine. The needles are some- 

 times 8 inches in length. 



This pine has been planted extensively in the western part 

 of the country. The seedlings develop a long tap root and 

 nursery stock, unless transplanted, is very difficult to handle 

 successfully. The initial growth of this pine in central Iowa is 

 considerably slower than the red pine but, without question, 

 it will resist drier situations than the latter after being suc- 

 cessfully planted. 



The Wood'. The wood is strong, rather light and is not 

 durable, except after treatment with a preservative. The tim- 

 ber is one of those most extensively used for lumber. 



Planting'. The western yellow pine is very serviceable for 

 windbreak and shelterbelt planting in Iowa. For this purpose 

 the trees should be spaced from 10 to 12 feet apart in the rows. 

 If more than one row is planted, it is often desirable to use also 

 a second species, such as the Norway spruce, which might make 

 up the interior portion of the windbreak. Use only well-rooted, 



