few years for cutting up small amounts of lumber. However, where 

 the plantation is large enough, the lumber can be used profitably for 

 rough construction work on the farm. Round, split or sawed fence 

 posts made from cottonwood trees will last for 25 years if given a 

 good treatment with creosote.* In most sections of the state the 

 wood has a ready value for fuel on the farm. 



Soft Maple: Soft maple trees are quite tolerant of shade and, 

 consequently, grow in a dense stand. The dense shading on the 

 interior of the average soft maple grove makes it impossible to grow 

 successfully under the old stand any except the most shade-enduring 

 trees. However, under the regeneration method just described, the 

 new trees are established outside of the grove proper, where shading 

 interferes but little. Like the cottonwood, the soft maple is a short- 

 lived tree and regeneration by this method should begin by or be- 

 fore the fortieth year if possible. 



The relatively small number of maple trees removed periodically 

 under this system should generally be used for fuel or fence posts. 

 Soft maple fence posts when given a treatment of creosote, at a cost 

 of 10 to 15 cents per post, will last for a period of 25 years. 



Willow: The willow is also short-lived and the application of this 

 method should be begun preferably before the trees are 35 years old. 

 The willow sprouts persistently from the stump after the trees are cut 

 down and usually considerable trouble is experienced in killing the 

 sprouts. If the trees are cut in August, instead of in the winter, very 

 few sprouts appear, and if these are promptly removed the stumps 

 soon die. Under present conditions the willow has few uses except 

 for fuel. However, after treatment with creosote, willow fence posts 

 last for a long period of years and the wood from the old shelterbelt 

 might profitably be used for this purpose. 



Boxelder: Boxelder trees, although moderately rapid in growth, 

 are always crooked, of small size and very short lived. They have 

 little value except for wind protection. The regeneration by the 

 method just described, should be begun as early as possible, even in 

 young plantations. In old plantations (35 years), it is sometimes 

 desirable to renew the grove by a quicker method, such as the clear- 

 cutting system (see figs. 11, 12, 13 and 14). Use the trees removed for 

 fuel or, if straight enough, for fence posts. Posts treated with creosote 

 last as well as the cottonwood, soft maple and willow after treatment. 



TREES ADAPTED FOR PLANTING 



Practically any tree suited to the climatic, soil and moisture con- 

 ditions can be safely regenerated under this first system. The selec- 

 tion of the variety or varieties to be used must be largely governed 

 by the uses to which the shelterbelt is to be put and also by the likes 

 and dislikes of the owner. If the new grove is to serve efficiently as 

 a shelter from the winter winds, at least a portion of the new planting 

 should consist of evergreens. If it is to serve also as a source of 

 fuel, fence posts, and lumber, the trees best adapted for these pur- 

 poses should make up a part of the new plantation. Care should be 

 exercised in mixing species, so as not to have a row of fast-growing 

 trees, such as some of the hardwoods, overtop and shade put pre- 

 viously planted rows of a slower growing, intolerant species such 

 as the Austrian, Scotch, or western yellow pines. 



The following evergreen trees, when only one species is used, are 

 adapted for planting in regeneration from one side: 



*See Bulletin 158, Iowa Agricultural Experiment Station. "The Preservative 

 Treatment of Fence Posts." 



