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the weeds and briars and rapidly establishes a good stand. Should other 

 species than those present be desired it is necessary to plant them. As 

 soon as reproduction is well under way the mature trees may be cut 

 Still it is a wise plan to leave some of them for seed and to furnish timber 

 while the new crop is growing. 



IRREGULAR, USJEVEN-AGED STANDS. 



Character. — It is from the irregular, uneven-aged stands that we ex- 

 pect the earliest good results. These are parts of the original forest re- 

 tained in almost virgin condition. Some are dense, others more or less 

 open. In them the soil is almost ideal, but not so with the forest. Fun- 

 gous and insect hosts, old logs in various stages of decay, are scattered 

 over the ground. Many of the trees are mature but in very poor condi- 

 tion. Some, however, are large and have long, smooth trunks and com- 

 pact crowns. Increase in height has practically ceased and diameter 

 growth is very slow. A young growth of various species, many of which 

 are undesirable, fills up small openings made by fallen trees. On the 

 whole the forest capital is slowly but surely decreasing, for the amount 

 of timber produced annually is more than offset by death and deteriora- 

 tion of the overmature trees. 



Improvement. — The first requirement for the improvement of this type 

 is the same as for mature open stands ; that is, the removal of tree weeds 

 and the species undesirable for other reasons. The next process, thinning, 

 is brought about naturally by shading. Trees which are crowded while 

 young try to get their crowns into sunlight, and consequently produce long, 

 slender stems. If, after a sufficient height has been reached, space is 

 given for increased root and foliage development, an increase in wood pro- 

 duction occurs. This increase takes place in diameter growth, since there 

 is no longer any incentive for height growth. The purpose of artificial 

 thinning is. then, to accelerate diameter growth as much as possible, to 

 substitute for nature's wasteful struggle a systematic removal of weaker 

 and inferior trees, leaving as many of the good ones as can develop with- 

 out retardation for a given period. 



Thinning. — This process requires considerable judgment and experi- 

 ence, for special attention is given to the trees which are to remain rather 

 than to those which are to be cut. Of course the most valuable and rapid 

 growing species take precedence over others. The following list will serve 

 as a guide, although it is by no means invariable : 



