56 STATE OF MICHIGAN. 



ing to improve the stand, had very carefully cut out the inferior and de- 

 fective trees, but to such an extent that the remaining stand was left in 

 a very unfavorable condition for development. 



The opening of the stand too freely checks the growth of the trees b;v 

 making the conditions less favorable for the retention of moisture, and 

 has, Avith many trees, the additional danger of checking their height 

 growth by permitting the development of the base of the crown, and in 

 some trees (e. g. Oaks) by the development of water sprouts on their 

 trunks. In many cases such thinnings as those result in the ultimate 

 death of the top of the tree. This, of course, occurs during some excep- 

 tionally dry time, and the weather conditions are usually blamed for it. 

 The loss of soil moisture as a result of overcutting is due to the increased 

 air motion at the soil surface and the admission of sufficient light to 

 stimulate the growtli of grass and other moisture- I'obbing weeds on the 

 forest floor. The excessive light (and heat) increases the oxidation of 

 the organic matter in the soil, thereby lowering its moisture-holding ca- 

 pacity, and raises the temperature, thereby increasing the direct evapo- 

 ration of moisture. 



If the trees of the stand are sufficiently matured to produce seed abun- 

 dantly, such an overcutting wi]l result in a natural reproduction of for- 

 est trees. Should the stand be nearly mature, this would be a desirable 

 condition, hut in all immature stands the harm done by the overcutting 

 is but very slowly repaired by nature. 



That overcutting in a woodlot open to the run of live stock should be 

 more serious where grazing is practiced than otherwise can be readily 

 appreciated. In the former case the absence of an undergrowth will 

 leave the soil wholly unprotected, and there will be no young trees to 

 develop to fill the gaps in the stand. 



A detailed discussion of the injuries due to grazing, fire, insects, and 

 other causes of injury common to Michigan woodlands would unduly 

 lengthen an article already too long, and must be deferred for the present. 

 Suffice to say, it is the intention of the bureau to publish at an early day 

 a somewhat extended account of a study of woodlot conditions in South- 

 ern :Micliigan,, which will be available for general distribution. 



