135. 



cU Pole sta^e, 30-50* high: At the end of this staje the crowns 

 begin to open up. In intolerant species the stand itself opens up. The 

 crown is even higher than in the preceding stn^e. The maximum growth per 

 acre of the stand has "been reached and pa; sed in this stage. Litter and 

 leaves are not so -bundn.nt. Roots are larger and/ interfere. 



Results of this stage: 



1) Less perfect use of soil. 



2) Greater air movement, therefore more drying out of soil. 



3) Wore rain .riving thru cover, which tends .to harden soil. 

 4} Diffused light mostly at ground. 



5) Temperature effect is more pronounced; i.e., lower and 

 more uniform than outside. 



Maximum growth, mulch and cleaning, root development and fertilit 

 drain on land and loss of isHtsr and redistribution of salts. 



. Tree stage proper, 60-100 years and over. 



The intolerant stand opens up decidedly. 3^~50^ of the la 

 is opened up to the rain, sun and wind. The crown opens up more decidedl 

 Th/e trees are teller; the canopy is higher, and gets the effects that 

 go along with it. Growth in height and volume per acre haa fallen off. 

 Weeds are apt to core i ;, etc. 



ffect on soil is: 

 1) Hardened. 



Dried out. 

 Less mulch 

 Less life (bacteria, fungi) 



5) Less tilth by roots 



6) Only partial use of soil, less demand on soil 



7) On account of decrease in growth, less demand for salts and 

 WR t er . 



hese effects are more pronounced in open stands. Old stands are 

 less able to take care of the lands than younger ones. 



Ji. Special Cases of Forests. 



When forest trees are unable to compete with and suppress fore 

 growth, weeds, grass, bushes, etc., come in. The soil is affected more 

 by the undergrowth than by the trees themselves. 



;a. Grass and weed cover on good soil, especially in cases of 

 reforestation of farm lands, yellow pine areas, in parks of the Rocky 

 ? ountains. The effect of the grass 6f to form a sod which consists of a 

 dense mass of roots limited to the upper 6 inches. This hardens and drie 

 out the upper layers. 



On good land grass does not exhaust plant foods, but it does draw 

 upon the water. In dry and cold situations this effect may become very 

 gr t. The chief harm is that it checks reproduction. 



^. &OBS cover. There are two groups: 



1) Ordinary moss. 



2) Sphafflium moss . 



Ordinary moss is not injurious; it prevents hardening of the soil 

 from rain impact and keeps the soil cool. In a cold climate, however, 

 keeping the soil cocl may check the bacteria, thus leading to a duff for 

 mation. 



