334 



AMERICAN FORESTRY 



per^isu-nt species reappear immediately after the fire in 



denser formations than before. Manzanita lias been 

 found to produce as high as 95 new shoots from a 

 single burned stump. ( Hher species of manzanita and 

 ehamise are prolific seeders, and the seed lives through 



HOW BRUSH FOLLOWS FIRE 



A stand of 91 seedlings to the square yard of manzanita has grown up where only one b 

 rod stood before the fire. Crater National Forest, Southern Oregon. 



the fire. Stands of 90 seedlings to the square yard have 

 been noted where but one bush to the square rod grew 

 before the fire. Ceanothus, rhododendron, and vine 

 maple, as well as most shrub species, survive these 

 periodic fires and form these 

 formidable thickets. 



While the brush areas repre- 

 sent the last stage of the forest, 

 they must also be considered as 

 advance agents of forest estab- 

 lishment. On severely exposed 

 slopes and in such regions as 

 southern Oregon the forest-tree 

 seedlings require some protec- 

 tion to become established. Strik- 

 ing examples are shown in the 

 establishment of yellow pine 

 seedlings in the Crater National 

 Forest in southern Oregon 

 where 95 per cent of the young 

 seedlings were found established 

 under hushes of ehamise and 

 manzanita. A brush cover not 

 only insures better moisture con- 

 ditions but also offers shade to 

 the young seedlings. An area 



which had not been burned for 20 years had a moisture 

 content of 6.2 per cent in the surface soil and 4.25 per 

 cent at a depth of 6 inches when it was examined during 

 the most severe dry period in August. This is sufficient 

 moisture for the establishment and growth of tree seed- 

 lings. An area burned one year previous to the exami- 



nation had only .87 per cent of moisture in the surface 

 soil and 3 per cent at a depth of 6 inches. These data 

 show that seedlings could not become established on this 

 area because the moisture in the surface soil is less than 

 the seedlings require. In this way the brush gradually 

 prepares the way for the return 

 of the forest. To accomplish 

 this, however, fires must be kept 

 out. 



The final or seventh stage is 

 reached when all growth except 

 annuals and some grasses has 

 been distroyed by repeated fires. 

 The barren appearance of the 

 slopes and ridges has inspired 

 the too common name of "Bald 

 Mountain" in this region. These 

 mountains are monuments to the 

 menace of repeated fires, whether 

 these fires are started by intent 

 or through carelessness. Where 

 the fires have recurred in such 

 close succession as to destroy 

 shrubbery as well as forest 

 growth serious erosion has re- 

 sulted. These eroded slopes are 

 not only non-productive but 

 detrimental to the conservation and purity of the water 

 supply. The muddy waters are a serious menace to 

 irrigation projects because of the silt deposits that are 

 made in the reservoirs and ditches. Bv the exclusion of 



sh to the equare 



THE LAST LINE OF DEFENSE 



Erosion is held in check by the brush, but gullies have begun to form. 

 Crater National Forest, Southern Oregon. 



fire the conditions favorable to tree growth are gradually 

 re-established through the reclamation of the area by 

 brush. This is a necessary step in the succession of 

 plant life in this region a fact that has been demon- 

 strated by the establishment of tree seedlings under brush 

 and their failure to establish themselves in the open. Fire 



