Southeastern Washington and Adjacent Idaho. 91 



tain streams, which, indeed, may be fringed with a more or less 

 fragmentary alder community. 



SUBSERE. REFORESTATION OF CUT-OVER AREAS AND 



BURNS 



Since the direction of development is always forward and 

 toward the climax community of a region, the removal of the 

 plant cover, such as a forest, makes possible the repetition of 

 the story of normal succession. This, however, may be consider- 

 ably modified and the amount of repetition determined by the 

 degree of completeness of the destruction. 



In studying the natural reforestation of the region, it will be 

 advantageous to consider first the secondary succession or sub- 

 sere after cutting, and afterwards the reestablishment of forests 

 following burns. 



Naturally many of the outlying pine-covered areas were early 

 cleared by the settlers and the land used for the cultivation of 

 crops. Where small tracts have been allowed to " go back " after 

 removing the yellow pine and burning the brush, the first years 

 show a rapid growth of shrubs while the intervening spaces are 

 dominated largely by prairie species. Opulaster pauciflorus, 

 Spiraea corymbosa and other shrubs, which in the denser stands 

 have been suppressed by the shade, spring rapidly into dominance, 

 while Epilobium angustifolium, Cirsium palousense, Pteridium 

 aquilinum pubescens, and Deschampsia spp. mingle with various 

 prairie species already designated as occurring in yellow pine 

 forests. Among these, yellow pine seedlings grow vigorously 

 and the forest finally reestablishes itself. Of course, repeated 

 fires kill the pine seedlings, burn off the shrubs, and favor the 

 invasion of prairie plants. Although prairie fires in the Palouse 

 Region were never so severe as those of the Great Plains, it is 

 probable that they played an important role in preventing the in- 

 vasion of conifers into the grass land. 



In most of the more accessible canyons of the mountains, 

 lumbering has been carried on and in some places the operation 

 of the lumberman has been followed by ground fires. In prac- 

 tically all cases, except in the lodgepole region eastward, where 



91 



