THE COAST FOREST 251 



Muir Glacier; with these soon appeared the ubiquitous 

 shrubby alder (A/nus simiata) and the feather-seeded 

 balm of Gilead, which, as they grew in height, crowded out 

 the light-needing willows ; then, some forty or fifty years 

 ago, a good seed year occurred in some neighboring forest 

 on the mainland, together with favorable wind conditions, 

 and at least the margin of the thicket of alders and 

 cottonwoods was sown to spruce. This shade-enduring, 

 yet rapid-growing and persistent species soon attained the 

 height of the low alders and shut in and finally killed the 

 light-needing cottonwoods, leaving only their dead and 

 decaying stumps and trunks as witnesses of their former 

 occupancy of the soil. Here and there a cottonwood has 

 persisted with its crown still in the sunlight a tall, 

 slender pole, clean of branches showing in the narrow 

 rings of the last years' growth that it is doomed soon to 

 succumb to its stronger neighbor. 



Meanwhile, this fringe of spruces forms an effectual 

 barrier to the dissemination of seeds in the interior from 

 outside sources and the light-needing species already 

 there will remain in undisturbed possession until the 

 spruces of the Point itself begin to bear seed freely; 

 finally, however, they must succumb to the more persist- 

 ent and shade-enduring spruce and hemlock, except where 

 soil conditions are too unfavorable for these species. Yet, 

 after their dominion is established, should the glacier 

 again advance, the same catastrophe may overcome the 

 victors as is revealed near Muir Glacier, in the uncover- 

 ing of a buried forest, established uncounted ages ago at 

 a different stage of glacial development a catastrophe, 

 the possibility of which is exemplified in many places, 

 where the push moraines are crowding upon the forest. 



Of the many other interesting observations on local dis- 

 tribution and the relation of tree growth to soil, only two 

 may be noted. The first refers to the presence of trees 



