984 JOURNAL OF FORKSTRY 



badly burned, hence lacking in many of the soil constituents essential 

 for the best development of the more valuable species. The geological 

 formation of this region is such that although the rainfall is heavy 

 those slopes unprotected by a timber covering dry out rapidly. The 

 alder, as it ascends these slopes, creates a better moisture condition of 

 the soil because of its presence. Hence, taking everything into consid- 

 eration, the red alder, although a species of comparatively small value, 

 is creating a condition enabling the more valuable Douglas fir to regain 

 a foothold, so that ultimately those large areas now barren will revert 

 to the immense forests which once covered the region and not only 

 create an asset of great economic value, but also one of esthetic value 

 to the people as well. 



2. Its Value as a Soil Builder 



The value of alder as a soil builder has been touched upon under the 

 previous heading, but only to a slight extent. Its importance in this 

 respect has been realized in part by many ; but to what extent it has 

 added to the economic value of lands within and adjacent to the Sius- 

 law Forest has never been fully appreciated. It is safe to say that 

 many of the prosperous dairy communities on the Oregon coast would 

 not have been possible but for the presence of this species. The greater 

 the development and prosperity of the communities adjacent to and 

 within the Forest the greater will be the increase of transportation 

 facilities, hence larger the market and greater the value of forest 

 products. 



The influence of alder growth on the soil is twofold in that it affects 

 both the physical condition and the chemical properties of the sites 

 upon which it grows. 



One of the most notable effects is the presence of abundant moisture 

 in the surface soil upon passing from the open areas into the alder 

 growth. The alder is naturally a moisture-loving species and upon 

 moist bottoms its root system is shallow. However, as it advances 

 upon the drier slopes the roots must necessarily seek water at greater 

 depths. The effect of this is to render the soil more friable, hence the 

 moisture of the lower soil strata is rendered available to the surface 

 roots through increased capillary action. This, together with the less 

 loss through evaporation, accounts for the greater moisture content of 

 the soil under alder growth. In this same respect the mulch created 

 under the alder through the accumulation and decaying of debris acts 

 as a moisture conserver. This also greatly enriches the soil through 

 the formation of humus. 



