VEGETATIONAL ANALYSIS 



61 



nity. If quadrats are enlarged, classes A and E will enlarge and the 

 lesser classes will decrease accordingly. Frequency classes, there- 

 fore, are comparable only when based upon samples of the same 

 size. 



A frequency diagram is useful in indicating the homogeneity of 

 a stand since floristic uniformity varies directly with the values for 



80 



50 



% 



ABODE 



Raunkiaer's 



NORMAL 



ABODE 



Kenoyer's 



NORMAL 



15 YR. 



abode abode abode 



Loblolly Pine Stands-3ages 



eo 



50 



25 



% 



_n 



_□ 



ABODE abode abode abode abode 



Five Stands Virgin Red Fir- Sierra Nevada 

 FlG. 25. Frequency diagrams of pine stands of different ages and of virgin 

 red fir stands compared with Raunkiaer's and Kenoyer's normals. The pine 

 stands were all relatively homogeneous but became slightly less so with age 

 as the total number of species increased by 25 percent and the accidentals de- 

 clined. Class E, the dominants, remained essentially constant throughout the 

 series. All the virgin red fir stands were extremely homogeneous in spite of 

 a high proportion of incidentals occurring sporadically. The stands were also 

 similar to each other although widely distributed along the Sierra. 



classes A and E. When classes B, C, and D are relatively high, the 

 stand is not homogeneous. In general, the higher Class E may be, 

 the greater the homogeneity. 



Cover and Space.— Although density and frequency indicate 

 numbers and distribution, they do not indicate size, volume of 

 space occupied, or amount of ground covered or shaded. These 

 characteristics are desirable additional values that contribute ma- 

 terially to an understanding of the importance of a species in a 

 stand, since they are closely related to dominance. 



As suggested under Quadrat Methods (Chap. 3), cover can be 



