1922] HARVEY—PINE FORMATION 39 
It has been noted that the influence of oft repeated fires regulates 
the “presence or absence and nature of the shrubby and herbace- 
ous layers.” The large percentage of hemicryptophytes and 
geophytes in a forest formation are thought to be in large part an 
expression of this influence. 
Valences 
The biological spectrum furnishes one of the essentials in the 
ecological characterization of a formation. ‘The method of valences 
also offers an objective means of presenting an equally important 
picture, that of the numerical abundance of the various floristic 
elements of the formation. It is the frequency percentage of the 
TABLE VI 
PERCENTAGES OF GROWTH FORMS IN BIOLOGICAL SPECTRA 
Type of growthform | MG | MS | Mc | N | CH | H o | RE Le 
Ce ine ° 7 II 18 II 24 27 2 
abate ga 7 17 20 G03) a7 3 I 13 
New York City. . Oo | 1.31 | 3.04 | 8.55 | 8.55 [26.32 [24.34 | 23 | 3-04 
various elements which determines the aspect of the formation or 
its physiognomic character. 
Various methods have been employed since the introduction 
of the quadrat method in such statistical investigation. The 
method used in this study in an adaptation of that used by 
RAUNKIAER.S As only the facies was considered, it was possible 
to devise a rapid method of record. A rope 5 m. long held in the 
hand of an assistant formed the radius of a circle whose species 
were recorded as the investigator moved the radius through 360°. 
The center of the next area was obtained by swinging the radius 
through 180°, and with this as a fixed point the assistant then took 
his stand 5 m. farther on in the same axis. Thus areas are tangent 
to each other. In this way a transect of 200m. was run. The 
valence records are thus based upon twenty such areas (table VII). 
‘ For accounts of RAUNKIAER’s work see: SmiTH, W. G., RAUNKIAER’s life forms, 
and Hagia methods. Jour. Ecol. 1:16~26. 1913; and FuLter, G. D.,and BAKKE, 
L., RAUNKIAER’s “life forms,” “leaf ear and wateael methods. Plant 
World 2125-37. 1918. 
