54 the study OF plant communities ■ Chapter HI 



forest and grassland. 139 These surveyors' "transects" were some of 

 the first and longest ever run. 



Sometimes there is an advantage in the use of "line transects" in 

 which the species are tabulated as they occur along a line. The 

 method is adaptable to the determination of numerical abundance, 

 frequency, coverage, and other characteristics. It has the advan- 

 tage of speed and apparently gives accurate information, consider- 

 ing the time it requires. It is particularly useful in dense stands of 

 scrubby vegetation, which would be very difficult to sample with 

 quadrats. Determinations of cover in dense chaparral using line 

 transects gave results that compared very favorably with those ob- 

 tained by complete charting, although the transects were made in 

 a small fraction of the time required for the detailed procedure. 13 



r-130 



-loo 



Rain Forest Swamp Forest 



Fig. 23. Profile diagrams (bisects) of two types of tropical forest. Note 

 that difference in height of trees and in form of trunk is well shown and that 

 rain forest has three distinct strata of trees but swamp forest has essentially 

 one.— After Beard. 15 



Bisects.— These are variations of transects in that they are sam- 

 ple strips aiming to show the vertical distribution of vegetation. 

 Thus they may include stratification and layer communities from 

 dominant trees to seedlings on the forest floor and, in addition, 

 show the stratification and root distribution of these same plants 

 below ground. 



GENERAL REFERENCES 



S. A. CAIN. The Species- Area Curve. 



S. A. CAIN. Sample-Plot Technique Applied to Alpine Vegetation in Wyo. 

 F. X. Schumacher and R. A. Chapman. Sampling Methods in Forestry 

 and Range Management. 



