TRANSECTS 



177 





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Fig. 55. Line transect running east 

 and west in the Picea-Piitus-hyliuin, 

 sliowing the relation of the herbaceous 

 layer to the Carex-Catha-helium, in- 

 vading along the brook; ecotones at e. 





plants is made entirely without reference 

 to the surface line. The vertical lines on 

 the centimeter sheet are taken to corre- 

 spond with the tape, and the individual 

 which touches the latter on either side is 

 recorded to the right or left respectively 

 and within the proper square. The spe- 

 cies are indicated as for quadrats. A 

 single row on either side may be taken 

 alone, but the double series serves as a 

 desirable check. After the record is 

 made, the topography of the transect is 

 drawn carefully to scale. This drawing 

 is made upon the scale of 100:1 for 

 transects of 10 meters or less, and of 

 1000:1 for those that are longer. The 

 combination of this drawing with the line 

 series of plants can not be made advan- 

 tageously in the field. For the shorter 

 transects, meter sizes of centimeter plot- 

 ting paper can often be used to advan- 

 tage. In this event, the topographic line 

 is drawn to the scale of 10:1 and the 

 series of plants transferred directly to it. 

 In the case of transects between 10 and 

 100 meters, the scale of the drawing is 

 increased from 1000:1 to 100:1, so that 

 each decimeter of the original series is 

 compressed into a centimeter. For the 

 longest transects, corresponding reduc- 

 tions must be made, but in these it will 

 be remembered that the series is plotted 

 by meter instead of decimeter. 



219. The location and size of line 

 transects are determined by the purpose 

 for which they are designed. Short 

 transects are valuable for detail, but they 

 can be used to advantage only where 



