ECOTONE CHARTS l8l 



meters of the sticks. These should be two meters high for woodland, and 

 one meter for grassland. Layer transects often run on even surfaces, but if 

 this is not the case, the usual data for a topographic map should be taken. 

 The final chart is constructed on the scale of io:i, the height of each plant 

 being indicated by a vertical line equal to .i of the observed height. A pho- 

 tograph of a representative meter of the transect is taken when the measur- 

 ing sticks and rods indicated above are in position. Physical factor read- 

 ings, principally of light, but often also of humidity, temperature, and wind 

 are made at the height of the various layers when these are present. 



ECOTONE CHARTS 



225. The contour lines of zones and consocies are of the utmost impor- 

 tance in recording the structure of vegetation. They do not permit such 

 accuracy as do quadrats and transects, but this is hardly to be considered a 

 disadvantage in view of the fact that ccotones are rarely sharply defined. 

 In establishing the ecotones of zonation, the width and the length of the 

 base, i. e., the area of excess or deficiency, or as much of it as is to be con- 

 sidered, are determined. This base may be road, ditch, pool, lake, or stream, 

 or the peak or crest of a hill, ridge, or mountain. When the zonation is 

 bilateral, meter tapes are run at right angles to the base, at proper intervals, 

 and the points and the distances where the ecotones cross are noted. In the 

 case of radial zones, the tapes are run in the four cardinal directions, and 

 if the base be large, in the four intermediate ones also, the intersections 

 being likewise noted. From the data thus obtained, the zones may be out- 

 lined with a fair degree of accuracy. If the series be an extensive one, it is 

 charted to the scale of ioo:i ; in cases of small areas, however, the scale of 

 io:i will give better results. Whenever the zones show clearly enough to 

 warrant, a photograph is also taken. Water-content readings are of para- 

 mount importance in the interpretation of zones. Samples should be taken 

 at all intersections, and the resulting values indicated at the corresponding 

 points upon the chart. When the zones are broken up into alternating 

 patches in consequence of asymmetry in the topography, the ecotones of the 

 latter are traced in a similar fashion from the center of each as a base, 

 the absolute position of which is ultimately determined with reference to 

 the ecotone lines already established. 



