TRANSECTS 179 



as for the line transect, except that the record covers a decimeter strip just 

 as in quadrat work. Accordingly, an interval of a centimeter is left on the 

 sheet between the successive portions of the strip, in order that the latter 

 may be put together without confusion when the topographic map and the 

 plant series are combined. The record should invariably start in the upper 

 left-hand corner and read down. The map and the centimeter strip record- 

 ing the plants of the transect are combined on a common scale as already 

 indicated for the line transect. 



The ecotones of zones are shown on belt transects by single cross lines, 

 and those of consocies by parallel cross lines. In taking photographs of the 

 transect, it is desirable to use guidons to mark these points clearly. The 

 same device may also be used to indicate the course of the transect, when the 

 tapes are completely hidden by the plants. Physical factor readings should 

 always be taken, and, as before, they are best made at the intersections of the 

 ecotones. 



The Permanent Transect 



221. Advantages. Both line and belt transects, after they have been re- 

 corded, should be rendered permanent, in order that they may serve to indi- 

 cate the changes of a heterogeneous area from year to year in the same 

 detailed fashion that the permanent quadrat does for homogeneous ones. 

 For historical as well as for physical reasons, the ecotones of zones and of 

 consocies are subject to change from year to year, and the amount and di- 

 rection of this change can only be ascertained from annual records made in 

 exactly the same spot. By means of the permanent transect alone the very 

 origin of such areas can be followed from one stage to another of the suc- 

 cession. Moreover, the transect is equally valuable with the quadrat in 

 making it possible to follow every step of the minute changes wrought by 

 competition. 



222. Details. The transect is made permanent by blazing the landmarks 

 at either end, if these already exist, or by erecting them when it is necessary. 

 A label stake is driven at each end, on which is painted the number and date 

 of the transect and its length. Each stake should also indicate the exact di- 

 rection in which the other lies. The position of the ecotone is indicated by 

 smaller stakes bearing the number of the transect and the date when the 

 ecotone was found at that point. These are left in place, and in a few years 

 show very graphically the change in position of the zones. For the first 

 season, permanent transects afi"ord results of great value when recorded for 

 each aspect, but after this an annual visit will suffice. The details of map- 

 ping, plotting, etc., are identical with those indicated above, with the addition 



