VEGETATIONAL ANALYSIS 44 



he was able to relocate these points exactly, and he obtained a 

 striking series of matched pictures illustrating the development of 

 each of the vegetation types on the island. 74 A number of similar 

 illustrations could be mentioned, but they are far too few. 



Marking such plots when far afield may be something of a 

 problem, but by forehanded thoughtfulness combined with in- 

 genuity an adequate plan can usually be devised. A small can of 

 paint is no great burden when added to regular field equipment, 

 and its judicious use in conjunction with blazed trees, rock cairns, 

 or the like will usually suffice (see Fig. 11). It should be added 

 that experience indicates the advisability of recording in one's 

 notes a careful description of the markers and their exact posi- 

 tion with reference to landmarks of a permanent nature. 



Quadrats originally set up for permanent study are usually of 

 an experimental nature. Perhaps they are to be subject to a treat- 

 ment of some sort, as, for example, different degrees of grazing, 

 watering, or thinning. For acceptable results these must always be 

 laid out in pairs so that an untreated plot can be used as a check 

 or control on the treated area. Usually it is desirable to replicate 

 the pairs one or more times, and this must be given serious thought 

 in terms of the extent of the stand and uniformity of conditions. 

 Such experimental areas are often established near at hand and in 

 easily accessible places, for they are to be visited regularly. With 

 plans made in advance, materials for permanent marking are among 

 the first equipment to be assembled. Substantial lengths of old pipe 

 or scrap metal, when driven into the ground leaving a few inches 

 protruding, are permanent and very satisfactory markers. If they 

 are painted conspicuously and marked with numbers, there can be 

 no confusion. 



Experimental quadrats are of many types. Studies of competi- 

 tion and survival may involve thinning of stands, eliminating unde- 

 sirable species, or introducing other species, either by seeding or 

 planting seedlings, the object being to observe effects on the com- 

 munity or the introduced species. Newly exposed bare areas may 

 be studied to follow the natural development of vegetation, or 

 areas may be denuded and attempts made to produce artificial 

 communities. Perhaps the quadrats are used to evaluate the effects 

 of some controlled factor such as artificial watering or shading or 



