APPLICATION OF PHYTOSOCIOLOGICAL TECHNIQUES 



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Table 10. Tree species having Raunkiaerian class D and E frequencies on a sample 

 plot of equatorial rain forest at Mucambo 



Species 



Class E frequency 



Eschweilera odora 



Protium trif oliolatum 



Echweilera krukovii 



Tovomita stigtnatosa 



Vochysia guianensis 



Protiiim sp.? "Breu mescla" 



Iryanthera juruensis 



Theobroma subincana 



Class D frequency 



Protium nodidosutn 



Protium carnosuni 



Vantanea cupularis 



Protium puncticulatum 



Micropholis acutangula 



Osteophloeum platyspermum 



Sterculia pruriens 



Sapotaceae, Gen. sp.? 



Helicostylis peduncidata 

 Thyrsodium paraensis 



Combination of data. On a basis of the relative measures it is possible 

 to combine the different quantitative data available for the trees of the 

 Mucambo plot. The sum of the relative density, relative dominance, and 

 relative frequency of a species may be referred to as the importance value 

 index (Curtis and Mcintosh, 1951). Since these are percentage data, the 

 sum of all indexes would be 300. 



Table 11 gives the importance value index for each species that attains 

 a value of 1 per cent or more in any of the series: density, dominance, or 

 frequency. There are only 44 of them, or about one-fourth of the total species 

 present on the plot. The leading species of the forest, by this combined 

 measure, is found to be Vochysia guianensis, with an index of 23.42. This 

 is the sum of 5.46 per cent relative density, 15.05 per cent relative dominance, 

 and 2.91 per cent relative frequency. In this case it is seen that basal area 



