DEVELOPING FUNCTIONS TO ESTIMATE DENSITY AND GROWING SPACE INDEXES FOR Rhizophora apiculata Blume PLANTATIONS IN NGOC HIEN COASTAL AREA OF CA MAU PROVINCE

Abstract

SUMMARY

Plantation tending is an important task of silviculture to ensure that desirable individual trees receive adequate space, light, water, and nutrients necessary to thrive. This study aims to develop functions for the rapid estimation of density and growth space indices for Rhizophora apiculata plantations in the Ngoc Hien coastal area of Ca Mau province. Research data were collected in R. apiculata plantations from 10 to 25 years olds; in which each age group was 3 standard plots with an area of ​​400m². The density index (SDI) was determined according to the methods of Reineke (1933) and Curtis (1982). The relative growth space index was determined according to the methods of Schröder and Gadow (1999). The research results showed that: (1) The Log(N) - Log(Dg) relationship of R. apiculata plantations from 10 to 25 years olds was a straight line. (2) The SDI of the R. apiculata  plantations was determined at class A = 25 years; in which Dg was 20cm and the slope b = 1.538. The SDI index of the R. apiculata plantations from classes A = 10 - 30 years can be predicted by the function SDI = 3177.86×exp (-14.6974×A-1.1441). (3) The relative density index (RD) of the R. apiculata plantations from level A = 10 - 30 years can be predicted by the function RD = 48.9322×exp (-6.36089×A-0.535219). (4) The relative growth space index (RS) of the R. apiculata plantations from level A = 10 - 30 years can be predicted by the function RS = 0.0758799×exp (4.70405×A-0.8861). The findings of this study offer valuable insights that serve as a scientific and practical foundation for establishing technical criteria for tending the R. apiculata plantations in the Ngoc Hien coastal area of Ca Mau province.