RESEARCH ON TECHNIQUES TO IMPROVE BIOMASS AND QUALITY OF MANGROVES IN RESPONSE TO CLIMATE CHANGE IN CAN GIO COASTAL AREA, HO CHI MINH CITY

Abstract

The study was conducted in compartment of 1, 6B, 21, 24 and AHAP of the Can Gio Mangrove Forest Management Board, from September, 2022 to August, 2025, by setting up 4 completely randomized experiments, with three replications, namely (i) density adjustment experiment (N) according to formulas (N4- strong, N3- medium, N2- weak, N1- light and No- control); (ii) forest enrichment experiment with 3 formulas (LG1-creating a bed 3 m wide to plant a row of trees, LG2- creating a bed 6 m wide to plant 2 rows of trees, LG3- planting in small plots ); (iii) arranging 2 experimental formulas for planting trees in the upper layer (TT1- creating a bed 3 m wide to plant a row of trees in the upper layer, TT2- creating a bed 6 m wide to plant 2 rows of trees in the upper layer); (iv) planting trees in the lower layer including 2 formulas (TD1- creating a bed 3 m wide to plant a row of trees in the lower layer, TD2- creating a bed 6 m wide to plant 2 rows of trees in the lower layer and). The results showed that the changes in growth diameter, height, biomass and forest quality in the experimental treatments were: (1) strong, medium and light density adjustments (treatments N1, N2, N3) all met the criteria for growth in tree diameter, canopy diameter, biomass and tree quality in the forest stand; treatments N1 and N2 had the best growth, total biomass and forest quality and were recommended for technical measures to care for and enrich forest quality; (2) the trees that enriched the forest grew well, the fluctuations in density in the experimental treatments remained high at LG2 (1,870 trees/ha), LG1 with 1,760 trees/ha, LG3 with a density of 1,745 trees/ha,; treatment LG1 has improved total biomass and forest quality compared to before the experiment   and treatments LG2 and LG3, this treatment is selected; the species Sonneratia alba  has better survival rate and growth is proposed to be planted to enrich forest (3) treatments TT1 (in rows) and TT2 (in beds) have good survival rate, biomass and forest quality so they are selected; the species Lumnitzera racemosa has better survival rate and growth is proposed to be planted to enrich the upper layer forest and (4) treatments TD2 (in beds) have good survival rate, biomass and forest quality so they are selected; the species Bruguiera sexangula has better survival rate and growth is proposed to be planted to enrich the lower layer forest.