Crescimento e cobertura do mangal Avicennia marina nos campos de reflorestamento de Icidua, cidade de Quelimane

Abstract

The present study on mangal growth and cover was developed with the main purpose of monitoring the various stages of growth and cover of Avicennia marina in the reforestation fields of Icidua, near the city of Quelimane. corresponding to thirteen (13) months in two phases, including the first phase that covered the months of February to September 2016 and the second phase that covered the months of May to September 2017. The parameters analyzed in this study were: growth, total number of surviving plants per block, plants with heights higher and lower than half a meter (50 <h cm <50). The number of surviving plants in each block was obtained by monthly counts in the blocks and calculated at the end of the monitoring the arithmetic mean. Plants that reached a height of more than 50 cm were also counted monthly and the arithmetic mean was found. For plants with a height of less than 50 cm, the total number was obtained by the difference between the total number of surviving plants per block and the plants with a height greater than 50 cm. In order to obtain the growth rate of the plants of the monitored area, 4 experimental blocks were selected where measurements of height of the plants and diameter of the base were made with the aid of tape measure and pachymeter with precision of 0.1 mm in some plants signaled and listed. The results obtained indicate the presence of approximately thirteen thousand and ninety - six plants (13096), where block 4 presents the highest vegetation cover followed by block 5 occupying a percentage equivalent to 57% and 13% respectively. The maximum plant height is 130 cm and the average growth rate is 9%. In total there are about one thousand seven hundred and one (1701) plants that have height equal or superior to 50 cm. The diameter of the plants ranged from 5 to 26 mm. Based on the study done, it is concluded that the Avicennia marina mangrove plants reforested in the Icidua reforestation field are growing at a rate equivalent to 9% per month.