Mapping and monitoring top-dying disease of the Heritiera fomes tree species in the Bangladesh Sundarbans

H. fomes in the Sundarbans has been affected by a disease syndrome called top-dying. Examination

of such trees reveals that the bark dies first and is followed by the death of sapwood. Occasionally

rot of both sapwood and heartwood may occur simultaneously (Rahman, 1996). Top dying of H.

fomes was first observed in the Sundarbans at the beginning of the 20th century. However, there

is evidence that the disease syndrome was widespread or causing major losses prior to the early

1970s (Boa, 1988). According to preliminary estimates of the prevalence of the top-dying of H.

fomes, over 17% of the stems in all forest types where H. fomes is a major species are moderately

or severely impacted (Chaffey et al., 1985). Chowdhury (1988) estimated mean annual timber loss,

due to the disease to be 1.44 million cu. ft. of timber which worth Taka 2000.00 million. As H.

fomes exhibits ecological and height dominance in the Sundarbans, the loss of the species is likely

to have a wider impact on the ecosystem as well as direct financial loss (Karim, 1988). Therefore,

continuous monitoring of the top dying of H. fomes in the Sundarbans is important to safeguard

this species.

Objectives

The objective of the study is to map the distribution of the top-dying affected H. fomes species

through remote sensing and develop a google earth engine-based app to monitor top-dying in the

Bangladesh Sundarbans.

• Supervision