To the wonderful translation of Mr.. Gizbar I would just add the following:
The deceased and his father were Cohanim (plural of Cohen), members of the priestly tribe that traces back, son to father, to Aharon (Moses' brother), the first Cohen. The image at the top of the stone shows the priestly hands that bless the congregation.
The poem of praise is an acrostic poem, with the first letters of the first 8 lines spelling out the name Yosef Yaakov. I am not sure about the last lines, although they might spell out a version of "Cohen".
The reason that the year is not clear is because it is obscured by the leaves at the left side. Do you have another photo? If not: do you know his secular date of death? With this, it would be possible to determine the complete Hebrew date of death.
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Fredel Fruhman
Brooklyn, New York, USA