Income received before delivery lowers the fair forward price.
Income lowers carry
Income paid to the asset holder reduces the forward price because the forward buyer does not receive that income before delivery.
F0=S0(1+r)T−income future value
Dividend example
With income of $3.00 at maturity, the forward price is $105.00 minus $3.00, or $102.00.
F0=$105.00−$3.00=$102.00
Storage goes the other way
Storage costs work the other way. They add to carry because the holder pays them while carrying the asset.
income reduces carry; storage costs add carry