What resistor do I need?
You should calculate the resistance based on the minimum forward voltage:

$$\frac{36\ {\rm V}-30\ {\rm V}}{R}=3\ {\rm A}$$

So really you want about 2 ohms, not 1 ohm.

And the power consumed by the resistor will be \$I^2R = 3^2\times 2\$, or 18 W. So 10 W is not adequate. You might use, for example, three 6.2 ohm 10 W resistors in parallel here.

As another answer says, to deal with the Vf variation without changing the LED brightness, a constant current source is better than a resistive current limiter.