Asking for help regarding Random errors

Given that my model entails Ui which follows Normal (0, u^2), I ran SAS to estimate the random error (u^2)

but, to make it lie within boundary of variance (>=0), I used logsig_u term which expressed as log(u).

Now, I have the estimate and standard errors of log(u) but, the problem is I don’t know how to get the estimate of random error (u^2)
Parameter Estimate Standard Error
Log(u) -4.2593 14.0167

Is there any advice or help regarding my problem? Any help would be appreciated