two sample test with control group having all zeros

[treestatsnoob]

I am testing the density of seedlings in plots that were burned to those that were unburned for different species groups. For one of my species groups, there were 0 seedlings in the unburned plots (n=20), but there were seedlings of that group in the burned plots (n=20). I have unequal variance and non-normal distribution. I have tried several transformations to no avail. What test should I run?

thanks,

 

[hlsmith]

Can you provide a sample of your data, so we can see what density looks like, also - what is your sample size?

 

[treestatsnoob]

i have 20 plots in the burned area and 20 plots in the unburned area

 

[Karabiner]

I do not know whether a statistical test makes much sense here at all,
but I guess that the Mann-Whitney U-test can be used here.

With kind regards

Karabiner