two sample test with control group having all zeros

#1
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

Less is more. Stay pure. Stay poor.
#2
Can you provide a sample of your data, so we can see what density looks like, also - what is your sample size?
 

Karabiner

TS Contributor
#4
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