How can I calculate correlations between fungi presence and forest health in two different forest sites? I am working on an undergraduate thesis and I have extremely little knowledge on statistics so my analysis is going to have to be quite basic. In two different forest ecosystems (plantation and mature) I surveyed 175 quadrat samples over time for macro-fungi presence. My data distribution is not normal. I have compared diversity using Kruskal-wallace and am looking to establish if there is a correlation between forest health (assuming my mature site is healthier) and fungal presence (abundance??). Of 175 samples, my mature site had 94 individuals present, while the plantation site had 14. I am wondering what test of correlation is best for this data, and I am using excel. I could potentially use R but I would prefer not to as I do not know how. 
Thank you and my apologies for the lack of knowledge on stats.
 A: It would help to know the kind of relationship you can see in the data, or to see a plot of the data. If you are testing for a linear relationship, use Pearson's correlation coefficient, which will indicate to you the strength of the relationship between the variables. For cases where the data is non-linear, there are other options for hypothesis testing however these will be very situational, hence my interest in seeing the data. Some examples of these are Spearman's rank correlation coefficient or Kendall's rank correlation coefficient (Kendall's Tau).
A: As some very basic analysis, you could use a Mann-Whitney U test to test for a difference in fungal abundance (presumably counts of the macro-fungi in each quadrat?) between your two forests. You could probably use something similar to compare species richness between the two forests as well. I'm assuming you don't have any actual measurements of forest health at the level of quadrat?
I don't think it is easy to do Mann-Whitney tests in Excel, as it doesn't store the relevant p-value lookups. But you can find online calculators that make it fairly easy. e.g. https://planetcalc.com/7858/
Be aware that your results may well have nothing to do with forest health. Mature forests are well known to have a greater diversity of fungi compared to young plantations due to normal succession, irrespective of the health of the forest. A natural forest may also have a more diverse pool of fungi in surrounding areas to colonise it, compared to a man-made plantation as well.
