AI know there have been many talks about the tree stump cake, I haven't found any forum posts where anyone has successfully made the cake. The cake I would LOVE to make is made by Kaysie Lackey and I found the pic on Pinterest. Anyone know if I should use buttercream, modeling chocolate or fondant?! Please please help! My brain won't let me stop thinking about this cake : )

AUse whichever you are most comfortable using. I know that's not the answer you were looking for but it really is just personal preference. Of course there are times when a certain medium might be more appropriate to use than another to achieve a specific affect but I think that still depends on skill level and personal preference.

If you're asking what medium was used on that particular cake, we'd need to see a picture.

Ahttp://www.cakefu.com/feature-friday-kaysie-lackey/

This is the link to the cake, I didn't know if I can post pictures of other people's cakes. Thank you so much for the reply : )

If I were making that cake, I would cover it in buttercream and then wrap the sides in fondant. That way you could roll out the fondant, form the knots, bumps, etc. and paint it while it's flat, then attach it to the cake.
 

Acakecentral.com/t/755283/apple-tree-trunk-wedding-cake-how-do-i-make-this-cake

I just saw that Kaysie Lackey has a on-line video on how to make this cake on Cakemasters.com.  I think it is $35.00.  Hope this helps.