I have tried both editing the family both ways. 

I tried editing the tree family in Revit in the way shown in the video posted to your site, but the scale parameter shown in the video is not present. 

I tried editing the tree family in Revit by unclicking the locked height parameter and adding in a new parameter, but that doesn't correctly scale the family. I tried exploding the tree and scaling it which did work, but then the tree didn't appear in 3D views. 

Please advise. 

Are you editing the family as shown in the video, or trying to adjust the type parameters from the Revit project?

I purchased the Amabilis Fir which comes with 6 scaled options of the tree. While you have a video on your website that says trees can be scaled using the scale parameter, no such option is given. I have trees that I need to model that are higher than 40m, the height of the tallest tree in my package. Scaling up doesn't seem to be feasible. Can you tell me how to scale the tree I bought to be higher than 40m? 

The height, when unlocked doesn't scale the tree either. 

Please advise. 

Scaling on the Coconut Palm Tree does not work at all.

Please follow the instructions as on this video.

https://www.youtube.com/watch?v=NQv2jxnfiGw