Searching for lost tutorial

Hello, I was working through layer mask tutorials this week and I found one that features placing a tree over the background image of a lake, and then using layer mask to refine the selection of the comlex image of a tree. I was so impressed with the detail of the selection around the branches, twigs and leaves - allowing the lower layer to show through seamlessly. I searched for that tutorial today and couldn't find it using layer mask as a search term. If anyone can direct me to that tutorial by hyperlink or name, please let me know. Thank you!