Went on a hike in Oregon and saw this beautiful example of hugelkultur in nature

I wonder how old it is. 10 years?

Nice! I love seeing all the plants growing out of nurse logs up in the Olympic National Park in Washington. I was reading a book about the Andrews Experimental Forest and they have been doing research now for decades on the decomposition of fallen old growth trees and all the life that lives in these fallen trees. There is estimated to be more living mass in these "dead" trees than in the standing living trees! Also, it is estimated that it will take 100-200 years for these old growth trees to fully decompose once they fall! Really amazing stuff that we are just barely touching on with our techniques.

Nature is so inspiring!
"A nurse log is a fallen tree which, as it decays, provides ecological facilitation to seedlings. Broader definitions include providing shade or support to other plants. Some of the advantages a nurse log offers to a seedling are: water, moss thickness, leaf litter, mycorrhizae, disease protection, nutrients, and sunlight. Recent research into soil pathogens suggests that in some forest communities, pathogens hostile to a particular tree species appear to gather in the vicinity of that species, and to a degree inhibit seedling growth. Nurse logs may therefore provide some measure of protection from these pathogens, thus promoting greater seedling survivorship."
- Wikipedia article about nurse logs.