Hugel Swales? With trees? Maybe worth a try.

There are so many good things about hugel mounds with respect to water retention and building fertility that I would lie to work them into my orchard (moving towards food forest) design.  Yes I have heard Paul's rant about hugel swales. I have noted that hugel mounds tend to subside over time.  

I have also seen wide swales alternating with trees, to provide a mowable swath for annual crops, in a slope that's not too great.  Was it Ben Falk or Mark Shepherd who was doing this? I saw it in a permaculture basics video series shot in the Northeast. 

I'm designing an orchard/ food forest near Eugene Oregon. Rainfall is 47 inches a year but mostly in the winter. So it makes sense to try to trap enough rainfall to keep the ground moist all year. So I have taken to heart to slow, spread, sink, etc as all good permies will do. After steeping myself in the writings and rantings of many different permaculture luminaries I plan to accomplish this in the following manner: 

On the southwest facing hillside I have in mind, the slope descends about 1 in 10.  With a 3 foot contour interval, the width is more or less 30 feet between contours. I would like to remove topsoil and shape the hillside into flat terraces with a berm on the outer edge two feet high on the uphill side, flat for 3 feet, and going down 5 feet on the downhill side at about 45 degrees.  After the topsoil is replaced, the slopes are to be sowed with clover and other good ground cover, and planted with various berries, filberts, and annual guild plants.  This leaves about 20 feet for a mowable fertility crop or pastured chickens or other adventures. I have enough slope for about 5 or 6 terraces 50 feet long. 

On the top of the berm I want to plant fruit trees of various kinds. Because I don't want these trees riding the slow avalanche as a hugel mound slowly collapses on itself, I am thinking of cladding the slopes of the berm (made from subsoil) with another 6-10 inches of logs and broken up ramial branches my predecessor has left lying around, then placing the topsoil on top of that, seeding with green mulch, and planting bare root fruit trees into the center of the berm and shrubs etc on the long slope. See the sketch.  

I am ignoring recommendations about hugel mounds going across contours, not mixing hugels with swales, and I don't know how many other no doubt well considered points of general advice given by people smarter than me.  My reasons are (1) frost and cold air flow is not a huge problem in Eugene (2) water must be controlled in both wet and dry seasons (3) I want to make use of all the red alder and douglas fir logs already cut and stacked hither and thither on the ground, some no doubt beginning to rot, along with some gnarly brush piles, and  (4) I want to play free-range bacci ball, graze chickens, and grow annual crops on the mostly flat terraces between the trees. 

So what problems do you see in this approach?  I'm one of those guys who has read a lot but have never taken on a project like this, so I'm bound to have some blind spots. Advice appreciated.