Regarding wood
hugelkultur aside (google it, if you are unfamiliar. fascinating...almost a cult...maybe it is?)--
Rotting really limits the functionality of using wood as a structural piece in the rock garden for sure!! Also ants, wasps, and all manner of 'varmint'!
Because the pine tree roots in the pic are the literally the roots that I removed from underground, (previous post/another thread) they are holding up fairly well for a few years now...but they wont last forever...have always intended to change that up since the day it went in anyway.
As admitted, I have a blueberry and strawberry mound, currently supported in mound-shape with logs, and mulched w/ wood chips. In this case the eventual breakdown is okay. Furthermore, the soil mix there is very compost rich because blubes and strawbs like it but also decomposing wood into compost, i.e. eventually giving nitrogen back, actually consumes a great deal of nitrogen in the process and can rob it from the hungry plants.
not to be all didactic...but
wood pieces, stumps, logs and the like--in the garden, on and near the surface-- the primary mechanism of breakdown is fungal decay given sufficient moisture, even 'dry rot' is caused by a fungus, unlike 'regular' composting, which is done by bacteria. For the adapted woodland plants this is not a problem at all and in some cases there are beneficial arrangements between fungi and plants; whereas for the non-adapted plants (because they live above timberline on the side of a cliff?) fungi can present serious problems. The issue with the non-woodland daphnes is characterized. I suspect that it can also be a problem for some other 'strictly' alpine plants as well, but I don't know.
