5 degrees or 15?

Some bonsai literature claims that tree roots don't grow when a tree is dormant. Trees go dormant when temperatures get below 15 degrees. Other bonsai literature claims tree roots grow until the temperature lowers to 5 degrees, and resumes at the same temperature in the spring.
Someone in the bonsai club suggested that it probably depends on the species. Therefore, this year I am keeping a list of which tree's roots are active at repotting time, and which are not.

On a related note, bonsai literature tends to assume that new root tips are sensitive to breakage, freezing, and chemical burn from fertilizers. But some other literature suggests that new roots, new root tips and roots in general are as hardy as they need to be. Hence cuttings, seedlings and newly repotted trees can all be fertilized normally.

Who Knows?

Potting/Nursery Soil Rant

Potting soil is not good for bonsai. A flower requires a good growing medium which will be thrown out in three months. Ta da, we have potting soil. It is a mix of sand and peat with a bit of fertilizer. Peat is dead moss. Roots find it easy to grow in this mixed medium, especially the freshly transplanted flowers. As moss is an organic compound and it has no cellulose structure it breaks apart over about 8 months. It breaks apart because of swelling and drying out, as well as through natural decay processes. The broken bits filter in between the sand and plug up the spaces. Water no longer flows through the soil watering the roots of the plant in it. Water pools on the top and seeps down the insides of the pot. What little water does make it inside the tight packed soil mass does not evaporate quickly and promotes rotting of the root. Of course rotting roots are bad, so potting soil is therefore bad too.
Nursery soil is about the same but the soil mixture includes a substantial portion of bark. Too much bark promotes too much moisture. As well, the high proportion of bark means a lot of organic material is breaking down at the same time. The bark is composed of cellulose, it has a harder structure which takes about 1 year to become compacted.
The solution to a plant in a compacted soil is to transplant the tree when the tree is healthy and vigorous. If it is not the right time for transplanting, the plant's soil should be fully immersed in water occasionally. Keep the plant's soil underwater until it stops bubbling.

Animals attack bonsai

There is some kind of animal. It comes into my yard at night and throws my small boxwood off the table to the ground. This has happened three times now.
The boxwood has not been potted from its old nursery soil to bonsai soil. What this means is that the roots of my boxwood are more or less fine because the nursery soil is compacted and holds the roots in place. If the plant were in bonsai soil, most of the soil would fall off the roots if the tree fell off the table. Then one would have the problem of replanting stress to deal with, in addition to the stress of being dropped. (breakage, moss loss, bending out of shape)
What am I going to do about it? I secured the plant to the pot more firmly with wire looped through the bottom holes and twisted tightly at the top, to aid the safekeeping of the roots. I hope the animal doesn't come back.