I think these two articles will help answer the first two questions, and help me from doing a lot of explaining as far as trunks go :) Brent Walston's site (first link also has other articles that will help you.

http://www.evergreengardenworks.com/trunks.htm
http://bonsaijournal.com/beginners-trunk-chop-101.php

I would allow the roots to stay the way they are and keep as large a root mass as possible (in a larger pot) while the tree is in training. The larger the root system the more vigorously the tree will grow and it will develop quicker. At this point the only root work that should be done is the removal of any 'tap roots' (roots growing directly downward) and any radial roots that are growing at a bad angle too large and out of proportion with the rest should be trimmed back.

One of the most prevalent problem in the west is people are over anxious to get an instant bonsai and or put their trees in a Bonsai pot right away. I would save a Bonsai pot for a tree that has reached the refinement stage(no longer in the training stage) as once the trees roots are reduced and it is planted in a more confined Bonsai pot the tree will slow down in growth and development drastically. As for the second question, yes you should always use some training wire to secure the tree in the pot. This is to keep from have the tree fall out of the pot in the instance it will be knocked over as well as other reasons.

As for soil while mixtures are tailored in accordance to the local weather conditions it is always best to use a course free draining soil that stays moist no longer than 2-3 days tops. Boon Manakitivipart's Mixture works just about anywhere though and is a optimal choice in my opinion and is comprised of equal parts Akadama,Pumic, and lava rock. That being said it isn't the cheapest and Akadama might be hard for you to find (cheaply). You will have to play around to see what works best for you but for a begginer Turface MVP is a good additive to use (and can be found at just about any sports store or farm store).

All in all if you are a beginner nothing is better than to find and join Your local Bonsai club where seasoned artists will be able to give you valuable information as to special needs in your geographical location. Your local libary is also a good source to read up on Bonsai books at no expense.

Hope this helps and good luck on embarking on your new and wondrous hobby.

-Mike

I live in So Cal. Due to high winds, the tree keeps getting knocked down. The tree was pulled from the ground and seems as they reduced the root ball to fit a 15 g pot. Some of the roots look like they been cut down already. The tree does not look like its doing so good. Would it damage the tree even more if i were to do the trunk chop and reduce the roots now?
{{gwi:22633}}

I'm not sure if your tree (at the moment) is not doing so well because of the weather. Around here, OC area, the plum trees normally lose their leaves, the ice cold nights are not helping much though.

The Wiz is right....plums are going/have gone dormant in these parts.

To your question, Yes, further root-pruning and/or disturbance will likely impact
the vitality of your tree. Wait, let it regain energy.

In the meantime, describe where you plan to chop the trunk?

Josh

Oh, I was going to ask, is there any specific area you have to avoid when doing a trunk chop?

I've been air-layering a branch on one of my orange trees (coming along nicely) that had become damaged from so much fruit being on it and thought it might be a nice outdoor plant.

Greenman, i was hoping to get some advice on where to chop it. I was thinking about halfway from the root flare and the first lower branch. I was going to root prune it and chop it all together and let it sit for about a year or plant it on the ground to increase the speed of the new growth and pick my main and re chop.

How tall would you like the tree to be when finished? Like I mentioned before the chop should be done at 1/3 the height as you wish the final tree to be (if you envision the finished tree as being thirty inches tall then chop the trunk ten inches above the soil).

I would recommend allowing the tree to strengthen its self for at least a year before doing a drastic chop. I will also help if it is allowed to grow freely in the ground.

Ah, so there really is no limit to how low you can chop? It's just the more dramatic a chop, the longer it will take to recover?