You're very welcome Phil. You give a lot of very useful information to others here on GE so you deserve some back in return.
One thing: There's really no need to apologise for asking questions - I've asked heaps and got very good advice each time.
With some of the Cedrus family - Cedrus Atlantic etc, the needles naturally reduce as the tree gets older but not so much with pines. The shortened needles are the result of pinching the tips out. The needles are actually made up of a number of individual segments. Never cut the needles to length with scissors or pruners, they will go brown at the ends and don't look very good. Always pinch them out with your fingers. When you pinch them out, you are actually separating them at the segment join. Scroll down towards the bottom of this link. I put a bit there with photos about how to pinch out a juniper but the same applies to pines:
http://gardenexpress.com.au/forum/viewtopic.php?f=21&t=5516Most pines grow 'candles' which are the new growth and you'll see them in the clumps of needles. Let them grow a bit, but before they put out new needles, pinch then back by 1/3 to 1/2 their length. This will induce more dense foliage pads.
With regards to re-potting. If you were working with a fig and most other species, you can hose every trace of old soil mix without any problems. With any of the pine family, and Junipers - and possibly for Cupressus, Cedrus, Thuga etc, NEVER, EVER completely bare root them. They have a symbiotic relationship with a fungus called Michorriza. The fungus converts nitrogen into a form that pines etc can take up. Without it, the tree is almost certain to die. In return the tree supplies nutrients to the fungus. When you take it out of the pot, comb the roots out, but leave some soil on them, especially up near the trunk (the fungus will spread from there).
On re-potting it's also a good idea to keep some of the old soil mix from close to the roots and include it in with the new mix as you pot the tree up. This will also ensure the Michorriza is present for the tree to use. You don't need much - one or two tablespoons will be plenty.
If there is still plenty of space in the pot, you may not need to prune the roots, but if the pot is full - especially if the roots are starting to wind round the inside of the pot, yes prune them back a bit. Being a pine, they aren't as vigorous in growing roots as say members of the fig family (my figs get re-potted at least twice a year because of the huge amount of roots they put out).
All pines are best grown in full sun, just make sure it doesn't dry out. Because of the limitations of keeping it in a Bonsai pot, you may need to give it some protection from frost. The trunk and branches etc will survive freezing conditions without any problems, but if the roots get frozen, the tree will most likely not survive. I know in very cold winter climates (UK etc), they are put into boxes filled with straw that covers the pot and soil mix but not the tree as a whole. A shadehouse in our climate would be adequate during the coldest winter months - it just needs something to keep the frost off the roots and pot.
Something that some people new to Bonsai don't realize (not because they're dumb or anything) is that even in winter, Bonsai need to be watered. Because of the limited amount of mix in the pots, even in the winter they can dry out fairly quickly. All plants, whether dormant or not still need water to survive. They have the idea that because a tree is dormant - especially deciduous ones, that they don't need water. A tree or any plant in the ground for that matter still takes up water in the winter - albeit a lot less and a lot slower than during the warmer months. For that reason, overwatering during winter can also cause problems. As long as the soil mix is just damp they don't need watering - and a good rule of thumb (as with anything in a pot, is to poke your finger into the soil. If your finger comes out damp, it doesn't need watering.
Hope that answers some of your questions Phil. If you have any more, please don't hesitate to ask
