Daniel:

I concur with Guillaume with some additional comments:

2) To be cost-effective, the 12" or 14" length is best in most circumstances. Buy multiple (2-3). Then buy 1 long core to be used on your biggest trees. We used a 24" one to core oak here in Indiana. Use it sparingly; they cost 6x-10x the cost of the short ones.

4) Get Jim Speer's dendrochronology book; he has a great list of items needed. You will need a sharpening kit, bee's wax (lubrication), WD-40 and a rope (used to extract a stuck bit). You will need golf tees for extracting stuck cores (NEVER use the metal extractor to push out the core from the thread site).

5) 3-thread - ALWAYS. If you are doing a lot of softwood, you may be able to get a converter and use a power drill (24V Dewalt).

Lastly a hint: Use a 12" or 14" handle on any borer longer than 20". You can bend the handles on those long borers, then you can't get the shaft back inside (or worse yet, it gets stuck on the inside).

Mike

Mike had a good answer here. I would add that I used McDonald's straws for my cores. They are wider than the ones you can buy at the store. Also, a lighter works great to melt the end of the straws shut in the field. Lastly, wrap some electrical tape around the end of the borer handle so that you can use it when you have long cores that won't fit in a single straw. You will also need mineral oil for sharpening and a rifle cleaning kit and cleaning patches to clean the borer using wd40 sprayed on the patches. Clean it every night after you're done in the field so the borer doesn't gum up. I think a 22 caliber will work, but I can't remember. The best thing to do is to bring the borer in to the sporting goods store and make sure it fits.

Be careful about using McDonald's or other plastic straws. They are fine for collection, but not for long-term storage (unless you are storing in the freezer). Plastic doesn't "breathe", so the cores can get moldy. I actually buy paper straws because I can have the cores dry inside the straw. I also find them easier to splice together than plastic for those really long cores. There used to be only a couple sources for paper straws, but more online stores are carrying them now. Like H. Poulos, make sure you buy the larger diameter versions.

I typically use a hole punch to put a couple of holes in the straws to aerate so that may work too.

Thanks guys! My material preparations are going well, and I am keeping an eye on here to consider your new comments.

Make sue you have a good knife or leatherman to cut the straws down to the right size for your cores....and to open beer bottles after a long day in the field :)

Presumably the sampling in this case is for live trees. Dry, cut timbers used in archaeological or historical contexts can be best sampled by hollow, toothed drills of various lengths and diameters (I prefer 5/8" dia.), common to SW U.S. work.

I found a supplier of paper straws and bought a lifetime supply some years ago - they can be difficult to find.  I recommend them over plastic straws.