I have read several of the posts on the Flemish Goedendag as well as seeing an excellent article on the subject by De Liebart, http://www.liebaart.org/goeden_e.htm. After seeing these things, I would like to try to make one, but I have a few questions that I hope that some of the readers of this forum can help me with. First, what kind of wood would be used? Would the wood have been trimmed from a sappling or cut from quartered boards? Also, what is the diameter of the staff at the head and the base? Lastly, does anyone have any good spike and collar dimensions? Thanks for any help.

For a reconstruction piece not intended to actually be subjected to abusive use, you could chose just about any medium weight/hardness hard wood.

A lot of sappling ash trees and "quartered larger tree staves" were cut at this period. Ideally you would seek out a young tree with about a 2" to 3" diameter trunk that has grown tall, straight, and relatively free of side limbs and knots within a dense forest. 6 months after cutting it is still somewhat flexible and slightly "green", which is a good thing if you finish it so that it retains some moisture and flexibility. You don't really want to cut through lots of the growth rings (drastic tapers in thickness are not good) as the concentric growth rings running continuously along the length are something of a natural composite structure (critical to bowyers, although this is not a preferred specie for a bow.) Ash staves were good for staffs (quarter, full, or half staffs, lances, etc.) The ash specie is a little special. It resists excessive splintering on impact, which is why it is still often used for canoe paddles and such. From a safety perspective, it is a wise choice for a pole arm or lance as well.

If you can't find, or don't want to go to the trouble of seeking such an ash tree, you could just buy a loose hickory axe or maul handle at a hardware store and reshape it with a belt sander and such. These are similarly durable, competitive with the highest strength to weight properties you will find in a natural wood, and have good resistance to splintering. In terms of appearance, most non-woodworkers won't notice much difference.

are straight branches as good as trunks? I have a tree that has to go down to make way, it does not have a nice trunk, but some of the branches have a nice, long straight part to it

Even pine was used for some of these. They were mass-produced peasant weapons, after all. But, yeah, ash is always the better choice for polearms.

What would were the common woods available in the Flanders at the time? Obviously, ash was widely available. What about white oak, maple, beech, birch, etc? Also, any ideas as far as dimensions are concerned?

I wish I knew what was there at the time. Today you can still find spruce, ash, oak, beech (another great one for high impact tools.) You might look at remaining forests around Brabant.
http://www.expatica.com/actual/article.asp?su...ry_id=5728

IIRC, either Waldman or Snook mentions that ash was first choice, followed by oak. Given that hierarchy, one would assume that other common hardwoods would follow, with pine bringing up the rear.

pine is now the tree that has a large majority, but this is a very recent situation. I think birch and poplar would be common as well, but not so useful. Looking at current forests would not be the best referral

So goodendag means good day? I think finals are warping my brain but kept imagining some soldier running around with a crazy smilea nd smacking knights and saying "and a good day to you sir". It made me laugh but it could be the finals making my sanity slip too.