My Internet explorer is not compatable with photobucket or I would post some pictures.
You are well ahead of the game with the dowel jig I have one and it works great, nothing is perfect but it is great. You dont have to fell a tree but go ahead if you feel the need. You can get boards at local home improvement stores if thats all you have. They tend to be very limited on wood types and numbers of boards you can look thru. I have used poplar boards from these stores. I am lucky though and if you can find one in a reasonable distance go to a lumber store (Sears and Trustle in Northern CO is one I frequent) or Woodcrafters that has multiple types of hard and soft woods to look thru.
I am going to cause some wringing of hands and gashing of teeth here, but you dont have to have the perfect board to make arrows from. Is it the perfect thing to have straight tight grain with no run off, of course but not absolutly nessary. I would say that I use arrows with run off that an arrow company would not sell and have not as of yet had one break on me. As I go thru the process I contantly flex all shafts and any weak shafts tend to break on first flex. Caution is the key and tossing any you dont trust, flexing to test after each step in the process.
My method I look thru the lumber and find the board with the straighest grain I can, tight grain not as important to me. Some of the ash I have used you are lucky to get two growth rings on one 3/8 shaft. The heavy woods tend to have the higher gr weight of course but also heavy spine weight. At the lumber specialty stores they sell by the board foot. I have them cut the boards into 36 inch lenths, if not take board home and cross cut into 36 inch length. Then I rip into just under half by half inch squares. I look over any for small knots or other deformities and toss if needed. Then I chuck in electric drill use attachment for dowel maker and run thru. If weak right here the dowel jig will break off a really weak shaft. Just so you know getting the dowel jig to just the right setting can take some work but once there you are good to go, so expect a lot of wasted shafts till you get there. Use some pine or other cheap wood to get it setup. It will take some experimenting to get the correct feed rate to keep marring of shaft to minimum. Now you have a round shaft with square end. Flex shaft several times, spine shaft to see if it is in the ball park of spine weight needed. You want it some what heavier (in spine) than needed so you can sand down to spine you want and clean up marring at the same time. Flex as you sand check spine till you get the spine needed or close then finsish sand with fine paper. I turn my shafts to 3/8 then hand sand down to my needed spine weight without worring about shaft diameter. If its 3/8, 23/64, or 11/32 they all shoot the same spine is most important. With a little barrel sanding the tips and nocks if used fit just fine. If a shaft has gotten to this point with out splitting or breaking I dont worry about run off I use it. Now you are at the same spot as if you got from arrow source. Most important though you did it yourself and you are quality control. You will have some waste. I believe that probable only half the square stock I rip turns into a shaft I can use. Of the half that does not work for me to lite in spine usually they go to other projects or kids. The rest break or just are not clean enough to make shafts from.
Woods that have given me shafts in the 60-65lb spine range and around 350-500gr shaft. Ash, birch, doug fir, poplar, hard maple. These are the ones that have worked best for me there have been others with mixed results. Favorite two ash, poplar, least favorite doug fir. There is a lot I have learned just not enough time and this post has gone long. If you are interested I can post more later.