Poplar is as strong and light as cedar but it will tend to go out of straight more often. It is also easy to hand straighten.
Conifer woods make good arrows if you can get straight grain and natural dried wood. I have seen that kiln dried wood will tend to warp a LOT worse than natural dried.
Of all the conifers I prefer Lodgepole Pine (also called Chundo)The wood is lighter in weight for the same grain and spine as other woods. I like the light arrow for speed.
I know a lot of guys like very heavy wood and heavy points to get mass for penetration. We can argue physics all day long and most will not change their point of view anyway. I go back more than 50 years with Port Orford Cedar as THE premium arrow wood - but as the supply and quality diminishes and the price goes up - a lot of folk are going to alternative woods.
Much as I prefer things made and grown in the good old USA - the newest strain of cultured Bamboo for arrows shafts from China is amazing.
If you get the shafts from the best supplier, the shafts are very true, the nodes are clean and the nock end is cut at a node making cutting in a self nock very strong and far less likely to split. They are very tough.
A whole lot depends on the source of wood in your area. Some shoots like Rosewood, Dogwood, Ocean Spray and others make fine arrows if cut in the fall and dried natural. A good book or two and you can be on your way. Making a good shaving and straightening jig will be worth your time and I regret not having bought my Veritas dowel making tool many years sooner.