We used a natural pine log as the central support in my house. I hand sanded it with 120 grit sandpaper, then sealed it using Miniwax pre-stain wood conditioner. After that I stained it using Miniwax's golden oak penetrating stain...but the finished product looked darker than I wanted (See image 1). In a misguided attempt to fix it, I hand sanded the log again, but that caused white lines to appear on the high spots (See image 2). This looks pretty crummy. How can I fix these lines and bring this project back on track? Since this is in the center of our living room it's fairly important that the finished product look good. I appreciate any and all responses! Help!

Here's an answer from Gene Wengert, the Wood Dr.:

When a pine tree is growing, in the spring time it creates wood cells, mostly vertical in orientation, that are fairly wide open. As summer comes, the tree makes dense, non-open cells.  So, when you try to stain this wood, penetration in the earlywood cells within an annual growth ring is good and can go 1/4" deep.  However, the summerwood cells absorb very little stain, so light sanding will expose the original color (light color), unstained summerwood cells and the dark colored, stained spring wood cells.  The transition from spring wood to summer wood is often quite abrupt.  So, the white lines you see are unstained summerwood cells.

I am not the best finishing expert on the best finish for this material, but it would seem that using a stain within a film forming top coat (like polyurethane) should be considered rather than a penetrating stain and clear top coat.  It would seem obvious that you do want the grain to show no matter what finish you use.