People who don't live around trees all the time don't realize how much heavy stuff they rain down when it storms, or the wind blows just a little. A forest is a very dangerous place in a windstorm, and not just to those who are incredibly unlucky, like this poor woman. Just to put it in perspective a bit, oak weighs almost a metric ton per cubic meter. A thick branch can be close to 100 lbs per foot. A ten-foot branch with a diameter of about nine inches split from an oak over my Dad's house years ago, and completely destroyed a screened-in porch.
If the wind blows hard you should not be in the woods, period. If you are in the woods and a storm strikes, you're in a bad spot, because to be safe from lightning you'd want to get away from the trees, whereas to be safe from falling debris I'd want to get right up next to the trunk of the largest one nearby.