First of all, read this:
Lessons From the Hudson River School of Painting
and when you're done, try to articulate a single lesson the author has learned, or feels that you could learned specifically from these painters. Stuff about 'light it important' and 'leading lines!' doesn't count because those "lessons" can be "learned" from almost anywhere, and there's nothing specific about the Hudson River School there.
Let's examine this little piece and see what he's actually saying.
He begins with a little discussion of how he teaches and has this creativity/personal expression based approach. Then he states that a great way to cultivate creativity is "the study of painting". So far so good.
So, perhaps he's going to show us how to cultivate creativity by looking at these paintings?
Then he goes on to discuss the qualities of 19th century landscape painters (getting the century wrong along the way, but that's the sort of error anyone can make) talking about the sublime and so on. Harmony, the serene, the mysterious, are all referred to. Certainly these were the intentions of these painters, no argument there. He's quite right.
So, we have some things we could strive for, if we wish to make landscape photos with similar qualities. Fair enough.
A thumbnail history of the Hudson School follows, which as far as I know is perfectly correct. It hardly matters for our purposes, though. I assume it is all spot on.
Then we get to, apparently, the meat of the thing. He actually tells us what we can learn! Three things: Composition, Light, Symbolism.
Then the wheels begin to come off, as he steps through these things:
Composition. The Hudson River School used it. The composed pictures. Yup. Leading lines! Shapes!
Light. The Hudson River School used that too. Really well! Masterfully!
Symbolism. Here he actually deigns to cite a specific thing: Small people in big landscapes, a fully legit bit of symbolism. Well done. But then he's back to how the Hudson River School used symbols! Masterfully! To create emotion!
So, there's one actual, actionable, lesson here: put small people into big landscapes to create a sense of bigness of the landscape. The rest is filler.
Then he goes on to show us a bunch of his own pictures, which look nothing like Hudson River School pictures, and which draw no apparent lessons from that school.
So, what's he actually saying? Half the time (during the the Composition/Light/Symbolism) portion, he seems to be suggesting that we can draw actual lessons, in the sense of methods we can use, from these paintings. He does not bother to tell us what those methods might be, though.
The other half of the time he seems to suggest that we should just look at the paintings for inspiration. He gives us no specifics here, either, though, beyond "gosh, these guys were great at painting!"
It strikes me that the point of the essay is not to actually communicate anything.
It exists to wrap the author in the mantle of authority he perceives the painters to have. It is targeted at an audience that does not feel they need to learn anything from paintings, but do like to nod their heads wisely when some dope says "we can learn so much from painting." This audience will be too busy nodding to notice that there's no actual content in the essay.
It is an essay aimed at people who imagine they already know it all, in exactly the same way so much contemporary photography is aimed at photographers, who can then nod wisely at the powerful leading lines and so on.
And, let us not forget, the author runs workshops. You could give him some money and have him bleat at you about Light! Light! Light!