> That seems to be jumping to an extreme end, that someone owns an empty plot of land that has been cleared and destroyed to bare, dead dirt. My concern is that the same incentive pushing one to sell a pile of dirt would exist for someone owning an undeveloped, natural plot of land. My earlier caveat still exists, maybe this isn't a concern in dense areas though it would add some blockers for anyone interested in turning developed land back into a park.

If you're not doing anything with land in an in-demand area then it creates an incentive to sell it, yes - that's pretty much the point. Realistically, undeveloped lots in in-demand areas (i.e. cities) are not nice natural landscapes - they're dirt yards at best. It takes a lot of work to maintain a park, and frankly putting a tax on land is more likely to return some of those unused lots to the city who could then open a public parks there, than discourage someone who was maintaining a park privately.

Even in the country, land that's completely untended is rarely pleasant, although in places where land isn't worth much, a tax like this won't make much difference either way.

> One concern I have is the expectation that all land should be optimized for productivity. That goes against my own view on land, I don't think we humans have some innate right yo extract all available value. I also don't like that this likely goes against concerns of environmental impact.

The idea that someone owns land like chattel and can do whatever they want with it is surely worse from that point of view. If you're taxed on the value of your land, you're incentivised to use as little as possible, and leave the rest for the public or nature - e.g. if you can build a factory in half as much space, you've halved your tax bill.

> The market only decides on my land's value when I sell it. Until then, is the land valued at what I paid for it?

No, there would need to be an assessment process, although perhaps backed by a market mechanism (i.e. if you think the assessment is too high you can ask the government to buy you out at that amount, or some such).

> Taxing to create incentives to build as high-value improvements as possible would inevitably lead to a drastic increase in a locality's energy requirements.

It doesn't create a new incentive to build more unless the more you're building is valuable. You can densify by building more in the same space yes, but you can also densify by building the same in less space, and that's what saves you money so presumably that's what people will do (after all, if building more was profitable, wouldn't people already be building more)? For the same amount of economic activity, you'll require the same amount of energy, just in a smaller space, which again is likely to be more efficient and better for the environment (the same number of factories in half the space means fewer cables, less transmission losses etc.).

Now of course if you make business more efficient then maybe you end up with more business, but isn't that a good thing? Again it only makes sense to build more if there's demand for it - otherwise you're better off staying small and cutting your expenses. Land value tax might even help encourage people to not expand prematurely - if doubling the size of your warehouse means paying more tax, maybe you'll put it off a few years until you're actually going to use that space.