It's fair to say that Donald Trump is not entirely happy.

Having rediscovered his Scottish roots, dormant for such a very long time, he now emerges as a defender of our natural heritage. In particular, our golf-related, leisure-oriented, prime-residential natural heritage. It stands, as the appalled Mr Trump has realised, in danger of desecration.

How did it descend to this parlous condition? Like a man from whose eyes the scales have just fallen, Mr Trump sees clearly now. Perfidious Alex Salmond, that false friend, has done the dirty with his clean energy.

You might have read the letter. If not, the precis is this: Mr Trump doesn't like wind turbines. In particular, he detests offshore turbines liable to be visible from his housing-with-golf development at Balmedie, north of Aberdeen.

Having endured the slur that fairways and residential developments might not necessarily enhance a site of special scientific interest, Mr Trump has identified the real environmental threat. It's wind-blown Mr Salmond and his turbine obsession.

Understanding, you might think, has been slow to dawn. First, the idea of a windfarm off the Aberdeenshire coast has been under discussion for at least half a dozen years. Mr Trump knew this: hence his complaint last year of promises broken. He said he was told that any such development would lie below a golfer's horizon. He therefore felt betrayed.

Secondly, it is not exactly news that the First Minister is keen on renewable energy. Mr Trump's people – people like Mr Trump always have "people" – should have made the boss aware of that, if nothing else. Some of us thought from the start that the First Minister was going too far out of his way to make a tycoon, this tycoon in particular, feel welcome. But if anything trumps Mr Trump in Mr Salmond's book it's renewables. That's common knowledge.

The timing of Mr Trump's letter might have something to do with the fact that the application for consent for 11 turbines, submitted last August by the Swedish firm Vattenfall and the Aberdeen Renewable Energy Group, has yet to be decided. The tycoon has found the Scottish Government helpful before – Mr Salmond was "an amazing man", not so long ago – and perhaps believes it can be cajoled again.

Thus: turbines are rubbish. They rust, fall to bits and have to be replaced or renewed "every five years". Mr Salmond – Unionists can take heart – will be long gone by then, "but the people of Scotland will suffer forever! With the reckless installation of these monsters, you will single-handedly have done more damage to Scotland than virtually any event in Scottish history!"

That puts Flodden, Culloden, the Clearances, mass emigration and deindustrialisation in their proper context, then.

Mr Salmond, having rashly suggested that Mr Trump would be "on board" with renewables after contemplating the benefits, is put straight. The First Minister is "hell-bent on destroying Scotland's coastline and therefore Scotland itself". The Donald will not go along with "this insanity". He is taking his stand "to save Scotland" and the honour of his Stornoway-born mother.

It is, in a certain sense, a terrific letter. That sense would be: you couldn't make it up. Mr Salmond should take comfort, though, from the fact that he is in august company. Enraged letters are something of a Trump hobby.

Just last November, troubled by America's relations with the Chinese, he wrote to the White House, telling Barack Obama, "It's time to wake up and realise that China is committing economic terrorism against the United States. You are single-handedly allowing numerous countries to destroy our great nation and everything that we stand for."

Previously, Mr Trump had been vociferous among "birthers", the group of level-headed right-wingers forever demanding proof that the president is American-born and eligible for office. Mr Obama called him "a carnival barker". Americans do not use the word "barking" as we might.

Last week, having ceased to suggest that he might be a presidential candidate, the tycoon endorsed the Republican Mitt Romney. The anointment duly took place in Las Vegas – where else? – with Mr Trump putting a philosophical spin on his decision. "Mitt is tough, he's smart, he's sharp and he's not going to allow bad things to continue to happen to this country we all love," he said. Mr Trump had previously dismissed Mr Romney as "a small business guy".

The Donald, in contrast, is a big business sort. That's no lie: Forbes magazine, house journal of the very rich, has been tracking his wealth since 1982. Last year it assessed the Trump fortune at $2.7 billion. The magazine also asked a couple of questions, however. As follows: "How can a man who has been bankrupt so many times remain a multi-billionaire? How is he worth more now, post-bankruptcies?"

Forbes was careful to point out, as are we, that while Mr Trump has filed for corporate bankruptcy on no fewer than four occasions – 1991, 1992, 2004 and 2009 – he has never filed for personal bankruptcy. He did lose out in 1991, at one point running up $900 million in personal debt after the construction of his Trump Taj Mahal casino hotel in Atlantic City hit problems, but he has been risk-averse since. As Forbes explained: "He stopped guaranteeing debt with his own wealth."

Mr Trump explained his strategy in an interview with the magazine. "Basically," he said, "I've used the laws of the country to my advantage and to other people's advantage ... just as many, many others on top of the business world have." It's the American way.

You can make your own judgment. You might pause to ask, though, why the First Minister was quite so enthusiastic about an inward investor with such a chequered history. When it comes to politicians, Mr Trump is not exactly consistent, but he has never wasted much time on social democrats. You might also wonder why, in the face of all the controversy over the Menie Estate, not to mention the scientific evidence, Mr Salmond was so keen on an individual described as "a carnival barker" by the President of the United States.

Mr Trump's letter suggests that someone's judgment was awry. It suggests we shouldn't be so susceptible – let's put it that way – to anyone who turns up talking big numbers. Our golf course crisis is not yet acute. There is an important debate to be had, ironically, about the actual value of wind turbines. The pity for sceptics is that they now have Mr Trump on their side.

In Washington DC, coincidentally, he has just caused some unease by winning the right to develop the Old Post Office Pavilion, a "Federal landmark building" with a historic 315-foot tower containing the Bells of Congress. The edifice was losing $6m a year and Mr Trump's plan for another "luxury hotel" was preferred to a bid from the Waldorf Astoria. Petula Dvorak, a columnist with the Washington Post, suggested that locals should relax. Who said Americans don't do irony?

Mr Trump, she wrote on Thursday, has "got the persistence of a lobbyist, the family money of a past president or two, the shamelessness of a scandal-plagued senator, the marital track record of at least one former House speaker ... and the self-promotional drive that draws so many of America's student council presidents to the nation's capital".

You can't say fairer than that. Clearly, Scotland should dispense with churlishness and allow itself to be saved forthwith. You can never have too much inward investment.