Then, when I spoke with Shane Jones, he told us it was 100 million minus what's already being planted.
And now there are questions around whether the government is backing away from a promise.
The Prime Minister has weighed in, claiming there is no back down. They'd promised this all along, it was a joint public private sort of thing.
This is part of an increasing number of explanations as to what we might, or might not have understood, or indeed misunderstood in the campaign: the 10,000 houses a year that won't start this year; the Pike River entry that won't be straight away because it isn't safe.
Now don't get me wrong, no-one loves a tree more than me, and if we plant a billion of them? Brilliant. It's not like we don't have room. It's not like they're not useful in terms of wood and the down stream products. It's not like they don't help the environment.
But when these promises are made, very few if any of us actually stop to work through the reality of what is being said.
One billion over 10 years is 100 million a year. Some of course would argue it's 1000 million, but let's not go there.
So 100 million a year, that is 8.3 million trees a month, or 274,000 a day, 11,400 a hour, 190 a minute - and that's assuming we are planting 24 hours a day, seven days a week.
It's not real. It's fake news. I defy anyone to explain to me how that is possible.
So how many trees could you plant a day, even if they were seedlings? Could you do 20 an hour? One every 3 minutes, and if you could, how long could you do that for? So on an average day you would do 160 a day. Even if you were doing that, you would need 1700 people doing that at the same time all day every day.
It's not possible.
Maybe in North Korea or China or Russia it's possible if you had the military seconded and slave camps operating.
But here in labour-regulated, time-and-a-half New Zealand, we are not planting a billion trees in 10 years.
So how is it this stuff is put out there with any level of seriousness, and passed off as a genuine government policy?
And more importantly, in the real world, just how many trees are we planting?
Does any one know, or is that part not as important as a headline?