The image looks good. I think what is taking place is the IR filter on the sensor of the D7000 is letting enough red spectrum come through to create a reasonable exposure. This may be a change from earlier models. While IR wavelengths are blocked almost completely, near IR in the red spectrum is permitted to pass. The red spectrum for visible light normally ends around 650nm, but you still get some red all the way to 780nm.
I'm not seeing the glowing IR effect on the trees, or the dark lightless skies, which suggests it is false IR or red spectrum.
There is nothing wrong with what you are doing. It makes for some very nice images, and by swapping channels you can work with color. Just enjoy it and have fun.
If you were to try a strong IR filter as in my test, you would see no visible spectrum and much longer exposures.
We have a separate IR forum and you can see the difference in some of the images posted there.