Are not the soils in New Hampshire granitic in nature? This leads me to
believe that the 1 - 2% CaO in decomposed granite would be a much
greater source of Ca for the trees, if it were bioavailable to them,
rather than the rain's Ca. Other sources would include the excrement of
bird and other fauna, dead animals, decaying vegetative matter.
I know that my organic tomatoes could not possibly thrive on 0.8 ppm Ca.
Every plant is different, but hydroponic tomatoes are commonly fed over
200 ppm Ca. I've measured the leaf tissue of my tomato leaves at 2.26%
Ca by dry weight. (I grow organic soil-based tomatoes for a living using
rain catch and have had major Ca deficiencies, so I think about all this
a lot and test for it.)
If you want to read about what I do with all that sweet rainwater
flowing into my tanks, check out: