There's an episode of Grand Designs (season 10 or 11 IIRC) where the couple building the home chose Japanese larch for the cladding for their home in Wales. The specialist lumberyard used some sort of handheld tool to measure the density of the trees (harvested in Wales) and it was extremely strong ... but the show also noted the strength could vary widely from batch to batch, depending on variables such as age, soils, etc.

Some details: http://www.cilfiegansawmill.com/forestry-wales/