After hours of searching I did find somewhere that this is due to a fungus.

Looks pretty much dead, on its way from one Happy Valley to another. On another page Wikipedia says Happy Valley is the name of a garden in Stenness, Orkney, Scotland. The area was originally known as "Bankburn". It was created by Edwin Harrold, between the October 1948 and the 1990s from a bare hillside. Mr Harrold had to give up the garden, as he was too old to maintain it, and he died in 2005. Amongst his aims, was to create a wooded area on Orkney, as trees are highly unusual on the archipelago

Eh, no, Grae. Per the thread, still quite readable, they simply don't grow at all well on the east coast of the US. Anywhere far north enough to be sufficiently cool in summer, they can't survive the winters for the long term. (there are odd reports of one on Martha's Vineyard that dies back in cold winters. Hardly ideal) For probably 40 years at least, fancy nurseries from DC to NYC have "imported" them from PNW wholesalers. Scarcely any over 4m in size are known. Almost all eventually die. In fact the one surviving in Silver Spring, MD, is in a somewhat shaded spot, and I believe that's true of the Baltimore tree too, although I haven't seen it in person. "Large trees soak[ing] up huge volumes of water" is probably beneficial for the survival of a summer dry species, when trying to grow it in a climate where tropical storms can drop 20cm+ of rain at a time! Coupled with extremely high temperature, it fuels the root rot organisms that kill them.

I actually don't think it had anything to do with the polar vortex winters; or their effect was minimal. I saw the almost 50 foot Bethesda tree after the 2nd winter and it looked just fine. Cevi is not reporting that it had extensive, visible damage after the polar winters and I doubt it did. " In fact, last year's rain was well over the average for this area, but without any flooding in this garden." This is the far more likely explanation. We had one of the wettest early summer periods we'd had in years. Allowed Phytophthora root rot sp. to really go wild. In late June/early July I lost a grafted magnolia that was in a slightly poorly drained spot. A few rare Asian cloudforest/alpine perennials died. etc. etc. Araucaria araucana comes from a climate with crisp, cool, dry summers...nights in the mid 40s, if not cooler(!)...and is almost always going to be prone to sudden failure in a climate with hot, wet summers. The 4 or so known large trees in the mid-Atlantic are rare exceptions if you consider how many hundreds or even thousands have been sold by high end nurseries over the past 40 years. There should be one in every upscale neighborhood, there most definitely is not. Funny enough I am aware of another tree in Columbia, near one of the lakes, that was about 8-9' when I moved from there in 2006, but died 2 or 3 years later. They usually die 2 to 5 years after planting, consider yourself lucky that you got more. If you look at how different the climate is where they originate, it's kind of amazing they last _that_ long around DC.