Scott, I've seen this too and it only tends to be noticeable with certain varieties. It seems especially common with my red grape tomatoes and the Bumblebee series. Those are also the same varieties that are quick to regrow suckers from the same joints, often in multiples. So I'd attribute the problem to variety differences, possibly stimulated by initial pruning. Naturally since the leaf cannot easily support the extra fruit weight and it leads to a very dense foliage canopy I try to remove all that I see.

Do not feel any guilt ridding your yard of this maple: it is a cultivar of the Norway maple, which is considered an invasive pest species. Here's a quote from the Western Oregon University: "The Norway Maple is an invasive pest that should be discouraged from growth." The purple form is commonly planted in suburban yards, and escapes by seeding itself all over. You would be helping the local environment by "discouraging" it from growth. Yes, the ginko and european beech are also not native, however, they are not known to reseed themselves wantonly around a neighborhood, county or state. Although beeches have very thirsty roots too, just thirst is not the point here; when it comes to competition for the entire environment , the Norway Maple can out-compete almost any other tree (there are other tree thugs too that share this infamy). Sunny

Unfortunately, I agree with everyone who thinks this is water damage. In fact, if there is so much moisture that it is coming through plaster walls, then there is significant water infiltration and you have to get at the source. My first guess is that it is one or more roof leaks, and once you get that fixed, the problem is that you may well have major structural wood rot inside the walls and mold. It's entirely possible that the plaster will have to be removed from the walls, the rot and mold would need to be removed, and the walls would then need to be re-built. I don't want to sound like an alarmist, but I suspect this has been going on quite a while inside the walls and you need to be prepared for what you might find and what it might cost to fix.

Looks like a fungus infection. You don't mention your growing conditions, but usually they start with overhead watering or spraying, high humidity, not enough air movement and not enough sun. Tell us more about your growing situation and we may be able to help more.