Just some thought off the top of my head....
Pros and Cons-
Are they harming or helping the trees right now. They're providing shade. Will your trees benefit from having shade right now or would it be better to have plenty of sunlight now to warm them up? When trees in your area get shade do they develop molds, mildews, bug habitats that cause harm? How about this summer? As Amy mentioned, will lots of other stuff blow up against them create more shade and/or more weight on the lower tree limbs? Or will they benefit the trees right now and dry up more during the summer and disintegrate? Don't create work if you don't have to.
As Anne alluded to.... it creates a habitat for creatures. In my neck of the woods I seldom see a poisonous snake and snakes are a good thing, a great thing. In the spring I see a lot of gopher snakes which eat gophers,
mice and rats and other stuff. Snakes are my friend. (I'm just careful not to step on one or reach down and grab one by accident) I only occasionally get a gopher or rat in my
yard. But the tumbleweeds create habitat for all kinds of creatures like
rabbits, rats, quail, groundhogs, etc. Didn't you mention recently that you have lots of animals helping themselves to your garden. In that case it's best to keep the ground-level clear of stuff so they don't have any place to hide. Of
course birds love that kind of habitat if you're into them.
If it were me I would consider all the pros and cons I could think of. Then decide... are they a good benefit to the trees right now or not. If they are good now can I wait until fall to see what happens. (A new experiment) If they are not so beneficial now then I would think.....I have been given a
gift! Free stuff! How can I put this
gift to good use. Boy I never toss anything away. How can I
reuse, recycle or re-purpose this! As Phil and Amy mentioned they can be a great source of free mulch. Make a pile and throw a tarp or some
cardboard over them and roll around on it to crush them down, something the kids can help with. Mulch the trees or make a path. Do you have a bare spot where nothing much grows? Sprinkle them all around and by this fall you will see weeds and grasses growing there. Conditioning the soil.
At least, that's what I would do. But I know some of my crazy neighbors here in Sedona would probably spray paint them all kinds of crazy colors and make a huge pile of them in their front yard and call it
art! And then some other crazy person would probably come along and give them big bucks for it! Well, each to his own! Happy
gardening.