Question
QUESTION: We have a huge, maybe 50 ft tall, tree that is suddenly losing it's leaves.  This tree has rather "molted" smooth bark, round hairy balls for seeds, and a maple like leaf.  Just today I noticed the leaves are drying up and falling, very rapidly I might add.  The tree is covered with the round balls and looked just fine until now.  Several smaller trees have died on the neighbors property in the last year.  This tree is way over 23 years old, was a big tree when we moved here 23 years ago.  Like I said it has rather silverish, molted, smooth bark.  The trunk of it is very long and straight before it gets any limbs on it.  Any idea what might be causing the leaves to dry and fall like this?  I'm hoping it's not some blight running through the neighborhood.  Thanks for any information you can give me.

ANSWER: The first thing to look for is a wound in the trunk area.  Large splits or cracks will weaken the tree's ability to take up water and the result will be falling leaves.  Otherwise look at the leaves and see if they have brown spots or blotches on them.  The tree could be a sycamore or cottonwood based on your description.  The sycamore is susceptible to anthracnose, a fungal disease of the leaves.  It causes defoliation, but I doubt it will kill the tree.  Keep the tree fertilized and watered during perios of dry weather.  I hope this helps.  Thanks.

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QUESTION: Ok, I checked some pictures and this is a sycamore tree we're dealing with here.  I also looked at alot of the fallen leaves, everyone of them has a powdery white fuzzy something along the veins on the back of the leaves, some have a great deal of it, some just a slight line along the side of the vein but all have it.  The tree itself looks good, no cracks or missing bark.  Do you still think it's anthracnose? Thanks so much for your help.

Answer
Not anthracnose.  That disease causes big brown blotches on leaves.  The white powdery stuff is normal.  Something else is causing the tree to defoliate unnaturally.  Check the trunk for splits and cracks and see if there is some wound on the trunk. I can not think of anything else that would cause defoliation at this time of year.