Why are trees dying?

I took a walk around my block last evening and noticed alot of mature trees in seriously bad shape. My neighborhood is one where normal homes are being torn down and replaced with enormous ones. Each of the new homes had trees in terrible shape. I know that during the construction phase, at least some care was taken to avoid stressing the trees so I don't think it is soil compaction or even root pruning. My next door neighbor has one of the new huge homes and the contrast between the trees in his yard and in mine is dramatic, especially the oaks but also the white ash are failing. Could it be that trees don't like lawn sprinkler systems?

I wouldn't rule out soil compaction or other construction related damage--mature trees have rather large root systems and unless the lot is large and the trees are way far from the house, it would be very easy to do some damage even if you think you're being careful. The fact that it's all the newly constructed homes that have trees in bad shape tells me that it is most likely linked to the construction in some way. I'm assuming some of the older smaller homes also have lawns, so if it were an issue of the trees not liking the amount of water that the lawn gets I would think everyone's trees would be having issues not just the new houses, or at least you'd see a mix of old & new houses with issues.

Oops. I guess I should have clarified my opinion that I don't think it was construction traffic instead of just saying it wasn't. The trees are mostly at least 30' from the homes - way more than the canopy radius of any of the trees in question - and since large areas of the yard around trees were roped off to prevent any construction traffic on the root zones I don't think it was the construction compaction. Typical lot sizes here are much bigger than they are in the west and in our part of the country, lawn sprinkler systems are extremely rare in homes constructed before about 2000 so the only lawns getting that kind of water are the new ones I described. The typical lawn for older homes here is a diverse community of clover, "weeds", and several kinds of grasses. The newer homes have only fescue lawns and use weed and feed types of herbicides to keep it that way, and then water heavily to keep the fescue emerald green and lush even in August. . . . But, the city water is pretty heavily chlorinated and treated with other kinds of chemicals to prevent algae (and my plants don't like it as well as the water from my rain barrel) so it might be that the water is just not very healthy for the soil rather than the amount of water being more than the trees can handle or the method of watering being too shallow. . . . Anyone have experience and expertise on this topic?

I just read an article about this same thing, it said the trucks & piles of debris have to be at least 30 feet from the mature trees to keep from damaging them. It's a shame. They best watch for dropping branches.

bade we cross posted :) 30 feet, magic number? Maybe digging up for the sprinklers did it. trees don't like their root systems disturbed. If I find the article again I'll post a link.
I'm pretty sure I read it online.....

Thanks Lynnie. It would be very interesting to see that article. I do know construction is not good for plants but my instincts tell me there has to be more to it. My neighbor told me it was an oak disease but mine are healthy. I can't believe that a disease would respect property boundaries! I've had several remodeling projects over the years where they really trashed my entire yard, driving heavy trucks and such over it to the point where it was hard as a rock with no grass at all - in fact, the year my neighbor built "Graceland" next to me, he drove his old house over my yard on a big truck and it was so heavy it sank into my yard up to the axles! And one year I even had *really* heavy duty machinery on my yard digging, trenching, and drilling deep for a geothermal HVAC unit. (After that one I admit I had a company come in to run a harley rake across the lawn areas and treat the lawn with some macrobiotics to help deal with the compaction and the sub-soil that had gotten put back on top.) The only other thing I can think of is that all these trees on the big house lots are aggressively limbed up to avoid having too deep of a shade problem for the landscaping. Maybe they just can't photosynthesize with so many fewer leaves.

bade I didn't want you to think I forgot...I searched online but was unable to find the exact article....the point of it was to get a landscaper in there before starting to build to try to save any mature trees, and even then it would be tricky. If I do come across it I'll post it.

Surface roots can extend past the canopy. Sometimes covering an area as much as 3x the height of the tree. I lived on an acre of oak and hickory for 20 years. I moved in when the house was 3 years old. Trees closer to the house did exhibit stress from the construction. One oak in particular comes to mind. The tree guy trimmed it - no topping, just sized it down to a skinnier tree. Judicious trimming was done to others - similar to cutting back a transplant so the root system doesn't have as much plant to support while its getting re-established. Then I dug out the trunk to the start of the roots - it had been buried by the dirt movers. Added rocks on the side facing the ravine to preserve drainage to the roots if soil washed back over the cleared portion of the tree. Then watered it for a year or two. It came back full tilt and limbs returned to natural spread for its height.

I hope it's something that simple for the neighbors and not a water issue or disease of some kind (agree with you that this is doubtful)

~Sharon

bade, I have noticed the same thing in my neighborhood and seems to be hardwood only that is affected. I suspect an early fall and maybe trees are dropping their sap sooner than usual. I would hate to think all these nice trees are dying. The weather here this year has been great, no drought and just enough rain and the area that I travel has little or no construction. Go figure

Well, here's an update - my tree guy came by and said that the fact I have most of my trees growing in a natural forest type situation and haven't messed with them is the reason they are so healthy. However, we had a really severe drought a few years ago and some of my trees are now showing the stress, a couple of young Maples in the woods have lost their top leaders. He also says that my really huge oak that is right next to the house and has endured several construction projects is stressed now (although it looks fine to me). I did notice a freeze crack going all the way up (at least as far as I can see) the tree from the late freeze that followed the two years of terrible drought and the root pruning, etc associated with running the geothermal lines from the wells to my house. I probably won't take heroic efforts to save it, although it was strongly recommended to give it root injections of macrobiotics and nutrients for the next year. Maybe it is just the drought and late freeze and extra hot weather in recent years that made the trees unable to endure the stress of anything else piled on top of that.

wow Bade, that's amazing that a drought a few years ago can stress a tree for so long...it doesn't sound encouraging does it?

It happens, I know first hand. Had a beautiful oak coming down my drive. We had around three years of severe drought. The tree looked fine then just over night it seemed it turned brown and died, had to have it cut.