A: When it's mitey.
To find the root of this seemingly nonsensical riddle, we need to go back a couple of summers, to the time my partner and I first moved into our house. The biggest attraction (literally) was a huge old Aleppo pine that dominated the front yard, with a 3-foot-diameter trunk and a massive canopy that shaded much of the roof. A similar giant loomed next door, creating a miniature oasis of pine forest. Goldfinches gathered in the high boughs every day, and sometimes, Cooper's hawks and kestrels lurked there. Every now and then, we would hear the eerie hoot of a great horned owl outside the bedroom window.
Alas, our beloved tree must be described in the past tense. Not long after we moved in, I noticed a barely perceptible fade in the normal deep-green needles. I might have chalked it up to the ongoing drought, but the monsoon had been a ripper, so the timing seemed curious. After another month, it became clear that my eyes were not deceiving--the tree was yellowing. By winter, all of the needles were brown, and many had fallen off. The tree appeared to be dead.
The property managers sent a tree doctor to confirm mortality but didn't authorize him to determine the cause. By May, the nearly naked limbs drooped sadly, yet a pair of verdins still nested in them, low enough for us to peer in and see their eggs. Then the undertakers came to saw down the massive wooden corpse and carry it off.
As this tragedy lingered, I began to notice other large pines around town in similar straits. Looking for a pattern, I inquired with a few tree-removal services. The general indication was that they were taking down about twice the number of these behemoths as they had in years past, but no one could tell me why. Was it the drought? Or a pathogen, as the tree doctor guessed? Or maybe just age. Many Aleppo pines, a fast-growing, drought-tolerant Mediterranean species, were planted in central Tucson more than a century ago by settlers desperate for shade. Perhaps the oldest were simply nearing the end of their life spans. As the broad stump weathered in the front yard, I continued my investigation, inquiring at the UA for some research into the problem, without success.
I resorted to the Web and found a paper by a certain Andrew Backhaus, Ph.D., who observed that Aleppo pines were indeed crashing hard, and not just in Tucson, but Phoenix and elsewhere. He acknowledged theories blaming fungus and drought, but then detailed the detective work that had led him to what he believed to be the real answer: He called it "Aleppo pine blight" and blamed it on a mite. He described how tiny bugs were colonizing the massive trees and causing much of their foliage to turn brown over the winter, to the point that some trees appeared totally dead by spring. But here's the kicker--the trees weren't really dead! By May, fresh new needles would replace those that had died off.
I followed a link to Artistic Arborist Inc., a Phoenix tree specialist. I got "Tim" on the phone and grilled him on this latest revelation. He agreed that the mite was a big problem but probably had not been the culprit with our tree. There were several other possibilities; unfortunately, it was expensive to get a forensic analysis done on a year-old stump, so our case would remain a mystery.
But he did give me a moral for this fable: He said that too many unprofessional and/or unscrupulous tree-removal services were taking down blight-infested trees that were still alive. He recommended getting a second opinion and taking a close look at the tree's condition before cranking up the chainsaw. Considering the incredible value of these trees, it seems like good advice. Another study I found gave a rough estimate of $20,000 per tree in environmental services alone (shade and cooling, water retention, etc.), above and beyond their aesthetic value.
So if your mighty tree is turning brown, don't be too quick to cut it down! It might just be mitey.