It's been a brutal forest fire season in California. But there's actually a greater threat to California's trees — the state's record-setting drought. The lack of water has killed at least 60 million trees in the past four years.

Scientists are struggling to understand which trees are most vulnerable to drought and how to keep the survivors alive. To that end, they're sending human climbers and flying drones into the treetops, in a novel biological experiment.

By Mark Muckenfuss

It’s a bit of a whack-a-mole kind of thing.

One invasive pest gets knocked down, such as the European grapevine moth or the red palm weevil, and another pops up.

This time it’s the South American palm weevil, an inch-and-a-half-long black beetle that loves Canary Island palms – like those lining Riverside’s Victoria Avenue – and kills the trees within months. The top fronds of the tree die and fall off, leaving the tree looking as though it has lost its crown.

By Chris Mooney

Healthy forests are especially important at a time of climate change — they’re an incredible tool to remove carbon dioxide from the atmosphere. Dead forests, on the other hand, can light the spark for wildfires, which are already showing a long-predicted uptick in activity.

Akif Eskalen steps through the dense, damp leaves in a wooded neighborhood, scrutinizing the branches around him. He's looking for evidence of an attack: tiny wounds piercing the bark and sap dried around them like bloodstains.

The victims are box elders, sycamores and coast live oaks, all in some state of suffering. Eskalen approaches a tree riddled with 1-millimeter holes, as if someone used it for miniature target practice. It's time to nab a perp. He selects a hole, pulls out a large knife and expertly levers out a chunk of wood.

the guardian-

As farmers abandon crops amid dust bowl conditions, scientists find ways to fighting contagious spores of 'sudden oak death'

California's drought is worsening and turning farms to dust, but it is also helping to save oak trees from a deadly fungus and keep beaches clean from bacteria-saturated water.

The lack of rain has impeded a disease which kills the state's signature tree and reduced the amount of bacteria-laden water which contaminates the coast, according to reports this week.