Your article (Aug. 27, 2016) effectively describes the specter of increasing tree mortality in the Tahoe Basin due to bark beetles. Unfortunately, while describing important factors causing the problem, drought and even-aged stands, it did not describe the root cause – human-generated greenhouse gas emissions. Again the “third rail” of climate change was not touched.

Attacking a problem without addressing the root cause(s) is doomed to failure. A clear-thinking plumber called to your home to fix a broken water pipe first shuts off the water. Only then can he pump out the water, fix the broken pipe, and address the flood damage.

In your article, forestry officials describe necessary, but not sufficient measures, to address tree mortality. They consist primarily of thinning operations. The root cause of the extraordinary level of tree mortality is human-caused carbon emissions, which increases temperatures (climate change), which exacerbates drought, which weakens trees, which amplifies bark beetle populations, which increases tree mortality. Look at increasing carbon emissions as a shot of steroids powering the bark beetle populations. Our greenhouse gas emissions, yours and mine, are the root cause and must be addressed, or, using the flooded house analogy, we will be trying to stop flood damage in our home while the water is still on, the pipe is still broken, and water continues to spew out.

Our dying forests are yet another clear signal of a dire climate emergency. For me, and I dare say for most Sierra residents, vast swaths of dying forests in the Southern Sierras are a powerful motivator to action. Environmental agencies, government, businesses, and we, the citizenry, can work together to reduce our greenhouse gas emissions. We can start by having real conversations about climate change. We cannot be afraid to touch the third rail — our forests are at stake.

Fred Roberts

South Lake Tahoe, Calif.