The perils of large deforestation around the world

Editor’s note: This is part of a series of opinions submitted by Mariposa County resident Jon Wenzel.

The California drought of 2012-2016, scientists say, was much stronger because of carbon dioxide in the atmosphere reflecting more heat back to Earth. It was the hottest drought in California history.

Scientists concluded that the drought was one of the worst in the last 1,200 years based on tree rings.

The western pine bark beetle (Dendroctonus brevicomis) plays a very important part in keeping the forest healthy. It kills unhealthy trees that can not secrete enough resin, not sap, to bleed out bark beetles while healthy trees produce enough resin to kill them.

In the drought years of 2012 to 2016, trees could not produce enough resin, because of the lack of water and beetles thrived, killing 90 percent of large Ponderosa pines in some areas of the central and southern Sierra Nevada.

Resin is a thick and sticky substance produced by the tree when it is injured. It seals wounds and bleeds out or drowns pests. Sap is thin and watery. It circulates a sugary liquid full of nutrients.

Resin, which is yellow or brown, seals wounds and bleeds out or drowns bark beetles. Sap, which is golden brown to amber, is the blood of the tree.

Pine beetles attack a stressed tree and use pheromones to attract more beetles and create a mass attack. The excess heat, caused by the effects of global warming, stressed the Ponderosa pines to the point that even the large trees could not produce enough resin to bleed out the bark beetles.

The winters were warmer and did not kill off much, if any, of the beetle larva. The bark beetle population exploded and killed nearly 62 million trees.

Resin is a thick, sticky substance that a tree produces to seal wounds and protect the tree from bark beetles. Sap is like water that carries nutrients and sugars throughout the tree like blood in your body.

During the drought, the pine beetle killed 10 times more trees than in the past decade. They also killed trees in heat and water stressed forests of Colorado, Arizona and Montana.

The enormous amount of trees killed became that much more fuel for forest fires. More intense forest fires release more carbon into the atmosphere. Winds carry the fire soot to glaciers. The black soot on glaciers absorbs heat from the sun that melts glaciers faster that creates more open land to absorb more heat.

The more heat the more beetles that survive to kill that many more trees. A never ending cycle that is created by too much carbon dioxide in the atmosphere.

Seven logging trucks full with 18 inch diameter and larger logs were taken off our property. All Ponderosa pines.

When we bought our place 45 years ago, one of the biggest selling points was the many trees. Now I can count less than five large pines left.

There is one Ponderosa pine that died in the top 10 feet. I deep root watered it 24/7 for two years and saved it. It produces more and larger cones now than in 1980.

The high tree mortality, mostly Ponderosa pines, left large amounts of dead wood creating fuel for wildfires. The mountains near us are covered with thousands of dead trees.

A study done at UCLA in 2021 showed that human caused warming was the main contributor of increasing wildfire probability in the Western U.S., namely California. Warming temperatures added an 80 percent increase in the dryness of the atmosphere between 1979 and 2020.

Reports from the California Department of Public Health (CDPH), Think Hazard (thinkhazard.org/en/about), the state level California Climate Change Assessments and the Community Wildfire Protection Plan (CWPP) help CAL FIRE to be prepared to defend areas that show a possibility of heat waves and changes in rainfall.

The more CAL FIRE knows about the conditions that cause high probability of fires before they happen the more chance they have of possibly preventing it happening. The more information you have the better you are prepared to deal with the situation.

Finally: The burning of fossil fuels causes the heating of the atmosphere, causing droughts, causing huge amounts of bark beetles to survive, causing more dead trees, causing more fuel for forest fires. Forest fires are a form of deforestation.

The more trees that burn, the less carbon dioxide is absorbed. Forests absorb 30 percent of the carbon dioxide in the atmosphere. That’s a 30 percent loss to heat up the Earth.

In 1974, the world population was four billion. Earth can support four billion. Today, there are 8.2 billion people which puts stress on all of Earth’s resources.

The number one cause of deforestation is overpopulation. Huge parts of the world’s forests are cut down to clear land for growing more crops to feed the overpopulated areas. More land is cleared for livestock ranges. More trees are cut down to build more housing for more people.

When a tree in the Amazon rain forest is cut down, it is one less tree that could collect and store carbon dioxide and make the Earth that much cooler. Photosynthesis is done by trees as they absorb energy from the Sun’s radiation to convert carbon dioxide and water, from their roots, into sugars to feed on.

They give off oxygen as a byproduct. If trees did not give off oxygen as a byproduct, we would not be able to breathe. Our lives depend on trees.

Deforestation in the Amazon can release diseases such as Chagas disease, which can cause heart failure, sudden death and or obstructions, partial or complete blockage that prevents the passage of food or stool, in the small or large intestine and neurology problems.

Also, malaria, which can cause failure of the liver, kidneys, and lungs, brain damage or death. Hantavirus can cause kidney failure and pneumonia. Spotted fevers that can cause organ failure, brain inflammation and death.

Ebola outbreaks in Africa have been linked to deforestation. It causes internal and external bleeding, including from your eyes, nose, gums, small and large intestinal. It can damage the liver, kidneys and lungs. There is no cure for Ebola so you could easily die from it.

Scientific evidence shows that deforestation and other habitat destruction can create the conditions that can release the coronavirus that caused Covid-19 to surface and spread from bats, or other animals, to us. Deforestation causes the destruction of animal habitats. This forces wildlife into closer contact with each other and humans. This gives pathogens a chance to come out and spread.

In 2005, a Swedish-British billionaire paid $14 million for 400,000 acres in the Amazon rain forest. He bought it to protect it from being logged and also protect the indigenous people.

These people are considered guardians of the rain forest because of their vast knowledge of its environment. They are defending their homes from deforestation and illegal activities.

I just read that the first climate tipping point, the point of no return, has been crossed. The widespread death of warm-water coral reefs.

The Guardian reported on April 23, 2025, that more than 80 percent of all coral reefs are bleaching and dying.

Scientific American printed an article on Oct. 13 titled, “Coral Dye-Off Marks Earth’s First Climate ‘Tipping Point,’ Scientists Say.” This report is based on the Global Tipping Points Report of 2025 that was put together by 160 scientists from 23 countries.

I will talk about the above and other close tipping points next time.

Jon Wenzel is seeking other individuals interested in this topic and he can be reached at jondwenzel@gmail.com.