That is false.

These issues were known to the US Forest Service at least 20 years ago, and broadly speaking nothing was done about it.

Climate change is helping forest fires to ignite and burn hotter due to reduced moisture in both trees and the soil. To the extent that it may also increase the incidence of lightning, and thus the probability of naturally started fires, it can also influence the numbers of fires.

But gross mismanagement of forests for most of the 20th century caused by misguided ideas about what keeps forests healthy is what has led to an almost unimaginable pile of fuel sitting on forest floors that would never have existed in the past.

Read the article.

It mentions in multiple places that climate change is increasing the duration of the forest fire season and worsening conditions that promote wildfire.

The point of the article is that outcomes of poor forestry management practices (a build up of fuel that lead to truly enormous wildfires when they finally burn) were bad enough, and now climate change is dramatically exacerbating those effects.

As a result, changing our forestry management practices to adopt controlled burns, thinning, and other techniques, will be a critical element of climate change adaptation.

That's not to say we shouldn't stop CO2 emissions as quickly as possible to avoid even worse future effects. But we've already warmed the globe enough that adaptation is already necessary, and this is just one example.

This is certainly wrong. There were wildfires in California before global warming was noticeable.

Global warming is an accelerant, but not the root cause.

Climate change definitely contributes to the crisis, but ignoring other factors does not help us improve the situation. For example, Spanish settlers in California planted invasive trees not adapted to the climate and specifically the wildfires. When the fire seasons came, the invasive trees burned hotter than native trees, causing the death of more of the flora than was typical.