I am no expert or anything, just want to mention that Sequoias need fire to grow. Their seeds usually survive fire and afterwards, new growth is triggered.
This does not mean that human-made fires are good. At this point, any additional release of CO2 is pretty bad.
Yes, but they are adapted to relatively frequent but lower intensity fires. As the article says, for the last century there was a policy of fire suppression, so the "undergrowth" (and from the perspective of a Sequoia, pretty much everything else is undergrowth) is much more dense than it usually was. So if a fire gets out of control, it may get more intense than the Sequoias are adapted to.
This does not mean that human-made fires are good. At this point, any additional release of CO2 is pretty bad.