Chapter 14 Tree or Not Tree?
...So, let's get back to why the roots are the most important part of a tree. Conceivably, this is where the tree equivalent of a brain is located. Brain? you ask. Isn't that a bit farfetched? Possibly, but now we know that trees can learn. This means they must store experiences somewhere, and therefore, there must be some kind of storage mechanism inside the organism. Just where it is, no one knows, but the roots are the part of the tree best suited to the task.

...But a brain? For there to be something we would recognize as a brain, neurological processes must be involved, and for these, in addition to chemical messages, you need electrical impulses. And these are precisely what we can measure in the tree, and we've been able to do so since as far back as the nineteenth century. For some years now, a heated controversy has flared up among scientists. Can plants think? Are they intelligent?

Chapter 16 Carbon Dioxide Vacuums
When the largest coal deposits were formed, in the Carboniferous period, carbon dioxide concentrations were much higher - nine times today's levels - before prehistoric forests, among other factors, reduced carbon dioxide to a level that was still triple the concentration we have today.

When I was a student of forestry, I learned that young trees are more vigorous and grow more quickly than old ones. The doctrine holds to this day, with the result that forests are constantly being rejuvenated. Rejuvenated? That simply means that all the old trees are felled and replaced with newly planted little trees.

...In fact, past scientific assumptions in this area appear to have gotten ahold of the completely wrong end of the stick, as suggested by a study(*) undertaken by an international team of scientists. The researchers looked at 700,000 trees on every continent around the world. The surprising result: the older the tree, the more quickly it grows. Trees with trunks 3 feet wide generated three times as much biomass as trees that were only half as wide.
...Since the publication of this study, the exhortation to rejuvenate forests to revitalize them should at the very least be flagged as misleading.
...If we want to use forests as a weapon in the fight against climate change, then we must allow them to grow old, which is exactly what large conservation groups are asking us to do.