Podcast Episode #14

For complete transcript of this episode please visit my website Treesmendus.com
Visit Joanne Maloof at oldgrowthforest.net
Joan's book and my book.

Let’s talk about what an old growth forest is, and how this fits with  the  raging forest fires in Oregon and Washington as we speak. 

Yes if you think of the planet earth, at least  a third of it is  covered in forest. With this forest certain places do well naturally  with enough rainfall and enough soil – those forests don’t need to be managed in any way. In fact if you look at the  forest with the biggest trees – I was just in Sequoia National Park – those are the forests that are not touched by humans. That would be what I am calling an old growth forest. Some people used to call them virgin forests, or primary forests, but they are just a wild forest. These forests have had no disturbance from humans. Now that does not mean that they have not had any disturbance. They could have tornadoes, ice storms, and  fires  coming through. But some of those forests that have  escaped those things have existed for many hundreds of years or thousands of years,  and that is an old growth forest.  Or if one of these forests was disturbed even by humans, many hundreds of years ago, and has grown back naturally, we also call  those old growth forests. 

How that relates to the fires…is that the old growth forests tend to be very damp places, now this is a generalization but they tend to be much damper than a forest which has been cut. This is because you have many layers in the tree canopy, mosses, thick soils, and that moisture in the forest prevents those intense fires. Also the older trees have much thicker bark. So even if a fire does come through, the tree is more likely to survive it. 

But what happens where we have cut those old growth forests, and have been planted or we let those trees grow back, those trees are a lot closer together. And naturally as a forest lives, those forests will thin themselves out, and some will die… then you have what we call “dog hair.” Those trees are so small and so close together, and those fires can burn very quickly and intensely. So when we think of the tree plantations, those commercially logged lands, that is where the forests get much hotter. Hotter fires can spread faster through the homes…So when we hear forest fires, some people imagine this fire and the whole forest burns down. That is not usually what happens. A fire moves through often starting on the ground, and hot enough to burn through some small things on the ground but not hot enough to burn through the bark. Then it might hit one of these plantations, where the trees are very young or thinned out, and it is drier. Then the flames will get much larger. Especially if there are dry conditions and a wind, the fire can get so hot that it can burn even the wild old growth forest. So it is very complex. If you look at a landscape where a fire has come through, it is not all even. There will be pockets where the fire was intense, and pockets where the fire has hardly burned at all… and the forest is going to recover very quickly. 

See complete transcription at Treesmendus.com