This article appeared in The Economist and sums up the need and benefit of thinning the forests of the Sierra Nevada. I’ve added a few comments about it below.

The larval form of bark beetles are what kill the tree. The adult beetle chews a nursery gallery into the tree and lays her eggs. The larva hatch and spread out from that gallery creating more galleries as they feed. During this feeding process the larva girdle the cambium of the tree causing it to die.
I really appreciate the discussion regarding water generation through thinning. I believe this is one of the least discussed benefits of practicing forestry in the West, but in California it’s one of the biggest benefits with our constant water deficits. Thinning the Sierra forests would generate an enormous amount of water for California.
When comparing the cost of controlled burning to mechanized thinning (logging) you can’t ignored the cost incurred when controlled burns get out of control. The cost differences between doing controlled burn and fighting out of control fire is enormous. I’m not saying don’t use controlled burning, but fire suppression costs need to be included when controlled burns get out of control. Controlled burning is one tool available, but cannot come close to solving the problem of all the overstock forests.
Commercial thinning that includes merchantable (larger) trees is the only economically sustainable way to accomplish the massive level of thinning that needs to be done. The author points out 52 trees per acre was the historic density of trees in the Sierra. Research has shown that the proper density for optimal growth in fully stock mature timber stands to be between 43 and 64 trees per acre depending on the size of the trees. If we remove 236 trees per acre to reach 64 trees per acre, then some of those trees have to be big enough to make a 2 x 4. If there is enough value in the larger trees, a timber company will pay the federal government to thin the forest instead of the government paying a contractor to clean up and dispose of the unmerchantable trees.
What’s the upside? We get healthy resilient forests that are more fire resistant. Wildfires that do start are less severe, and safer and easier to control. There is more water available to the state. The wood isn’t left to rot. It is used in wood products and to generate electricity. People doing these forest related jobs see an economic benefit, particularly in the rural communities. The practice is sustainable and wood is our great renewable resource.
Lastly, some folks are going to fret over the impacts of logging at that scale. I want you to know this, timber harvests are studiously planned to mitigate the potential negative impacts they could cause. Secondly, just imagine the negative effects of these mega-fires. I’ve seen them and their effects are staggering. I’ve yet to see one large burn ever have it’s negative impacts fully mitigated.
Interesting topic! And a scary one. When there’s not enough water to even water the trees.. I feel there’s a bigger problem here. Can irrigation of lawns be banned? Pools banned? I feel sometimes folks don’t want to sacrifice their yard, but it’s OK to cut down a forest that’s out of sight. I get thinning forests, but I feel it’s a hail Mary pass.
As a Midwestern arborist, I don’t have to think about these types of concerns… I’m also more of a planting/care arborist 😆
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The water use for lawns and pools is all downstream of the forests, so water usage has zero impact to the forests. California has ignored the water issues for so long knowing these droughts are cyclical. So much of our water problems can be laid at the feet of the state government. Californians have cut their water usage quite a bit, but the population continues to grow. Thinning is a win win for our forests. These western forests evolved with a fire ecology. The repetition of low intensity fires of the past maintained low tree density. Thinning is how we can return the forest to their historical stocking levels. Even if we want to use prescribed fire, we would need to thin the forests first in order to achieve low intensity burning. Otherwise we burn up too many trees. Thinning is needed regardless for forest health, but more water is a great byproduct. Our biggest forestry issue in the west is that we have too many trees on the landscape, with the exception of where the wildfires occur.
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In Australia water restrictions, including not watering lawns, and limiting pool top ups, is a regular feature of our summers. When we are in a big drought everyone seems to pull together. Our city reduced even
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Sorry hit the wrong button before i was finished. I was saying that we reduced our water usage much more than we were asked to. What has changed is general landscaping. People are finally getting the message that a lawn is not necessarily maintainable. Many have swapped to mulched gardens rather than fight the losing battle for a patch of grass. What is even more promising, from my perspective, is that our city government has established baseline water restrictions for all summer usage. If necessary these can be escalated, but it does send a message that we cannot afford to use water thoughtlessly. OK getting off my high horse now! Merry Christmas.
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It’s pretty much the same here now. About two years into this drought nearly every lawn was brown expect for around government building, go figure.
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Folks did better at controlling their water use with this drought, but it wasn’t easy. Everyone was pretty used to getting all the water they wanted. Now a lot of lawns have been replaced with wood Chips.
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I think the point is to thin the forest to create a better one and improve water supply simultaneously while using an economicaly viable model to achieve this. I don’t understand how that’s a “Hail Mary pass”.
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Exactly right Kristo.
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I hope you and yours enjoy the holidays! and…

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Thank you Gail! Merry Christmas to you and yours. And of course our troops!
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So enjoyed your post. Fascinating!
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Thanks Don!
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Merry Christmas Tim! Looking forward to reading you in 2017! From a forecast 32 degree C Christmas day in sunny Australia.
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Thanks Leonie and Merry Christmas! 🎄 sounds nice down under. Makes me want to jump on a plane.
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You’re welcome any time!
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Thanks Leonie!
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