Drought is causing more forest loss than wildfire or other factors in the Sierra Nevada

Excerpt from a Greenwire article. I haven’t read the study yet….

Study shows worsening drought threats to Western forests

Researchers found that drought is causing more forest loss than wildfire or other factors in the Sierra Nevada, with implications for how those forests should be managed.

GREENWIRE | Drought — not wildfires or logging — may be the biggest long-term threat to forests in part of the West, according to researchers from the Forest Service and two universities.

A research paper suggested drought is the main contributor to ongoing losses of dense conifer forests in the southern Sierra Nevada, speeding the conversion of land to nonforest or lower density woodlands. Drought and the beetle infestations it invites were more responsible than the combined effects of wildfire or forest-thinning, researchers said.

In the area the scientists studied, they found that about 213,000 hectares — or slightly more than half of the area that transitioned to nonforest — could be blamed on drought alone. Forty-five percent could be attributed to drought and wildfire combined, and 4 percent to when drought and mechanical activities like thinning coincided.

That and other findings, the researchers said, together point to a need to manage forests through a mix of prescribed fire, thinning in some areas that have grown thick for lack of natural fire, and leaving big trees in place to protect against wildfire and maintain wildlife habitat. It also illustrates the dire future that may await forests in dry regions as the climate warms and wildfires potentially increase.

22 thoughts on “Drought is causing more forest loss than wildfire or other factors in the Sierra Nevada”

  1. I’ve been told by foresters for 40 years that logging “mimics natural disturbance” and makes the forest healthier. They have this infantile fantasy that thinks that catastrophic drought, floods, fire, wind and disease that have grown healthy forest ecosystems for hundreds of millions of years no longer exists and our tree farmed forests will die unless they “mimic” these disturbances with no limits to how much you can run the chainsaws.

    So now here we are as the planet heats up with air pollution and our once vast blanket of forests that could absorb much of that pollution has been wiped out and replaced with tiny trees that can’t absorb and store anywhere near their original capacity and the whole landscape starts to unravel with:

    — More than a million acres of trees dying off from drought in Oregon in an catastrophic dry season just a couple months ago.

    — 200K acres of Washington’s “Evergreen State” lost to permanent deforestation every decade

    — In 2020 more acres burned in the PNW than all acres burned in the previous 35 years combined. These forest burned hotter and faster than ever before wiping out the most heavily managed forests just as much as protected forests.

    — 10% of all remaining ancient giant Sequoia groves destroyed due to wind driven firestorms that no amount of forest management can keep out of the crown of their canopies.

    — One of every 8 acres burning in California in less than two decades and most all of those acres lacking thick barked older trees that are resistant to fires.

    The list goes on and on. And clearly the warning lights are on the dash board, the engine is sputtering and the car is breaking down and Steve Wilent and all his deforestation buddies are still in the driver’s seat insisting that the only problem is we aren’t driving fast enough and if we just push down the accelerator a little harder everything will be fine. An extraordinary embarrassment and lack of intelligence beyond measure…

  2. Seems like this article misses the point about the nature of how forests grow. Like allocating death to a heart attack, when the true underlying cause is a poor diet, lazy lifestyle, and genetic pre-disposition to heart disease.

    A healthy forest is resilient against most forms of disturbance. We can point fingers all day long about how a given tree died. But that would literally be missing the forest for the trees…

    • Agreed… And the root of the problem is short-lived humans claiming that long-lived trees need to live less than 10% of their potential lifespan and lie down and and be more useful to our bank accounts sooner than later. So killing the forest to “save” it is how the industry forces that round peg into our square hole.

      As in a young overstocked stand of trees on the west coast of North America that’s barely a century old is fairly normal in terms of natural history and once that stand gets into the second, third, fourth or fifth century the amount of destruction from the forces of nature over that period of time will add up to a naturally thinned forest that is far better able to survive those periodic destructive forces than any forest modern humans have ever managed.

      But the foresters/timber industry wants us to anthropomorphize those forests and think that there’s no such thing as trees living longer than 65 years because they slow down and need to be retired and the sooner we can cut them down, the sooner we can prove that loggers are right and hundreds of millions of years of forest evolution is wrong.

    • >> A healthy forest is resilient against most forms of disturbance.

      That’s the point. Much of the forest in the Sierras is unhealthy. Thinning and fuels reduction would help them survive.

  3. Deane

    An extended state of drought is all the more reason for forest management. Overstocked stands need more water therefore they are more apt to die from drought weakening the vigor of the trees. You need to understand that photosynthesis provides energy/sugar/food for trees. Excessive competition between trees in times of extended drought results in dehydration much quicker when a stand is overstocked. Dehydration will shut down photosynthesis due to the lack of delivery of moisture, minerals and soil nutrients to the needles or leaves from the roots. Without photosynthesis there is no food from the leaves/needles to feed the rest of the tree. So the tree will eventually die of starvation if it doesn’t die sooner as a result of it’s low vigor and inability to resist attacks from insects, disease or even some normally inconsequential wildfire because there isn’t much cooling liquid in the cambium layer under the bark combined with excessive fuel in close proximity to the stem due to overstocking.

    It’s just not nearly as simple as the uninformed assume it to be. A real forester has invested his/her life into maintaining a healthy/sustainable forest ecosystem. Some of your accusations ring hollow in the realm of reality. Instead of cursing what you don’t understand try to learn why good and decent people devote their time to understanding the well validated science instead of cursing the darkness as you seem to.

    • Hey Gil, Go out into a closed canopy big tree forest with lots of dead wood in the driest most drought stricken part of the year and dig into the wood pulp inside large rotten snags or logs. and you’ll be able to squeeze moisture out of those logs even though there’s a drought. This downwood and shade is essential to the survival of forests during severe droughts and gives trees a better chance of surviving fires. This is how forests have grown and evolved for hundreds of millions of years.

      When you thin out a forest and remove all the snags and rotten logs and open the canopy up so sun the reaches the forest floor you dry out that forest’s soil and the trees can’t survive a major drought without the moisture in that rot from large woody debris, thus, the whole place burns way hotter and with higher mortality rates.

      But I get it, you spent your whole career claiming trees use lots of water and the more trees you cut down the more water is available, right? But that of course disregards what time of year that water is available and its quality.

      A clearcut or severely thinned forest will produce way more water in rivers in the rainy season. But it will produce way more salmon killing silt than unlogged forests too. But in a healthy forest the soil acts as a living sponge so there’s more water remaining during a drought, as well as more water absorption capacity in times of floods, which mean less mass wasting and cleaner water downstream after a heavy rains.

      And when it comes to being uninformed, you’re a retired forester in Mississippi, the poorest state in the country and you’re clearly not aware that scientists in British Columbia have put tracers in water and in the nutrients in the soil and have found that forest soils that haven’t been destroyed by logging are able to share the water and nutrients amongst different types of trees and plants roots systems thanks to fungal networks. What’s more they’ve found that when a stand of trees has too many stems the Wood Wide Web self thins and as those trees die off their resources are transferred back to the network as the leaves go from green to yellow to brown.

      Of course because you’re a “real forester” you’re going to pretend like forests wouldn’t even exist if we didn’t manage them. And when it comes to the latest science, that doesn’t count if it doesn’t support more logging. You and your forester buddies support each other with these kind of lies and outdated science all the time. So the forests need more people like you to retire, so at least thanks for doing that much.

      • Deane, who should take you seriously when every single post you make seems to be seething with hatred and rage. How does living in Mississippi have anything to do with the topic? Your incessant need to attack someone who doesn’t agree with your personally held beliefs (that tend to read like pre-written environmentalist propaganda designed to be distributed en masse by unsuspecting folks looking for an honorable cause) is tiresome. British Columbia and virtually the entire Western United States have an exploding drug problem capped off with a homelessness epidemic. Good thing that there is tons of money to go around or else it would be just like Mississippi, a state that could shelter it’s entire homeless population in a school gymnasium.

        I think a lot of what you write here has value and is accurate, but I cannot get over just how predictably hostile your delivery is. There is no possibility for discussion when the script is always “I am right, you are wrong, here’s why. And btw, your entire career is a sham too.”

        • Let’s keep focused on Forestry Gil… Stop trying to get away from what we’re here to focus on and get back to an intelligent discussion about the most recent findings in forest science! Or maybe your point is your emotional reaction is specifically because you lack knowledge of the latest forestry science?

          And while we’re at it, don’t you think its funny that your Anti-Proforestation website you linked to argues that logging forests is the only way to have a viable forest and yet the banner photograph of that website is a stand of pristine canopy that has never been thinned or managed? I guess the website builder didn’t get the memo about how stumps and canopy fragmentation is supposed to more beautiful then dense stands of closed canopy forest and the people paying for the website didn’t notice the photo for the website was antithetical to their outdated propaganda?

          • Again, attack first, ask questions later. Your assumption that I am Gil only furthers my point that you don’t actually care about what anyone else has to say and that any further discussion here is pointless. Like I said before, I agree with many of the arguments you’ve made but due to how you make those arguments, nothing will ever be accomplished. That is of course if the idea is to come to some sort of agreement on how we should go about sorting out this big mess we are all in… Otherwise, you’re spot on.

  4. I got my forestry training after Gil did, but it was pre “ecosystem management,” and there was still a flavor of “a dead tree is a wasted tree.”

    This article actually gets at a fundamental question that keeps coming up here, described in the article as:

    “As an alternative to the static approach to habitat conservation currently in practice, a landscape conservation paradigm that recognizes and incorporates ecological system dynamics (Hessburg et al. 2021, Gaines et al. 2022) may prove better suited for disturbance-prone forests.”

    “Perhaps foremost among these obstacles where sensitive wildlife habitat is of concern is that a managed dynamics approach appears at odds with the precautionary principle.”

    But it also points out in several places that the managed dynamics approach is not incompatible with preserving remaining refuges and “tall trees,” which is often presented here as being mutually exclusive:

    “Moving away from a “static” conservation paradigm in favor of a “dynamic” one does not prescribe eliminating protected areas or habitat preserves; nor would it involve removal of large trees, which our analysis shows supported forest resilience over the last decade. Rather it suggests greater active management is necessary (e.g., through fire use and
    ecologically based thinning; sensu North et al. 2021) with an eye for emulating fine scale
    heterogeneity and forest resilience likely supported by historic disturbance regimes (Jones et al. 2021a).”

    This recommendation seems to be 1) protect existing big tree habitat, and then 2) actively manage the rest to reduce fire risk.

    • Some of us are enlightened foresters, who do see value in snags. I’ve often told co-workers, “That snag is worth a lot more standing than in a cull deck.”

      And, what was that last count of snags in California? 130 million? I’ll bet it is a lot more than that, today, including the Caldor and Dixie Fires (among others).

      Additionally, salvage sales have become more like ‘snag thinning’, on Forest Service lands. There is no lack of snags in Federal forests. However, there is a level of tree mortality that severely impacts ecosystem function and services. It also leads to more damaging wildfire impacts, too, in re-burns.

      • Larry, I’m curious about your statement that there is a level of tree mortality that severely impacts ecosystem function and services. Timber sales, thinning projects and prescribed burns impact ecosystem function and services too, so it’s a matter of degree and land management goals. Are you saying mortality due to drought has a greater negative impact to preferred ecosystem function and services than more actively managed forests? If so, can you elaborate on those impacts?

        • I’m saying that when there are millions of dead trees, in a concentrated area, when they burn at high intensity, the soils undergo extreme damage, affecting ALL ecosystem services and functions. My Yosemite example is perfect for showing how forests can become longterm non-forest. Even the brush is having trouble growing in those damaged soils. “Natural Succession” probably won’t work in this example, and we’ll have to see what the combination of human-caused fires PLUS natural ignitions will bring to that landscape. There will be very little “Natural Succession” there, due to human-caused wildfires, burning during hot summer days.

          • I was a little confused since one sentence focused on mortality from drought and another on fire. Natural succession is occurring in all these burned areas, it just may not be occurring in our textbook way of thinking or according to our desires as climate change and drought also impact the trajectory of succession. I would expect this to happen in many areas regardless of the type of disturbance as changes in local moisture and temperature regimes will change what species of all sizes are favored. I think anytime we talk about forest health and forest resiliency, it helps to define what they are because really people may have different thoughts on them based on one’s values and land management goals. To be a bit anthropogenic here, nature doesn’t define forest health and resiliency, it just responds to conditions and sometimes it does so in timeframes and with species not to our liking.

            • When drought happens, plus the inevitable wildfires that come with it, losing mature seed sources has a major impacts on those forests. Couple that with the lack of planting trees on impacted acres and you have this current disaster of conversion from forest to non-forest. It is unclear whether currently dead forests will ever regenerate, due to reoccurring fires and drought. The idea that “Natural Succession” might take centuries is a non-starter. It is not ‘natural’ if man needs to intervene. It is not ‘natural’ if today’s human-caused wildfires impact that process.

              Finally, sacrificing forests in favor of the hope of “Natural Succession” is madness. That idea is more like the concept of ‘Whatever Happens is fine as long as we don’t intervene’. Yes, we CAN see Sierra Nevada forests are being severely impacted, and in some places, wildfires are the last option. What we do after that is up in the air. That is where the Caldor and Dixie Fires are today.

            • I would distinguish between “natural” succession and “unassisted” succession. We could not call it “natural” if the conditions under which it would occur were the result of human intervention (most obviously, fire suppression and climate change). I think that leads to management that tries to compensate for the prior human intervention, to put succession on a course closer to what would have occurred if we hadn’t screwed it up. (Of course, after considering any additional side effects of that active management.) (We could debate the role of native human intervention separately, but I think there is a difference in scale that is relevant.)

            • “… it just responds to conditions and sometimes it does so in timeframes and with species not to our liking.”

              We absolutely know how to grow large trees faster than “Natural Succession”, in the Sierra Nevada. Some people appear to not want that, in favor of ‘Whatever Happens’.


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