Should dry forests be considered suitable for timber production?

Recent research is showing that lower elevation forests are not regenerating after fires as they have historically.  From the abstract of the research cited in this article:

“Results highlight significant decreases in tree regeneration in the 21st century. Annual moisture deficits were significantly greater from 2000 to 2015 as compared to 1985–1999, suggesting increasingly unfavourable post‐fire growing conditions, corresponding to significantly lower seedling densities and increased regeneration failure. Dry forests that already occur at the edge of their climatic tolerance are most prone to conversion to non‐forests after wildfires. Major climate‐induced reduction in forest density and extent has important consequences for a myriad of ecosystem services now and in the future.”

One of those consequences should flow from NFMA requirements for sustainability and ecological integrity.  To put that in simplistic terms, if the land “wants” to be non-forest in the future climate, we have to let it be non-forest.  And non-forested lands are not suitable for timber production, regardless of whether we could plant and maintain a plantation there.  I don’t recall seeing any discussion of this in forest plan revision material I have reviewed recently.  There is also requirement to use the best available scientific information, so a suitability evaluation of low-elevation forests should go beyond what is currently growing there to address what would be expected there in the future.  Many national forests could end up with fewer suitable acres.

8 thoughts on “Should dry forests be considered suitable for timber production?”

  1. Good point, Such areas may suitable for a more adaptable, drought-resistant species. Or to a less dense stocking. My guess is that many acres in the southwest now classed as “timberland” will lose that status.

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    • Or they will just keep the acreage in the timber base as Lands Suitable for Timber Production. I would guess more than half the acreage of dry forests that have lands in the timber base do not meet the NFMA requirements of reforestation in 5 years. Probably more like 15-20 years.

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  2. Re: “Dry forests that already occur at the edge of their climatic tolerance are most prone to conversion to non‐forests after wildfires.”
    –> Yes, that is elementary – BUT – Since we know that forests create their own micro climates and a great many swear that carbon storage is essential to saving the planet from mass extinctions, it would seem that all of this shows the critical need to restore sound forest management to our federal forests in order to significantly reduce the risk of wildfire on these dry forests and all other federal forests and thereby maintain their micro-climate for as long as possible rather than resign ourselves to loosing them. When the climate cycle in the future returns to a more suitable state for those borderline forests, it will be much harder to convert them from grasslands back into forests than it would have been to maintain the forests that we have now using sound forest management practices. There is significant literature to support this fact about forest conversion in both directions.

    Re: “NFMA requirements for sustainability and ecological integrity.” – “There is also requirement to use the best available scientific information, so a suitability evaluation of low-elevation forests should go beyond what is currently growing there to address what would be expected there in the future”
    –> The “best available scientific information” tells us that climate change occurs in cycles and that there is no way to be certain as to what comes next, when or for how long.
    –> There is also a significant pool of scientists that believe that we are about to enter a cooling stage in the cycle based on the current evaluation of where we are currently in the well established solar cycle.
    –> The “best available scientific information” tells us that soil is radically altered by hot fires so as to be less receptive to natural regeneration – so – to lay the failure of regeneration only on climate change is “stab in the dark” defeatism.
    –> The “best available scientific information” tells us large wildfire removes a great deal of the acreage from adjacent seed sources – so – to lay the failure of regeneration only on climate change without considering the interactions between all of the ecosystem parameters (from the sun to the smallest soil component) is not sound science.
    –> Considering all of the parameters involved in evaluating “what would be expected there in the future” for such a large open ended system is pure guesswork based on one’s bias in forecasting all of the known and unknown parameters.

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  3. Foresters know how to adjust basal area to meet the conditions on the ground (and meet the needs of the land owner, etc.). That applies to all forests. In the driest forests, basal area will be lower, and in extreme cases trees may no longer grow at all. But until then, foresters will adapt actions to the site.

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  4. The NFMA states that unless regeneration can be assured within 5 years of harvest, timber harvest is not permissible. As those types of sites are identified, they are removed from the suitable timber base (the acres on which the allowable cut is calculated) due to “regeneration difficulty”. There are currently forests growing on sites that have soils developed under grassland – Mollisols. There were favorable conditions at some point for forest establishment. But when reforestation is attempted after a fire, it doesn’t succeed, especially in the midst of a drought. There are sites where a pine savannah is probably more appropriate than a pine forest, and those types of acres also need to be removed from the suitable timber base. Most of the incidences of reforestation failure that I have seen are at the lower elevation treeline – it’s not really a function of heated soil. It is reasonable that the lower elevation treeline will fluctuate depending on the conditions for forest regeneration establishment.

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    • “The NFMA states that unless regeneration can be assured within 5 years of harvest, timber harvest is not permissible.” That’s an arbitrary deadline and an unfortunate limit for areas where establishing young trees is difficult — and that can happen even on good soils with adequate moisture.

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  5. Long before I left the San Jacinto Mountains above Palm Springs California in 2002, I hadn’t seen new Spring seedling emergence along road right of way cutouts for a long while. You remember, 1000s of seeds always germinated in the past in such locations, but no more. In 1982, Forest Service Wildlife Biologist, Tom Roberts, of Idyllwild in SoCal told me all of those trees in the Strawberry Valley (entire town of Idyllwild) and the surrounding mountains would lose all their Ponderosa, Jeffrey and Coulter Pines in the future. He said the nly tree which would be tough enough to replace them would be Sequoia giganteum. Tom Roberts died late last year, hardly anyone remembers him in that area. At the time he told me this every little creek and brook ran full time all year long. The evergreen tree needles glistened in reflected sunlight with lush greenness. It was so had to believe what he had just told me.

    Sadly Tom Roberts died late last year 2017 of Parkinsons. My wife and I took a one day visit to Idyllwild where I once lived this past April 2018. Tom Roberts was both right and wrong. Almost every tree there is dying by the 1000s (he was right) and all the large Sequoias which were to be the ideal replacement are all dying as well (he was sadly wrong). On June 1st a photographer posted a photo on Facebook of the entire valley from an aerial view from a drone flown from the Elementary School sport field. I saw trees clearly dying from ground level, but the aerial photo provided a more complete view of the diasater the area has become. I’d post the photo, but not sure if this blog’s system will publish it. I’ll try separately below.

    Southern California will eventually loose the majority of it’s forests, with only pocket remnants of woodlands remaining providing a historical example of what once was on a grander scale. Even many areas of pure chaparral are in sharp decline.

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