Letter: What is happening in Tahoe right now is bigger than a debate about one chemical

What is happening in Tahoe right now is bigger than a debate about one chemical, one project, or one agency decision.

It is really a collision of grief, distrust, climate change, science, public lands, and the uncomfortable reality that many of the systems we once relied upon no longer feel stable.

The Caldor Fire changed people. It changed landscapes that many of us love deeply. Entire forests that once felt permanent suddenly looked fragile. Trails, watersheds, wildlife habitat, and places connected to memory and identity were transformed in ways that still feel difficult to process. For many people in Tahoe, these forests are not abstract policy discussions. They are where we ride bikes, hike, ski, fish, raise our children, and reconnect with ourselves.

Now communities are being asked to navigate another emotionally charged question: how do we restore forests at the scale climate change now demands?

That question becomes even harder when the conversation includes glyphosate.

For many people, glyphosate is not just a forestry tool. It represents decades of distrust toward corporations, regulatory agencies, and scientific institutions that too often appeared influenced by money and political pressure. Roundup lawsuits, cancer stories, and investigative reporting about Monsanto’s influence over research and regulatory messaging deeply shaped public perception. Many community members no longer automatically trust assurances that something is “safe when used properly.”

And honestly, that distrust did not emerge out of nowhere.

At the same time, foresters and restoration scientists are trying to respond to a rapidly changing ecological reality. California’s forests are no longer behaving the way they historically did. Fires are burning hotter, larger, and more intensely. In some areas, forests are not naturally regenerating because seed sources have been destroyed and aggressive brush species quickly dominate the landscape. Scientists warn that some forests could permanently transition away from conifer ecosystems if restoration efforts fail.

Following the 2021 Caldor Fire, these tensions became especially visible in the Lake Tahoe Basin. According to the U.S. Forest Service Lake Tahoe Basin Management Unit, herbicides are not being proposed as a primary restoration strategy, but rather as a limited and targeted tool that could potentially be used if manual methods fail to support successful reforestation. Current project documents state that herbicides could be used “to aid site preparation before tree planting and to manage competing vegetation after planting when manual treatments are ineffective or expected to be insufficient.” The project also describes “minimal use of herbicides to support reforestation.”

Of the roughly 11,000 acres included in the Basin Project area, use of herbicides may not be used at all in the 2,400 and 3,600 acres proposed for active reforestation. They are proposed for use only where manual treatments are ineffective or expected to be insufficient. Importantly, approximately 16,000 seedlings were recently planted in the Caldor burn area without herbicides at all. However, foresters note that several years after planting, aggressive brush species can overwhelm young conifer seedlings and prevent long-term forest recovery.

That creates another difficult truth: doing nothing also carries consequences.

If forests fail to recover after very large fires, the landscape can shift into a brush-dominated system. These systems are often hotter, drier, and less biodiverse. When young trees are unable to compete with dense brush, forests struggle to regenerate and create the mosaic of vegetation types that supports healthy ecosystems. In contrast, landscapes with a mix of brushlands and forested areas are more biodiverse and more resilient to wildfire and climate change.

Restoration professionals are not imagining these concerns. They are seeing them on the ground across California’s burned landscapes.

Some estimates suggest California now faces millions of acres that will require active reforestation if we want to see forested mosaics return in these areas with restoration costs approaching nearly $1 billion annually. For many scientists and restoration crews, the question is no longer whether intervention is needed, but how restoration can happen responsibly at the scale now required.

This is why the current debate feels so emotionally exhausting for many people. Both sides are speaking from legitimate fears.

Some people fear chemical exposure, long-term ecological contamination, and corporate influence over science.

Others fear losing entire forest ecosystems.

And many people fear both at the same time.

The science itself has also become part of the conflict. In 2015, the International Agency for Research on Cancer classified glyphosate as “probably carcinogenic to humans.” At the same time, the EPA and several international regulatory agencies continue to maintain that glyphosate is unlikely to pose a carcinogenic risk when used according to approved standards. That disagreement has left many community members unsure which institutions they should trust.

Even some forestry professionals acknowledge that questions surrounding long-term exposure thresholds, ecological impacts, and cumulative environmental effects deserve continued scrutiny and updated research.

That nuance often gets lost in public conversations because modern discourse rewards certainty, outrage, and simplified narratives. Social media pushes people toward teams instead of complexity. Yet the reality is that most people involved in this conversation care deeply about Tahoe, public health, and the future of the forest.

There are also broader questions underneath all of this.

Can large-scale forest restoration happen without some chemical intervention?

Should society invest far more heavily in labor-intensive alternatives like manual thinning, grazing programs, volunteer stewardship crews, expanded restoration jobs, and prescribed grazing using goats?

Can we rebuild independent scientific institutions that the public genuinely trusts?

What happens when climate change creates ecological problems so large that none of the available solutions feel entirely good?

These are not easy questions.

And Tahoe is not facing them alone. Communities across the West are struggling with similar tensions as megafires reshape forests faster than public policy, funding systems, and restoration capacity can keep up.

Perhaps the most important thing right now is resisting the urge to reduce the conversation into heroes and villains.

The person worried about glyphosate is not automatically “anti-science.”

The forester worried about failed reforestation is not automatically “pro-chemical.”

Both may be responding to real evidence, lived experience, and legitimate concern.

Public engagement matters deeply here. Environmental review, independent science, transparency, community oversight, and continued pressure to explore lower-impact restoration methods are all essential. Communities should absolutely continue asking hard questions. But those conversations work best when people remain curious enough to acknowledge that the situation itself is extraordinarily complicated.

The future of Tahoe’s forests will likely require multiple approaches: restoration science, public accountability, expanded stewardship, climate adaptation, and perhaps most importantly, a willingness to stay in difficult conversations without immediately turning each other into enemies.

Because ultimately, most people standing on opposite sides of this issue are trying to protect the very same thing:

a living, resilient Tahoe that still feels wild generations from now.

Excerpt from the Caldor Fire Environmental Assessment (EA)

2.1.1.2 Reforestation: Site Preparation, Planting, and Competition Release

Within the Caldor Fire burn area, there are approximately 4,900 acres where the probability of natural forest regeneration is less than 40 percent (Estes and Bovee 2023), these areas are shown as the reforestation layer on MAP 2 – Reforestation Activities. These areas experienced high-severity stand replacing fire that killed existing native seeds, and are located in areas where surviving forest stands, or adjacent unburned forests are not likely to be a seed source for natural regeneration of trees. Of these 4,900 acres, reforestation actions are proposed on between 2,400 and 3,600 acres. Planting locations would be strategically located and prioritize reforestation on north and west facing slopes. Reforestation treatments would include three specific actions: site preparation, tree planting and competition release.

• Site Preparation: To prepare planting sites, shrubs would be removed using mechanical, hand, herbicide treatment or prescribed fire methods to reduce competition and enhance the survival and establishment of newly planted trees. In areas where forest thinning and fuels reduction treatments are conducted, additional site preparation may not be required when planting occurs within a year or two after treatments are completed. Mechanical site preparation could involve mastication of shrubs and felling of standing dead trees prior to planting where equipment access exists. Hand cutting of shrubs and felling of dead trees ahead of planting could occur where equipment access is not possible. Prescribed understory burning could also be used to remove shrubs ahead of planting. Herbicide application may also be used for site preparation ahead of tree planting in combination with other methods or as a stand-alone treatment. Hand grubbing to bare mineral soil of an area approximately 2 ft x 2 ft could occur at the time of planting for each individual tree. This would occur when it is needed to remove any remaining vegetation around the planting site.

• Planting: Nursery-grown locally adapted seedlings would be planted following site preparation activities. Seedlings would be selected from native conifers within the appropriate seed and elevation zones. A variety of native tree species would be planted to promote species diversity, guided by silvicultural objectives. Conifer seedlings would be planted exclusively in upland conifer forests, avoiding riparian and meadow areas and aspen stands. Trees would be planted in combinations of clustered and regularly spaced seedlings that vary with microsite water availability, so that a balance is created between planted tree stands dense enough to outcompete vegetation with minimal intervention. Planting would be primarily conducted by hand crews. Drones may also be utilized to assist with planting. Planting would occur when sites are accessible and have proper soil temperatures and sufficient moisture, generally during late spring/early summer after snow melt or in the fall before snowpack and frozen ground condition occur.

• Competition Release: In the years following planting, shrubs and grasses may compete with tree seedlings. Where the presence of shrubs outcompete and overtop seedlings, a release treatment to reduce competing vegetation may be needed. Where needed, release treatments would generally occur three to five years after planting. Release treatments would be conducted by hand crews using chainsaws and grubbing tools to remove competing vegetation from around seedlings. Prescribed understory burning may also be used, either as a follow up to hand release treatments or as an initial treatment when the risk of mortality to seedlings from prescribed fire actions is low. Herbicides may be used where manual treatment is ineffective or anticipated to be ineffective at control of competing vegetation.

2.1.1.3 Herbicide Treatment

Herbicides may be used to support reforestation objectives. Specifically, herbicides may be used to aid site preparation before tree planting and to manage competing vegetation after planting when manual treatments are ineffective or expected to be insufficient. Between 2,400–3,600 acres are proposed for reforestation; of these acres, use of herbicide would be limited to the areas where tree planting occurs. Not all acres that are planted are anticipated to require use of herbicide.

The goal of herbicide application is to reduce target vegetation to the level needed to achieve silvicultural objectives and reforestation success. Target species are woody shrubs such as western whitethorn (Ceanothus velutinu), Greenleaf manzanita (Arctostaphylos patula) and ceanothus (Ceanothus spp.) that are likely to out compete and overtop tree seedlings. Herbicide applications with possible additives could include the active ingredients glyphosate, triclopyr (amine, ester, and choline formulations), hexazinone, imazapyr, and aminopyralid.  For all treatments, herbicides would be used as part of an integrated approach in conjunction with other release methods. Herbicides would be applied with backpack sprayers as a direct foliar spray¹, or by other low-volume methods such as cut stump, basal bark spray, and thin-line application. These low-risk application techniques target the most competitive plants. There would be no aerial or aquatic application of herbicides. Multiple applications may be required to achieve desired conditions for control of competing vegetation. The initial herbicide treatment would kill competing plants, but the seed bank in the soil is expected to remain viable and additional treatment may be required.  Herbicides would not be applied June 1 to September 30. The herbicide active ingredients proposed for use, along with their proposed application rates are shown in Table 2-1. Herbicide application would comply with product label directions and applicable legal requirements and would not exceed the application rates analyzed described in Table 2-1. In no circumstances would application exceed the maximum rates as allowed by the label.

In all cases of use, the minimum interval between applications as specified by product label direction would be adhered too. All applications would follow Forest Service herbicide guidance (Forest Service Manual 2150 [Forest Service 2013b] and Forest Service Handbooks 2109.14 [Forest Service 2016] and 6709.11 [Forest Service 2018]) including guidelines to minimize human exposure. These guidelines include the use of dyes, signage, personal protective equipment (PPE), and treatment timing. In addition, resource protection measures (RPMs) (refer to Appendix A) would minimize damage to non-target native plants, reduce risk of offsite-drift and buffer application from ephemeral, intermittent and perennial streams and other waterbodies within the Project Area. 

¹ Direct backpack foliar spray consists of a backpack sprayer (a tank) of a diluted herbicide solution used to apply

herbicides to targeted plants. Spray is typically controlled by the applicator using a handheld wand to direct a coarse

spray of herbicides to target vegetation. Directed foliar spray concentrates spray upon the target plant with the intent

of minimizing spray between target plants.

Table 2-1. Description of Chemical active ingredient, Application Rate and Additives Proposed 3

Notes:

1. All herbicides proposed are approved for use by the U.S. Environmental Protection Agency and the California Department of Pesticide Regulation, which is the state agency responsible for regulating pesticides. Human Health and Ecological Risk Assessments (HHERAs) developed by Syracuse Environmental Research Associates (SERA) were used to evaluate the risks associated with each herbicide and inform appropriate protective measures (SERA 2005, 2007, 2011a, 2011b, 2011c).

2. Spot treatments of Aminopyralid may be applied at an equivalent broadcast rate of up to 0.22 lb acid equivalent per acre per year; however, not more than 50 percent of an acre may be treated at that rate.

3. Proposed application rate per acre depends on Triclopyr formula used (amine, ester, or choline formulations).

-Colleen Bye, South Lake Tahoe