What If We Can Have Our Cake and Eat It Too?

“Climate-smart” timber management: longer rotations and conserving older existing stands is a win for the planet without compromising wood production

 

by Paula Swedeen, Ph.D. CNW Policy Director

Northwest forests have a crucial role to play in trapping and storing carbon from the atmosphere to help reduce climate change. We’ve known for a long time that our beautiful old-growth forests store massive amounts of carbon.  But new modeling by Conservation Northwest, in partnership with Washington Environmental Council and developed by Resilient Forestry, offers good news for bringing working state and private forests in western Washington into the climate fight. There is a feasible pathway to increase carbon sequestration and storage on these lands so they can significantly aid in the struggle to maintain a livable planet and society.  

Conservation Northwest has long advocated for the Washington Department of Natural Resources (DNR) to manage its westside forest lands for better carbon storage and biodiversity outcomes. That work included our filings for the landmark case on which the Supreme Court recently ruled, Conservation Northwest et al. v Franz, and an op-ed in the Seattle Times. We also believe that with the right financial incentives, such changes can and should happen on some westside private timberlands. Research shows that longer rotations combined with conservation of older existing stands result in higher overall carbon storage in forest ecosystems than does logging on 30 or 40-year rotations across the land base.

This type of “climate-smart” management also provides the opportunity for more structural complexity and therefore higher biological diversity than does managing for simply-structured plantations. 

The pushback from industrial timber proponents has long been, “It’s too hard to make the transition from where things are now to where we want to be.” In other words, they fear that the transition between the two management regimes would involve a large drop in timber volume that would cause mill closures, put people out of work, and displace the harvest elsewhere. Difficulties with a transition to longer rotations have also been explored in this series by Kate Anderson of Sightline Institute.  

Our modeling shows this fear may be unfounded, which presents a great opportunity. Conservation Northwest and Washington Environmental Council worked with Resilient Forestry to develop an optimization model to explore how a transition might occur (methods can be found here). We tested multiple scenarios to see if there are pathways to longer rotations that don’t involve drastic dips in timber volume production. Our values inform a desire that such a transition maintains milling infrastructure and forestry-related jobs. Political reality also dictates that it must if it is to have any chance of being implemented.

Our results show it is possible to achieve good outcomes for everyone who depends on our forests. This means there is no need to pit climate against the economy or environmentalists against wood products workers. 

State Lands 

Our modeling shows that under some scenarios, the portion of DNR lands in western Washington that is actively managed for timber (about 700,000 acres, the remaining 600,000 remains unharvested or lightly thinned for restoration for endangered species) can be raised from an area-weighted average stand age of 48 years to 80 years within a 70-year transition period. In doing so, these forests absorb and hold an additional 32 million metric tons of CO₂ than at the start and raise by 57.4 million metric tons the combined CO₂ stored in both the forest and resulting wood products. (Note to forest carbon nerds: We used wood products carbon accounting methods from this 2019 paper which corrects common overestimates of carbon stored in wood products over time.)  

This increase would draw down the equivalent CO₂ emissions from 12 million cars, or 177,000 cars per year operating for over 70 years.  

It is important to note that wood products do not store carbon indefinitely and by 120 years (see Figure 2 in this paper) the wood products’ carbon pool would be smaller. On the other hand, forests remain as long-lived carbon storage reservoirs because the forest is a living ecosystem, actively sequestering carbon and maintaining it in soils and vegetation for centuries. 

In the meantime, timber production would gradually increase even as the forest stores more carbon. Our model shows volume increasing from 440 million board feet per year to 600 million board feet per year after 70 years, and without a decline at any point in the transition.   

You read that right: No real decrease from the current annual volume from the 2014-2024 Sustainable Harvest Calculation to get to the multiple benefits we want. Benefits include more CO₂ drawdown into the forest, older structurally complex forests (better biodiversity outcomes), and more, not less, timber volume and therefore likely more jobs.

We acknowledge this is a model, but if these results hold up, it looks like we can have our cake and eat it, too!  

How can this be? The increased thinning that we model produces the continued timber volume while the forest area as a whole grows older. And that thinning, if done correctly, increases stand complexity and biodiversity. It also allows thinned stands to grow older by leaving the overall stand intact and letting the oldest trees get bigger. And when the final harvest is done on stands with ages more in the 70 to 80-year range compared to 40-50 years old, there is more volume per acre available to harvest.  

The model parameters can be adjusted to harvest more or less aggressively to get either more volume or more carbon in the forest within the bounds of increased rotation age. We were looking for scenarios that hit a sweet spot of increasing carbon in the forest over time and that harvested timber on a relatively even flow – i.e., no big dips in harvest and no declines in forest carbon (which leads to increased CO₂ emissions). Scenarios that maximized timber volume decreased carbon stocks over the later years while scenarios that maximized carbon storage in the forest produced lower timber volume than current DNR harvest levels, likely just displacing that harvest elsewhere.

Another important outcome of our “Goldilocks” scenario is less clear-cutting overall. Under DNR’s current west-side sustainable harvest calculation plan, they clear-cut a little over 11,000 acres per year and thin about 1,600 acres. The scenarios we modeled would flip that script and reduce clearcutting to about 3,000 acres per year in the early years and gradually increase it to a little over 6,000 acres per year by the end of the 70-year simulation. Our west-side managed forests are great at sucking up CO₂ if we just allow them to grow older before harvest. And while our model did not account for this, less clear-cutting means less forest disturbance, which leads to less breakdown of wood and organic matter on the forest floor, and therefore lower CO₂ emissions.  

In contrast, if this same land base was managed on a 40-year rotation without thinning, the average forest age would decline from 48 to 46, and forest CO₂ declines by over 9 million metric tons by the end of our 70-year modeling period. The combined forest and wood product change in CO₂ storage is 20 additional million metric tons, all coming from wood products, compared with the 57.4 million metric ton CO₂ gain in the long rotation scenario.

The regime we modeled would also protect the remaining mature forest. The harvest of older forests, where they are uncommon on the landscape, results in net emissions that are not made up for decades and are never made up through managing the resulting plantations on a 40-year rotation. We, therefore, constrained harvest in the early years to nothing older than 80 years. As the average stand age increases over the landscape to 80 years, harvesting stands at that age no longer increase net emissions.    

We acknowledge our model does a lot of thinning. It thins every stand that is ready to thin, which is not standard practice. Is it really feasible to make this big management change? We think so. Switching to a thinning-heavy harvest approach would require more people, more money, and a change in mindset. Making this possible would likely require an upfront investment in DNR’s workforce and investments in forestry workforce development.  While our model did not allow for fine-tuning the amount of thinning, in the real world, it could be dialed down somewhat and still allow for maintenance in volume harvested over time, and result in more carbon stored in the forest.   

After the Supreme Court’s ruling in Conservation Northwest et al. v. Franz, DNR has the legal flexibility to make such changes, as doing so would benefit both the public and the named beneficiaries. DNR would need the legislature’s support to fund the ramp-up and maintenance of staff. Given all the benefits, including increased rural employment, wouldn’t it be worth it? 

Private Lands Results

It is not only public lands where these results can be found. We ran the same scenario on the equivalent acreage of private land with a higher harvest level at the start to reflect the difference between industrial and DNR management practices. We got similarly impressive results: Forest stand age increases from 30 to 75 years, CO₂ storage in the forest increases by 37 million metric tons, and total forest plus wood products increases by 62 million metric tons. Timber harvest increases gradually from 520 million board feet per year to 630 million board feet per year. Note that the gains are larger on private lands due to higher productivity on average of industrial lands than DNR lands. These acres are also starting at a lower average age so have more room to improve.  

The economic and legal context on private lands is obviously different. There are no laws that would compel any existing private landowner to make these kinds of management changes. However, some non-forest companies’ increased interest in mitigating their emissions could drive investment in industrial timberlands as they come up for sale. Or investor pressure to meet environmental and social governance goals (ESG) could factor in. If a landowner had climate mitigation as an overriding goal rather than maximizing financial returns to investors, switching to this management approach would pay off in multiple benefits, and easily pay for itself through commercial volume.    

“Leakage” is one of the major concerns we hear from entities interested in managing forests for carbon sequestration. This refers to the displacement of emissions associated with harvest to someplace else negating any real gains. These results demonstrate that no harvest displacement is necessary to achieve meaningful carbon gains. Social impact investors can also contribute to local economies by maintaining timber flow to mills and employing more people in the woods, not to mention the value of healthier streams and more abundant fish and wildlife. 

Conclusion

While the state’s legally binding emission reduction targets and the Climate Commitment Act aim to get us to net zero emissions by 2050, there will still be excess levels of CO₂ in the atmosphere causing damages. If we lengthened rotations to 80 years on both state and private lands, Washington could significantly contribute to drawing down excess CO₂ concentrations in the atmosphere. Doing so on 1.4 million combined state and private acres as we modeled would draw down an additional 120 million metric tons of CO₂ stored in the forest and in wood products. That’s 120 percent of our total 2018 emissions and more than double what our emissions are required to be by 2030. We can achieve all this while not having to choose between jobs and the environment.   

What are our next steps? We will engage with DNR, the Board of Natural Resources, Trust beneficiaries, and private landowners to discuss our results. We also want to test our model with more precise underlying inventory data on state lands (we used publicly available Forest Inventory and Analysis Data) to see if our results hold up. We will also take a deeper dive into forest management’s economics and labor requirements based on thinning versus clear-cutting in a future blog post.  

We hope our modeling effort moves the discussion significantly along from the realms of academic debate on the one hand and fear of change in forest harvest-dependent communities on the other, to a potentially shared vision of forest management that increases our chances of surviving climate change and leaves nobody behind.