“The best time to plant a tree was 20 years ago.
The second best time is now.”
– Chinese Proverb
Today, people worldwide are working on developing technologies and engineering solutions to climate change by reducing the amount of carbon dioxide (CO₂) and other man-made greenhouse gases in our atmosphere. The scale of this challenge is so vast and complicated that it will likely involve many different approaches to solve it. Of all the methods we know of, the most efficient and cost-effective is - trees. In fact, by managing trees and forests more intensively, we will not only help reduce the impacts of climate change but can also improve wildlife habitats, as well as the overall health of local economies and communities. We also see great opportunities for wood technologies such as mass, cross-laminated timber products that sequester CO₂ rather than materials well-known for generating CO₂, such as concrete and steel.
JLC has been managing forests daily now for three generations. We have been involved with many different landowners and management approaches on countless timberland tracts throughout Northwest Washington and beyond. Over that time, we've gained a lot of insights about what works best and experienced firsthand the impacts of climate change. We are now applying that knowledge to improve forest health while maximizing harvests and improving ecosystems more sustainably.
When discussing climate change, the essential element carbon is often mistaken for carbon dioxide and vice versa. Carbon (often abbreviated with the chemical symbol "C") is Earth's sixth most abundant element. Carbon is essential to life as it is found in all living beings and, at room temperature, is a solid and can also be found in various other forms such as graphite and diamond. Carbon dioxide (CO₂) is the chemical compound of two oxygen atoms and one carbon atom. At room temperature, it is gaseous and is a vital gas for life in the atmosphere since it plays a significant role in photosynthesis. However, the CO₂ that humans release is the leading greenhouse gas (GHG) causing problematic climate change.
How Much Carbon Is In Carbon Dioxide?
When it comes to climate science and GHGs, the focus of those conversations tends to shift back and forth between carbon and carbon dioxide. This often leads to confusion and/or errors because there’s a big difference between the two. Simply put, carbon dioxide by weight is 27.27 percent carbon and 72.73 percent oxygen.
Composition of Carbon Dioxide
These proportions work out to a ratio of 3 parts carbon for every 11 parts oxygen (3:11), which equates to;
One Ton Of Carbon per 3.67 tons of carbon dioxide
Carbon Dioxide Absorption via Photosynthesis
Plants use energy from light to convert water and carbon dioxide into sugar and oxygen in the process known as photosynthesis. Chlorophyll, the green pigment in leaves, absorbs sunlight and uses the energy to convert six molecules of carbon dioxide (6CO₂) and six molecules of water (6H₂O) into one molecule of sugar and six molecules of oxygen. The scientific formula for photosynthesis is written as follows:
6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
This process is how plants help regulate the amount of carbon dioxide in the atmosphere by breaking the bonds between the carbon and oxygen atoms. Plants use the resulting sugar (C₆H₁₂O₆) to grow, converting most of it to cellulose (C₆H₁₀O₅), forming its cell walls, and releasing six molecules of oxygen (6O₂) back into the atmosphere.
Photosynthesis is how plants use sunlight, water, and carbon dioxide to create oxygen and the sugars it uses to form their physical structure.
How Much Carbon Is In Trees?
Live trees are typically about half water and half chemical elements. Subtracting the water, we're left with the pure elemental composition of trees, which is approximately 50 percent carbon. The remaining elements include oxygen, hydrogen, nitrogen, and smaller amounts of calcium, potassium, sodium, magnesium, iron, and manganese.
Elements that make up a tree by dry weight: 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, 1% mineral matter
Using the C-to-CO₂ ratio mentioned above, climate scientists calculate that One Ton Of Trees (Minus The Water Inside) Equals 1.835 tons of Carbon Dioxide Absorbed from the atmosphere.
Because JLC works with living and freshly cut trees, all the trees we deal with are "wet ." That said, here's a simple rule-of-thumb we use for estimating the carbon content of trees containing water which, varies somewhat by species and season:
One Ton of Live Tree ≈ One Ton of CO₂ Captured
Carbon Absorption and Forest Age
Young forests are more effective at removing carbon from the atmosphere than older forests for a variety of factors, including;
Younger trees/forests have higher growth rates than older trees/forests.
Younger forests contain much greater numbers of trees and understory flora than older forests.
Older forests contain many large trees which are more susceptible to losses due to storms, drought, or lightning.
Older trees are more likely to cycle carbon through the soil into the atmosphere than use it to grow.
More significantly, many recent studies, including our own, found that once a forest's age reaches 50-100 years, its high rate of CO₂ sequestration begins to slow and eventually stops. At this point, the forest becomes carbon neutral, meaning it has reached its maximum carbon sync capacity, and net CO₂ uptake ceases. This is because as the forest's dead organic matter decays into the soil, it emits as much CO₂ into the atmosphere as the forest can absorb.
The following graph from JLC's documentation of the tens of thousands of acres we've managed supports these observations, showing peak carbon dioxide absorption occurs between 25-60 years and then quickly tapering off until the forest approaches carbon neutrality by the time it is 150 years old.
Carbon Dioxide Absorption By Forest Age
Young forests are more efficient at removing carbon from the atmosphere than older forests.
There is growing evidence that warming temperatures may lead forests to become carbon neutral at earlier ages, making young forests an even more critical element in carbon sequestration and mitigating climate change.
Managing Forests for Optimum Carbon Sequestration
The graph below is a comparison of how much carbon an acre of forestland can capture over time, based on three different management approaches:
Tree Planting Followed By 60-Year Harvest Cycle Using Intensive Thinning.
Tree Planting Followed By 60-Year Harvest Cycle With No Thinning.
Tree Planting Followed By Indefinite Growth / No Harvest
Over the long term, planting and harvesting forests can remove far more CO₂ out of the atmosphere than unmanaged forestlands.
Managing Forests for Optimum Carbon Sequestration Is Also Good Business
The graph below compares how much timber revenue an acre of forestland can generate over time, based on the same three different management approaches noted above.
Over the long term, planting and harvesting forests can generate far more revenue than unmanaged forestlands.
One Stand - Three Approaches
Recently, JLC had the good fortune of obtaining reliable historical documentation involving forestland in Kitsap County, Washington. Following a clearcut in 1958 by Crown Zellerbach Corp., the tract was replanted with Coastal Western Hemlock in 1961. For reasons unknown to us, we discovered that an area of it that was still standing in 2012 had been managed with three different thinning approaches;
Type 0 - Zero Thinning Entries
Type 1 - One Thinning Entry
Type 2 - Two Thinning Entries
The three stands had a similar NE aspect with no more than 50' elevation change difference.
Overhead view of the Hemlock stands under different thinning practices.
ZERO THINNING ENTRIES
Click Images to Enlarge
Self Thinning | No Pre-Commercial Thin, No Commercial Thin
364 Logs/Acre | Avg. Log 101 BF | Net 36.7 MBF/Acre
ONE THINNING ENTRY
Click Images to Enlarge
Pre-Commercial Thin Only | No Commercial Thin
287 Logs/Acre | Avg. Log 117 BF | Net 33.4 MBF/Acre
TWO THINNING ENTRIES
Click Images to Enlarge
Pre-Commercial Thin + Commercial Thin
365 logs/Acre | Avg. Log 139 BF | Net 50.6 MBF/Acre
Outcome Comparison
BOARD FEET YIELDS BY MANAGEMENT PRACTICE
The chart above shows the stand, which was thinned twice (PCT, CMT), produced 51.4% more marketable timber than the stand with one thinning entry, and 39.7% more marketable timber than the stand that received no thinning entries. These statistics are consistent with results we've seen over the decades on forest lands JLC has managed.
NET HARVEST VALUE BY THINNING TYPE
The chart above shows the stand, which was thinned twice (PCT, CMT), produced 75.7% more marketable timber than the stand with no thinning entries and 52.9% more than the stand, which received one pre-commercial thinning entry. These statistics are consistent with results we've seen over the decades on forest lands JLC has managed.
Tree Diameter and Timber Value
As noted in the photos above, thinning practices significantly impact tree diameter. Removing small and diseased trees reduces competition for sunlight, water, and nutrients among the remaining trees, allowing them to grow faster and straighter. As tree diameter (DBH) increased in the examples above, their value increased correspondingly with their diameter:
Small Diameter = Low-value "Chip-n-Saw" logs used for small dimensional lumber and pulpwood logs for paper products and fuels
Medium Diameter = Mid-value saw logs used for large dimensional lumber and peeler logs for plywood.
Large Diameter = Premium, high-value pole logs which can dramatically increase in value with an additional diameter
By providing a reliable, renewable, and climate-positive source of fiber, managed forests can significantly reduce greenhouse gas emissions and play a vital role in the global transition to a sustainable, bio-based economy. Intensifying tree farm production will also help shift logging away from established natural forests, preserving the carbon syncs and "old-forest" ecosystems they provide.
And it is not just while trees are growing that they can contribute to climate change mitigation. Timber can already replace the use of energy-intensive construction materials like concrete and steel in many applications. Emerging new technologies also hold much promise for tree fiber as being a substitute for most fossil fuel products in the not-too-distant future. While much more work is needed from researchers, policymakers, and private businesses, it is already clear that increased forest production will be an essential element in overcoming climate change. In the meantime, we will be taking advantage of every opportunity we can to put our knowledge and resources to work on realizing the full-potential benefits from the woodlands we manage.
Because the time to plant more trees is now.
Information Sources
World's biggest terrestrial carbon sinks are found in young forests
https://www.birmingham.ac.uk/news/2019/worlds-biggest-terrestrial-carbon-sinks-are-found-in-young-forestsWhy do carbon dioxide emissions weigh more than the original fuel?
https://www.eia.gov/tools/faqs/faq.php?id=82&t=11Forest Management for Carbon Benefits
https://www.fs.usda.gov/ccrc/topics/forest-mgmt-carbon-benefitsMethods for calculating forest ecosystem and harvested carbon with standard estimates for forest types of the United States
https://www.fs.usda.gov/treesearch/pubs/22954What Percentage of the Mass of a Tree is Water?
https://web.extension.illinois.edu/askextension/thisQuestion.cfm?ThreadID=19549&catID=192&AskSiteID=87Does the Age of a Tree Effect Carbon Storage?
https://icp.giss.nasa.gov/research/ppa/2001/anwar/Forest carbon sink neutralized by pervasive growth-lifespan trade-offs
https://www.nature.com/articles/s41467-020-17966-zOld-growth forest carbon sinks overestimated
https://www.nature.com/articles/s41586-021-03266-zCarbon sequestration: Managing forests in uncertain times
https://www.nature.com/articles/506153aLimits to growth of forest biomass carbon sink under climate change
https://www.nature.com/articles/s41467-018-05132-5.epdfComplex forest dynamics indicate potential for slowing carbon accumulation in the southeastern United States
https://www.nature.com/articles/srep08002Forest Carbon from Young vs. Old Forests
https://www.ncasi.org/wp-content/uploads/2021/01/NCASI22_Forest_Carbon_YoungVsOld_print.pdfAn incredible technology for reducing carbon dioxide: planting trees
https://forestsolutions.panda.org/insights/an-incredible-technology-for-reducing-carbon-dioxide-planting-treesRole of forest regrowth in global carbon sink dynamics
https://www.pnas.org/doi/full/10.1073/pnas.1810512116Tree planting has the potential to increase carbon sequestration capacity of forests in the United States
https://www.pnas.org/doi/10.1073/pnas.2010840117Forest Finance 8: To Cut or Not Cut- Deciding When to Harvest Timber
https://extension.psu.edu/forest-finance-8-to-cut-or-not-cut-deciding-when-to-harvest-timberWhy New Forests Are Better At Sequestering Carbon Than Old Ones
https://psmag.com/environment/young-trees-suck-up-more-carbon-than-old-onesAvailability of nitrogen to plants is declining as climate warms
https://www.sciencedaily.com/releases/2018/10/181022135722.htmDon't look to mature forests to soak up carbon dioxide emissions
https://www.sciencedaily.com/releases/2020/04/200408113300.htmNew documentation: Old-growth forest carbon sinks overestimated
https://www.sciencedaily.com/releases/2021/03/210325150055.htmHow Is Carbon Dioxide Absorbed During Photosynthesis?
https://sciencing.com/carbon-dioxide-absorbed-during-photosynthesis-3196.htmlAre young trees or old forests more important for slowing climate change?
https://theconversation.com/are-young-trees-or-old-forests-more-important-for-slowing-climate-change-139813Forest Carbon FAQs
https://www.fs.usda.gov/sites/default/files/Forest-Carbon-FAQs.pdfForests through the Ages: the Importance of Young Forests
https://www.nrcs.usda.gov/wps/portal/nrcs/blogdetail/nrcsblog/home/?cid=NRCSEPRD1179414Young Forests Can Benefit Wildlife
https://www.srs.fs.usda.gov/compass/2014/07/03/young-forests-can-benefit-wildlife/