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How Much Carbon Do Different Forests Store?

A detailed look at the carbon storage capacities of forest types, how age and management matter, and their crucial climate role.

By Sneha Tete, Integrated MA, Certified Relationship Coach

Created on Sep 27, 2025

A detailed look at the carbon storage capacities of forest types, how age and management matter, and their crucial climate role.

Forests stand as one of our planet’s major tools in the fight against climate change, functioning both as significant carbon reservoirs and as active carbon sinks. But not all forests are alike in their capacity to store or sequester carbon, and understanding these differences can unlock new strategies for climate mitigation and land stewardship.

What Is Forest Carbon Storage?

When we talk about carbon storage in forests, we refer to the total amount of carbon held within the entire forest ecosystem. This storage occurs in several components:

LIVING TREES: Carbon is found in the trunks, branches, leaves, and roots—a result of photosynthesis, where trees convert carbon dioxide into sugars and ultimately build biomass.
DEAD PLANT MATERIAL: Leaves, branches, and trunks that fall to the forest floor contribute carbon-rich litter.
SOILS: Over time, accumulated plant material breaks down and a significant portion of that carbon becomes stably stored in forest soils.

Every forest is a carbon bank, but the amount stored and the rate at which it sequesters new carbon depends on a complex web of factors.

How Forests Capture and Store Carbon

All trees remove carbon dioxide (CO₂) from the air through photosynthesis. The carbon is distributed across their tissues, from root to bud. Over time, much of the carbon is fixed in woody material—making up to 50% of a tree’s dry mass.

But trees are not the full story. Forest soils lock away immense stores of carbon. In temperate and boreal forests in particular, centuries of leaf litter and woody debris slowly convert to stable organic matter, creating thick layers of soil carbon. Tropical forests, with faster decomposition, generally store less carbon in soil and more in vegetation. The interplay between aboveground and belowground pools is essential in any forest carbon accounting.

Young vs. Old-Growth Forests: Carbon Storage and Sequestration

The debate over whether young or old forests are “better” carbon sinks is complex. Here are the key distinctions:

Forest Type	Carbon Storage (Total Stock)	Carbon Sequestration Rate (Annual Change)
Young Forests (0-70 years)	Low	High (rapid growth phase)
Mature/Old-Growth Forests (>100 years)	Very high	Moderate/Low (slower net growth)

Young forests absorb carbon quickly as they regrow after disturbance—this is the rapid “interest accrual” phase of a carbon bank. However, in the years immediately following a major disruption (like clearcutting), the forest system may actually emit more carbon than it absorbs due to active decomposition and respiration, until leaf area recovers.

Old-growth forests store enormous amounts of carbon in their standing timber and undisturbed soils. Their annual rate of sequestration is slower, but the sheer volume of stored carbon (“capital”) is much higher.

Key Factors That Shape Forest Carbon Storage

New scientific research has revealed that the controls on forest carbon storage are nuanced. It’s not simply the age of the forest, but a complex set of biological and ecological processes, including:

Forest Structure: The arrangement of canopy layers and leaf area determine how much light is intercepted and how much photosynthesis can occur.
Tree, Plant, and Fungal Composition: Species diversity, especially the balance of fast- and slow-growing plants and the presence of mycorrhizal fungi, affect both biomass accumulation and organic matter formation in soil.
Soil Nutrients: Particularly soil nitrogen, which can limit tree growth and microbial activity.

Disturbances—whether natural (fire, pests, wind) or human-caused (logging, land clearing)—impact all these factors and can either release or lock in more carbon over the short or long term.

Comparing Forest Carbon Stocks by Region and Type

Globally, forests are immensely variable in their storage capacities. Here are rough comparative figures for different types:

Tropical Rainforests: Among the world’s densest carbon stores, with high biomass above ground; soils are thinner, but total ecosystem carbon can top 250-300 metric tons per hectare (or more) in undisturbed stands.
Boreal (Northern) Forests: Store less aboveground biomass but far more carbon in thick organic soils and permafrost; total ecosystem storage often in the range of 150-250 metric tons per hectare.
Temperate Forests: A middle ground; have a balance of aboveground and soil carbon, typically 100-200 metric tons per hectare in mature stands.

Example Table: Estimated Carbon Stocks in Major Forest Biomes

Biome	Aboveground Carbon (t/ha)	Soil Carbon (t/ha)	Total (t/ha)
Tropical Rainforest	120-200	80-100	200-300+
Boreal Forest	40-60	100-200	140-250+
Temperate Forest	60-100	40-80	100-180

These are approximate values; actual carbon stored can vary widely by site, disturbance history, and forest composition.

The Critical Role of Forest Soil Carbon

While tree trunks are the most visible part of a forest’s carbon store, soils can hold just as much—or more—carbon than all the forest’s living vegetation combined. Decaying roots, woody debris, and centuries of leaf litter gradually build a reservoir sometimes referred to as ‘legacy carbon.’ This pool is resistant to rapid change and can buffer carbon losses in times of disturbance.

However, soil carbon is also vulnerable. Land use changes, intensive harvesting, or fire can release large quantities of stored soil carbon to the atmosphere.

Disturbance, Management, and Carbon Balance

Forest carbon storage is dynamic. Natural cycles of disturbance and recovery—and human activities—have a dramatic effect on the quantity and longevity of stored carbon. Key points include:

Clearcutting and Replanting: Following harvesting, forests often become net carbon emitters for a decade or more until regrowth absorbs enough carbon to offset decomposition and soil respiration.
Old-Growth Conservation: Protecting undisturbed, mature forests is the most effective strategy for maintaining long-term carbon storage; losses from disturbance take many decades—or centuries—to recover.
Management Practices: Practices such as “retention forestry” (leaving some old trees or debris), extended harvest rotations, and minimizing soil disturbance can all increase the amount of carbon stored while balancing timber production.
Wood Products and Substitution: While carbon can be stored long-term in durable wood products, emissions from logging operations, transportation, and wood processing must be factored into the net climate benefit.

Why Protecting Forest Carbon Matters for Climate

Forests absorb roughly 2.6 billion metric tons of CO₂ per year, offsetting nearly a quarter of annual anthropogenic emissions. The carbon stored in old, wild forests is particularly significant—these reserves are, on human timescales, practically irreplaceable. Ensuring these carbon stocks remain intact is one of the most cost-effective and immediate steps in avoiding catastrophic climate warming.

However, the opportunity comes with complexities:

Protecting forest carbon means defending against deforestation, degradation, and conversion to other land uses.
Natural disturbances (fires, pests, windstorms) will continue to cycle carbon, but managed forests can be more resilient with science-based strategies.
Forestry must weigh the needs of carbon, biodiversity, timber, and communities in an integrated approach.

Frequently Asked Questions (FAQs)

Q: How does a tree remove carbon from the atmosphere?

A: Through photosynthesis, trees absorb CO₂ from the atmosphere, incorporate the carbon into sugars, and use this for building their tissues, locking carbon away for decades or centuries.

Q: Which forest type stores the most carbon?

A: Old-growth tropical rainforests have the highest carbon stocks overall, storing significant carbon both above and below ground. Boreal forests store more in soils, while temperate forests are intermediate.

Q: Do young or old forests sequester more carbon each year?

A: Young forests sequester carbon at a higher annual rate due to rapid growth, but old forests store much more total carbon and continue to accumulate it over centuries.

Q: What happens to carbon when forests are logged?

A: Logging releases stored carbon through decomposition of harvest residue, soil disturbance, and the manufacture of wood products. Some carbon remains in wood products, but the ecosystem may not regain lost carbon for many decades.

Q: Can managed forests help with climate change?

A: Yes—especially with improved practices such as retention forestry, longer harvest cycles, and soil protection. But conserving old, undisturbed forests remains unmatched for preserving irreplaceable carbon stocks.

Key Takeaways

Forests store carbon in living trees, dead material, and soils. The balance changes by forest type and management history.
Old-growth forests hold the largest long-term carbon reserves, even if their annual carbon uptake is less than fast-growing young forests.
Soil carbon is a major—sometimes overlooked—component of total carbon stocks.
Forest age is less important than structure, composition, and management in determining overall carbon storage.
Forest conservation, smart management, and restoration are all vital for both mitigating climate change and sustaining ecosystem health.