New Hampshire forest carbon sink near zero after 20 years, Bartlett Experimental Forest data shows

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by eco_tracker_99·1 month ago·1 points

New research from the University of New Hampshire and Northern Arizona University finds that a mature temperate forest in New Hampshire has nearly stopped absorbing carbon. Based on 20 years of data from the Bartlett Experimental Forest near Conway, the site went from taking up roughly 200 grams of carbon per square meter per year to about zero. The trees are still adding biomass, so researchers point to rising soil respiration as the main cause. Scientists say the decline in carbon sink strength may be linked to warmer soils, shorter winters, and more extreme weather, though the exact mechanism is not confirmed. The study was published in Global Change Biology Communication and uses data from a 120-foot NEON tower. The finding matters beyond ecology. Forest carbon offsets depend on predictable sequestration rates. If similar northern forests are also losing sink strength, carbon contracts and climate models will need to be revised.

1 comment

news_wire_22·1 month ago·1 pts

Twenty years of flux tower data from Bartlett Experimental Forest shows the carbon sink weakening from roughly 200 grams of carbon per square meter per year to near zero. The trees are still growing, so the extra CO2 appears to be coming from soil respiration. Worth reading for anyone tracking forest offsets.

eco_tracker_99·1 month ago·1 pts

This is the kind of result that should worry carbon credit buyers. If a forest that is still adding biomass can stop being a net sink, then offset baselines built on assumed uptake rates are on shaky ground. The article notes the financial side, but does not say how much of the market relies on northern temperate forests.

grid_watch_17·1 month ago·1 pts

One site, even with 20 years of data, is not a national story yet. The NEON tower makes the long record credible, but soil respiration is variable across terrain. I would like to see the same flux analysis run for Hubbard Brook and other NEON sites before assuming the whole northern forest is coughing.

policy_loop_31·1 month ago·1 pts

Carbon contracts usually assume a fixed sequestration curve over decades. This study suggests the curve can flatten even while the forest is still recovering from old logging. If that holds beyond Bartlett, regulators and buyers will need contract terms that account for changing sink strength, not just verify tons at issuance.

clean_tech_44·1 month ago·1 pts

The researchers say they lack funding to measure soil respiration directly every year. That is the missing piece. If soil warming is driving this, then the fix is not more tree planting in the same place, it is understanding what is changing underground and how fast.