Wind disturbance in northern hardwood forests of the US North Central Great Lakes region creates heterogeneously distributed structural attributes such as downed woody debris (DWD) and canopy openings across temporal and spatial scales. The decomposition of DWD contributes to greenhouse gas (GHG) fluxes, provides habitat, and potentially influences soil biogeochemistry. We assessed the effects of DWD addition on soil GHG fluxes in the decade after experimental manipulation of downed woody amounts and canopy openings in a maturing second-growth deciduous forest to (1) determine the spatial relationship between DWD proximity and soil GHG fluxes (CO₂, CH₄, N₂O); (2) evaluate the relationship of decay class, canopy condition and environmental variables to wood decomposition and soil fluxes; and (3) use the fine scale surface patterns to estimate carbon emissions from the ground layer stratum. Our results revealed the shifting influence of individual pieces of DWD on soil microbial activity with advancing wood decay and depending on canopy condition. Modeled daily soil CO₂ fluxes increased near moderately and highly decayed DWD in open canopy compared to control soils but decreased near highly decayed wood in closed canopy. Despite high variability and low CH₄ (mean: − 0.02 ± 0.01 mg m⁻² s⁻¹) and N₂O (mean: − 0.0007 ± 0.0008 mg m⁻² s⁻¹) soil fluxes, higher uptake in closed canopy paralleled the patterns of CO₂ efflux. Our findings indicated that northern hardwood forests have the potential to be important CO₂ and trace gas sinks, especially under intact canopy, but that widespread reductions in DWD in secondary forests of the region likely altered potential GHG soil uptake.

美国中北部五大湖地区北部阔叶林的风扰造成了分布不均的结构属性，例如倒塌的木质碎片 (DWD) 和跨时空尺度的树冠开口。DWD 的分解有助于温室气体 (GHG) 通量，提供栖息地，并可能影响土壤生物地球化学。我们评估了 DWD 添加对土壤 GHG 通量的影响，在对成熟的第二次生长落叶林中的树木倒塌量和冠层开口进行实验操作后的十年中，以 (1) 确定 DWD 接近度与土壤 GHG 通量 (CO ₂ , CH ₄ , N ₂哦); (2) 评价腐烂等级、冠层条件和环境变量与木材分解和土壤通量的关系；(3) 使用精细尺度表面模式估算来自地层的碳排放。我们的结果揭示了随着木材腐烂的推进和冠层条件的不同，单个 DWD 对土壤微生物活动的影响不断变化。与对照土壤相比，开放冠层中模拟的每日土壤 CO ₂通量在接近中等和高度腐烂的 DWD 附近增加，但在封闭冠层中高度腐烂的木材附近减少。尽管高变异性和低 CH ₄（平均值：- 0.02 ± 0.01 mg m ^-2  s ^-1）和 N ₂ O（平均值：- 0.0007 ± 0.0008 mg m ^-2  s^-1 ) 土壤通量，封闭冠层中较高的吸收与 CO ₂流出模式平行。我们的研究结果表明，北部阔叶林有可能成为重要的 CO ₂和微量气体汇，尤其是在完整的树冠下，但该地区次生林 DWD 的广泛减少可能会改变潜在的 GHG 土壤吸收。