**5. Conclusions**

Collectively, our study found that (i) rather high mass loss and carbon release in decomposition *A. faxoniana* litter was observed in high elevations of the subalpine forest subjected to low temperatures in the non-growing seasons and (ii) there were stimulative effects of forest gaps on litter decomposition in early decomposition, especially in the non-growing seasons, driven by fewer freeze–thaw cycles when compared to the closed canopy, which diminished at the end of the experiment though. Overall, these findings provide new insights into how opening gaps as a main regeneration method at different elevations would induce changes in carbon cycling in subalpine forests. We therefore sugges<sup>t</sup> that future models of litter decomposition may benefit from including forest gaps and emphasizing non-growing seasons to make more accurate predictions. However, the biological mechanisms involved in the decomposition processes may need further investigation, such as considering the microbial and faunal strategy reactions to the forest gap formation.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/f13081201/s1, Table S1: Geographic information of forest gaps.

**Author Contributions:** Conceptualization, H.L. (Han Li), Q.W. and L.Z.; software, T.D., Y.C. and J.Y.; validation, T.D., Y.C., Y.Z. and Q.D.; data curation, H.L. (Han Li); writing—original draft preparation, H.L. (Han Li) and Q.W.; writing—review and editing, H.L. (Han Li), L.Z. and Q.W.; visualization, H.L. (Han Li), Y.Y. and L.Z.; funding acquisition, H.L. (Han Li), L.Z. and Q.W. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (31901295, 32071747 and 32001165), the Program of Sichuan Applied Basic Research Foundation (2022NSFSC0997, 2022NSFSC0083, 2022NSFSC0087 and 2022NSFSC1173), the Open Fund of Ecological Security and Protection Key Laboratory of Sichuan Province Mianyang Normal University (ESP1902), and Research Fund of Mianyang Normal University (QD2020A18).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Written informed consent has been obtained from the patient to publish this paper.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** We are grateful to the Long-term Research Station of Alpine Forest Ecosystems and the Collaborative Innovation Center of Ecological Security in the Upper Reaches of the Yangtze River.

**Conflicts of Interest:** The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.
