**5. Conclusions**

Based on the historical map of 1944 and Landsat remote sensing satellite images, this paper quantitatively analyzed the spatial distribution and change in forests from 1944 to 2013, aiming at the evolution law of long-time series spatial distribution characteristics of forest cover in karst areas and the events and factors that may affect the forest changes in the unsustainable stage. The main conclusions are as follows: (1) the forest area in the study area showed a trend of decreasing at first and then increasing. From 1944 to 1986, the deterioration phase of forest area decreased, and from 1986 to 2013, the restoration

phase of forest gradually increased. (2) The forest with an altitude of 2000~2500 m changes most frequently in the damage recovery stage, and the forest with a slope of 6~15◦ faces the greatest risk of damage. (3) The changing characteristics of forests with different soil types and lithology in different stages show that it is more difficult to restore forests in karst areas after they are destroyed. To sum up, the use of historical maps can better solve the temporal and spatial evolution of long-time series of forest cover before there is no remote sensing image due to the limitation of satellite launch time. At the same time, it is necessary to pay attention to forest protection in the subsequent social and economic development of karst areas, to avoid damage and increase the cost of rehabilitation.

**Author Contributions:** Conceptualization, X.B.; methodology, Y.T.; software, L.Q.; validation, Y.L. and Y.X.; formal analysis, J.W. and L.W.; investigation, C.L., C.R. and S.Z.; resources, F.L. and G.L.; data curation, X.B.; writing—original draft preparation, F.C.; supervision, X.B.; project administration, X.B.; funding acquisition, X.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research work was supported jointly by the Western Light Cross-team Program of Chinese Academy of Sciences (No. xbzg-zdsys-202101), National Natural Science Foundation of China (No. 42077455 & No.42167032), Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB40000000 & No. XDA23060100), Guizhou Provincial Science and Technology Projects (No. 2022-198), High-level innovative talents in Guizhou Province (No. GCC [2022]015-1 & No. 2016-5648), Guizhou Provincial 2020 Science and Technology Subsidies (No. GZ2020SIG), Opening Fund of the State Key Laboratory of Environmental Geochemistry (No. SKLEG2022206 & No. SKLEG2022208).

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

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Acknowledgments:** We would like to thank all the authors and reviewers for their great guidance and help in writing this manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

