Table 2. Regional proportions of international research papers related to forest roads in each research area

The 1st research area 1)		The 2nd research area 2)		The 3rd research area 3)		The 4th research area 4)
Study country	Proportion (%)	Study country	Proportion (%)	Study country	Proportion (%)	Study country	Proportion (%)
USA	19	USA	18	China	25	China	22
China	13	China	16	USA	13	USA	13
Canada	8	Canada	5	India	6	India	6
Brazil	7	Brazil	5	Canada	4	Iran	6
India	4	India	4	Iran	4	Canada	4
Australia	3	Poland	4	Brazil	3	Brazil	4
Poland	3	Iran	3	Turkiye	3	Turkiye	3
Germany	3	Germany	3	Poland	2	Australia	2
United Kingdom	2	Australia	3	Australia	2	Poland	2
Iran	2	Turkiye	2	South Korea	2	Germany	2
Spain	2	Italy	2	Germany	2	Italy	2
Italy	2	Japan	2	Spain	2	South Korea	2
Japan	2	United Kingdom	2	Italy	2	Japan	2
France	2	Spain	2	United Kingdom	2	Spain	2
Mexico	2	Finland	2	Japan	1	United Kingdom	2
Turkiye	1	Sweden	2	Finland	1	France	1
South Korea	1	Russia	1	France	1	Sweden	1
Sweden	1	South Korea	1	Sweden	1	Finland	1
Russia	1	France	1	Russia	1	Mexico	1
Finland	1	Mexico	1	Mexico	1	Russia	1
Etc	21	Etc	21	Etc	22	Etc	22
Total	100	Total	100	Total	100	Total	100

The 1st research area: Impacts of forest road-induced habitat fragmentation on wildlife and landscape connectivity.
The 2nd research area: Soil and hydrological environmental impacts of forest road-based operations.
The 3rd research area: Forest road detection, classification, and vehicle operation safety analysis using machine learning and remote sensing technologies.
The 4th research area: Landslide susceptibility assessment and hazard mapping in areas adjacent to forest roads.