*3.2. When*

On the one hand, this section is about the year of publication of Historical Ecology articles; on the other hand, it is about the historical periods studied in the research papers.

### 3.2.1. Years of Publication

Figure 1 shows the number of articles published per year, the oldest we found is from 1998 [70]. The year 2010 presented a peak, 2015 reached the highest number of publications, and 2020 had another peak. Even though we include the information of all 118 articles in the whole article, we did not include the year 2021 in Figure 1 because the data is incomplete for this year as our search ended in May 2021. There is a trend of increasing the number of Historical Ecology publications, as shown by the trend line.

**Figure 1.** Year of publication of 115 articles until 2020. There is an increasing trend in the number of publications. For 2021, we found three publications but did not include them here, as the yearly data is incomplete.

### 3.2.2. Historical Periods Studied

Concerning the historical periods investigated, a total of 90% of the articles study the 21st century, whereas 83% study the 20th century, 56% refer to the time before the 16th century, 44% to the 19th century, around 30% consider the 16th, 17th and 18th centuries, and 8% point out different geological eras. We must remember that the articles often refer to various periods.
