From July 9 to 16, 2026, the Million Tree Project (MTP) conducted its summer forest survey in Inner Mongolia. Over the course of one week, three volunteers joined MTP staff in surveying four plots of middle-aged forests planted between 2010 and 2012 in Tongliao. Together, we measured about 400 trees in 10 sample sites, collected 30 tree cores and prepared 60 plant specimens.
Volunteers conducting on-site forest surveys. Photo by Kai Wang
The team’s primary task was to measure tree growth, including tree height, diameter at breast height (DBH), basal diameter, and crown width to evaluate tree growth status. Years of continuous monitoring show that these indicators have become increasingly stable, suggesting that the forests have entered a mature stage. The accumulation of fallen leaves and other organic matter has also significantly improved the soil conditions.
Volunteers measuring the tree height. Photo by Jiayuan Guo
Volunteers measuring the crown width. Photo by Jiayuan Guo
Layers of fallen leaves on the forest floor. Photo by Jiayuan Guo
Unlike previous years, this year’s survey schedule was significantly affected by unusual weather conditions associated with climate change. The hot, dry conditions experienced by volunteers last year were replaced by persistent rainfall throughout this year’s survey period. During the rainy days, the team shifted their work indoors, preparing plant specimens and polishing tree cores.
Waterlogged forest roads, Photo by Jiayuan Guo
Polishing tree cores. Photo by Jiawen Song
Plant specimen. Photo by Jiawen Song
Fortunately, the rain cleared and the sun came out on the final day. We extend our heartful thanks to all of our volunteers for their dedication and hard work! We hope the cool summer days spent in Inner Mongolia will remain a cherished memory for everyone who took part.
Group photo. Photo by Fia Long