The growth rate of Dahurian larch was studied in the Dahurian forests on the permafrosts which are located about 340km northeast of Yakutsk.
During summer, the soil thawed to about 60cm-depth in a dense forest. The soil
temperature and the water content at 20cm-depth were recorded at about 5°C and 15% respectively on August 12. Dahurian larch roots expanded widely into the soil around 20cm below the ground surface. Thus, the low soil temperature and the low soil water content are among the most important factors limiting tree species growing in dry and high latitudial permafrost regions.
The maximum width of annual ring of the larch was below 2.5mm in the tree show-ing the best growth, and below 1mm in the oppressed trees. In the Dahurian forests studied, the growth rate of Dahurian larch was much lower than that of Japanese larch, and the full-density curve in the former was much lower than that of the latter. The volume percentage of bark in Dahurian larch stem amounted to about 30%, which was 2.5 times as' great as that of Japanese larch. These results suggest an adaptation of Dahurian larch to drv climates.