As an ideal timber and landscaping tree species, Betula costata has great ecological and economic value. At present, the resources of B. costata are scarce, so artificial cultivation should be strengthened to meet the resource reserve. B. costata is not suitable for sowing propagation due to seed characteristics of short-life, dormancy, low maturity and difficult collection, therefore, cutting becomes one of the suitable means. The purpose of the study was to explore the rooting effect of tender cutting of B. costata under different treatments and provide theoretical and technical support for its rapid propagation and application.

According to L18(3⁷) orthogonal experimental design, we measured the rooting indicators, including rooting rate, the longest root length, number of adventitious roots and root effect indexes under the different factors (substrate type, sampling site, hormone type, hormone concentration and treatment time) by using the 2-3-year-old shoots as the cutting materials.

The cutting substrate had a significant effect on rooting rate, longest root length, adventitious root number and root effect indexes. The rooting rate, number of adventitious roots, longest root length and root effect index were significantly affected by the sampling site. The kinds of hormones showed significant effects on rooting rate and average root length, but had no significant effects on other indexes. Hormone concentration and treatment time had no significant effect on each index.

We found that treatment 16 [Substrate 3 (vermiculite + fine river sand + peat soil) + the upper cuttings + 500 mg·L^-1 ABT + 30 min soak] was the best, with a rooting rate of 38.89%.