Abstract
The present study evaluated the influence of delayed soil thawing on the growth and frost hardiness of Pinus sylvestris var. mongolica saplings between September 2011 and August 2012 in Northern China (41°35′N, 116°32′E). The saplings were randomly divided into three treatments: control, snow removal, and snow removal + insulation. The control saplings were grown under natural conditions. Snow cover was removed from the saplings in the snow removal treatment. For the snow removal + insulation treatment, snow cover was removed and soil surface was covered with a layer of hay (15 cm). The bud break, current-year shoot elongation and diameter as well as current-year needle elongation were measured and compared among the three treatments. The frost hardiness of previous-year stems and needles was assessed using the electrical impedance spectroscopy method. The saplings in the snow removal + insulation treatment exhibited delayed bud break, needle and shoot growth, as well as cessation of needle and shoot growth compared to the other treatments. In contrast, the growth of shoots and needles was generally higher in the snow removal treatment. A linear relationship was observed between plant growth, especially needle elongation, and temperature sum at soil depth of 20 cm. During dehardening, there were no differences in frost hardiness for both stems and needles among the treatments. In conclusion, snow removal + insulation delayed growth, whereas snow removal accelerated the growth. The frost hardiness of saplings during dehardening did not differ among treatments significantly. The possible reduction of snow cover and increase of soil freezing under warming climate would not have negative impacts on saplings in terms of frost hardiness during dehardening. Nevertheless, increased soil freezing would have unfavorable influences in terms of shoot and needle growth.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
