Intra-Annual Xylem Growth of Larix principis-rupprechtii at Its Upper and Lower Distribution Limits on the Luyashan Mountain in North-Central China

Forests

Yuan Jiang¹  Yiping Zhang¹  Yuanyuan Guo¹  Muyi Kang¹  Mingchang Wang¹  Biao Wang¹  Michael C. Stambaugh² 

[1] State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, 19 Xinjiekouwai Street, Haidian District, Beijing 100875, China; E-Mails:State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, 19 Xinjiekouwai Street, Haidian District, Beijing 100875, China;

关键词: treeline;    cell differentiation;    xylogenesis;    elevational gradient;    threshold temperature;   

DOI  :  10.3390/f6113809

来源: mdpi

【 摘 要 】

Altitude-related climatic factors, especially temperature, are important factors that affect tree growth in mountain forest ecosystems. The aims of this study were to estimate the intra-annual radial growth differences of Larix principis-rupprechtii (L. principis-rupprechtii) between its upper and lower distribution limits, at 2740 and 2040 m a.s.l, respectively. Dynamics of xylem growth were observed by collecting microcore samples weekly during the 2011 growth season. The result indicated that different strategies were adopted at the two selected sites. Trees at the upper distribution limit adopted an “intensive strategy” with higher maximum growth rates (0.69 cell·day⁻¹) within a shorter duration of 95 days, producing 21 new tracheids. By contrast, trees at the lower distribution limit exhibited an “extensive strategy” with lower maximum growth rates (0.53 cell·day⁻¹) over a longer duration of 135 days, producing 50 tracheids. The soil temperature was probably the main factor limiting the onset of cambial activity for L. principis-rupprechtii, its daily mean thresholds for onset were 0 °C and 1.4 °C at the upper and lower distribution limits, respectively. These results indicate that L. principis-rupprechtii is able to adjust its xylem growth according to environmental conditions.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.