Chin J Plant Ecol ›› 2013, Vol. 37 ›› Issue (9): 820-829.DOI: 10.3724/SP.J.1258.2013.00086

• Research Articles • Previous Articles     Next Articles

Strobili and seed characteristics of Tsuga dumosa and its relationship with environmental factors

LI Li1,2,*(), YANG Jia-Ni3, CUI Kai1, R. Talbot TROTTER4,5, LI Zheng-Hong1, LI Gen-Qian2, LIAO Sheng-Xi1   

  1. 1Research Institute of Resource Insects, Chinese Academy of Forestry, Kunming 650224, China
    2College of Forestry, Southwest Forestry University, Kunming 650224, China
    3Science Experimental Class of Liang Xi in 2010, Beijing Forestry University, Beijing 100083, China
    4Northern Research Station, USDA Forest Service, CT 06514 USA
    5School of Forestry and Environmental Studies, Yale University, CT 06511, USA
  • Received:2012-12-26 Accepted:2013-05-22 Online:2013-12-26 Published:2013-09-02
  • Contact: LI Li

Abstract:

Aims In this paper, we studied the timing and environmental factors associated with the production of male and female strobili (cones) of Tsuga dumosa using eight populations of reproductive age.
Methods We measured the growth of 24 reproductive plants, and quantified the production of male and female cones at multiple canopy heights and directions using the standard branch method.
Important findings The ratio of female to male cones was 1:2, and only 28% female cones developed seeds. Plants with a 7 cm diameter at breast height (DBH) (about 25 years old) begin producing cones first, while plants with DBH between 25 and 30 cm produced the highest abundance of male and female cones. A plant with a 89 cm DBH (about 200 years old) produced cones latest. There were obvious differences in the distribution of male and female cones at different canopy heights and orientations. Correlation analyses show that there was a significant positive correlation between DBH and cone (male and female) quantity (p < 0.01), and a significant positive correlation between DBH and the size of canopy. There was a negative correlation between canopy density and cone quantity, height, and DBH. The seed yield was significantly negative correlation. Analysis using principal components indicated temperature, water, and light exposure were the main factors affecting cone production. These factors caused population decline in the ratio between female and male cones towards male-biased, and seed bearing period is long and seed bearing way is not economic. Thus, weather conditions aggravated population decline. Artificial regeneration, establishing a seed orchard, and improving the quality of seeds are significant factors in the improvement of seed quality and population restoration.

Key words: environmental factor, female cone, male cone, population restoration, strobili, Tsuga dumosa