| Loranthus tanakae, a deciduous shrub, belongs to Loranthus, Loranthaceae and mostly colonizes species of the family Fagaceae plants. It is a parasitic plant found on Quercus wutaishanica, which is a dominant and constructive tree species in forests of Mount Ziwuling. In this study, a large amount of Loranthus tanakae were collected from Mount Ziwuling, their distribution, number and age were investigated. Meanwhile, the weight of fruit, leaf and stem of each branch was measured. The survival analysis of Loranthus tanakae in Mount Ziwuling was based on the construction of the age structure, static life table, curves of survival etc., in this paper. Additionally, the biomass allocation and growth rule were revealed through comparing each part of L. tanakae, including its fruits, leaf and stem. The major results were shown as follows:(1) The number of Q. wutaishanica, Pinus tabuliformis, Loranthus tanakae and branch used in this study was 54,15,31 and 237, respectively. Among that,21 Q. wutaishanica were found to be infected by Loranthus tanakae, accounting for 38.9%. However, there was no Pinus tabuliformis infected by Loranthus tanakae.(2) The survival curve of the L. tanakae population in Mount Ziwuling is characterized as the type Deevey II, with a relative stable mortality. The pattern of the disappearance rate curve is similar to that of the morality curve. They both had two peaks, one occured at age 5 and another was at age 10. Fluctuation in the risk rate curve occured at age 6, and the survival curve showed a declined trend while the cumulative morality rate curve increased. The L. tanakae entered the senescence after age 8. According to the analysis on the age composition of the survival curve, the L. tanakae population remained stable in the early and middle stages, but declined in the later stage.(3) The decomposition test shows that the global biomass allocation of L. tanakae is stem>leaf>fruit, whereas the effect of age and height on each part is in this order: fruit>stem>leaf. The growth of L. tanakae is mainly manifested on the stem when it is young. The leaf biomass remains a stable proportion in its whole cycle. Fruits appeare at 2 years and reache to vigorous period during 4-8 years.(4) The number of young individuals (1-5 years) was more than that of mature ones and the maximum life of L. tanakae was 10 years.(5) L. tanakae tends to parasitize on the upper, thick and strong stem of high host plants. Here, the L. tanakae grows well, with a large amount of fruits. In addition, animal behavior may be an important factor which affects the L. tanakae age structure and biomass allocation.(6) The Functional values of survival rate and cumulative mortality rate of L. tanakae population crossed at 3.5 years, and the cross point was 0.5. The ratio of reproductive to vegetative growth was 0～0.3. And the maximum of this ration reached to 0.27 at 6～7 years, which is a turning point for L. tanakae. Before this point, its growth and reproduction are vigorous but declines after this point. |
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