The Relationship Between The Climate And Radial Growth Of The Trees Commonly Used For Restoration In Shandong Province

Applying Vegetation ecology theory to reconstruct forest ecosystem is a new focus of restoration ecology, which emphasizes reconstruction of the native forest with the native trees to restore local forest ecosystem. Therefore, the native trees become the aim of ecological restoration as well as the study object of developing key techniques. Thorough study on the growth traits should be done. The growth especially radial growth of trees has great relations to site conditions and climate changes. Base on the growth variance of tree ring width, we can get some information of the annual growth of the trees and the annual climatic changes in their locations. The effects of the future climatic changes on tree growth and forest structure and function can be predicted, which can provide a credible evidence for ecological restoration measures. In this article three important north species are selected, Robinia psendoacacia L. (black locust) , Pinus densiflora Sieb. et Zucc. (red pine) and Quercus acutissima Carr.(sawtooth oak) to study the relationships between climatic changes and tree radial growth. Black locust, as a perfect hybrid species and a pioneer species in restoring vegetation, is very valuable in restoring vegetation and ecological construction in temperate zone of China In the drought and semi-drought areas, such as Loess Plateau, applying black locust has made better progress. And the largest and broadest broadleaf tree in Shandong province is black locust. Red pine, as the native conifer, has the largest afforestation areas in Shandong province. Some previous studies show that red pine can provide foundation and create conditions for invading and growing of other zonal deciduous broadleaf trees, which is significant for constructing restoring red pines scientifically and restoring deciduous broadleaf trees. Sawtooth oak, as the native deciduous broadleaf tree, its growth, reproduction and distribution accommodate to local environment such as climate and soil conditions. The relationship between tree radial growth and climatic factors of black locust, red pine and sawtooth oak are investigated in this study, which can provide the foundation for ecological restoration from physiological ecology of Shandong province and north China. There is great theoretic value and practical value of artificial afforestation, forest tending and succession in this study.Considering geographical meaning and developing conditions of three species, Laiwu Fanggan (LF ), Zaozhuang Baodugu (ZB ), Dongying Xianhe (DX), Qingdao Laoshan (QL), Dezhou Linyi (DL) and Heze Caoxian (HC) are chosen as sampling plots. We carry out the fieldwork basing on ITRDB. The result indicates that MS is high enough. The MS of black locusts, red pines and sawtooth Oak are respectively from 0.25 to 0.5, 0.2 to 0.3 and 0.25 to 0.3, which shows that the growth of the three species are limited by climatic factors. We choose exponential function to simulate growth trend of three species and get the RWI. Monthly mean temperature and monthly precipitation of current growth season (Apr, May, Jun., Jul., Aug., Sep., Oct.) , out of growth season (Nov., Dec, Jan., Feb., Mar.) , and previous growth season (Apr., May, Jun., Jul., Aug., Sep., Oct.) are selected as climatic factors to process correlation analysis between climatic factors and RWI.Correlation analyses of black locusts in six locations indicate that the radial growth is mostly limited by precipitation in previous winter, precipitation and temperature in current spring and temperature of Jul. in LF. In QL it is mostly controlled by temperature and precipitation in current spring and precipitation of Oct.. In DX it is limited by temperature in current spring and precipitation of previous autumn and Sep.. In DL it is effected mostly by temperature of previous May and current Mar. and precipitation of Oct.. It is controlled by temperature of previous winter, temperature and precipitation of Jul. in HC. Also it is affected mostly by temperature of previous winter and current summer. Therefore, the growth of black locust is mostly limited by temperature in its prophase and midseason of growth season. After peak precipitation in summer, the positive needs of the precipitation for growth show obviously. And for the Lagging effect of temperature and precipitation, the temperature and precipitation in previous autumn and winter influence greatly on the growth of black locust.Correlation analyses of red pines in LF and QL indicate that precipitation of February, temperature and precipitation of Oct. have prominent effect on the radial growth in LF, and in QL the growth is mostly limited by temperature of Feb., Mar., Apr., May and Sep.. As a species fond of light, red pine can be accelerated because rising temperature at the end of growing season with precipitation increasing could strengthen photosynthesis in LF. But excessive precipitation can affect photosynthesis leading to the reduction of the growth. In QL low temperature in spring can be satisfied with the growth. On the contrary rising temperature may aggravate evaporation so as to restrain the growth.Correlation analyses of sawtooth oak in LF and ZB indicate that the radial growth is controlled mostly by the precipitation of previous spring, temperature and precipitation of previous autumn and winter, precipitation of May and Jun. in LF. In ZB the growth is effected obviously by temperature of previous Jun., temperature and precipitation of previous autumn and winter, temperature of Jan., Feb., Sep. and Oct.. It shows that the rich precipitation can reduce the limitation on the growth in ZB, which make the temperature effect more obviously. Because the precipitation in LF is far lower than that in ZB, it becomes the primary limiting factor on the growth in LF with the case of temperature being nearly in both two locations.The Stepwise Multiple Regression is applied to describe the relation between the radial growth and environmental factors. The results show that the variance explanation ratio is much higher in each equation and F test is prominent. Moreover, the Ridge Regression Analysis also is used to build the equation to get better results.Based on the results, the climatic limiting factors are shown and the relationships between the radial growth of three species and the climatic factors are quantitatively described in this study, which can provide scientific foundation for vegetation ecological restoration and provide supplement for the quantitative and modeling studies in ecological restoration, and it is valuable in theory and practice.