Effects Of Climate Change On Tree-ring Width And Vessel Features In Betula Platyphylla

Tree growth are affected by the genetic characteristics itself and the environmental conditions, especially closely related with climatic conditions. Many researches on tree-growth response to the climate change have been reported recently. But researches about response of Betula platyphylla growth to climate change(mainly the temperature and rainfall)are rarely reported. With Betula platyphylla as the research object, the response of tree-ring width, vessel diameter and vessel density in Betula platyphylla to climate change was studied by simple correlation analysis and response analysis methods.The results were as following:(1) The average temperature of April had a negative effect on the tree-ring width in the breast and crown base, and the rainfall of April had a positive effect on the tree-ring’s width in the breast. The rainfall of the May and the previous year’s April had a big effect on the vessel diameter in the breast. The average temperature and rainfall of September had a significant effect on the vessel diameter in the stump.(2) With the increase of the stem, the response of tree-ring width, vessel diameter and vessel cell density to climate change had a increasing tendency.(3) The vessel diameter had the most severe response than tree-ring’s width and vessel cell density to the climate changes.The result showed that the influence of temperature on the Betula platyphylla’s radial growth is slightly greater than rainfal. The higher temperatures can easily lead to the vessel’s number and size become smaller, and then to form a narrow tree-ring. But the rainball will increase the size and number of vessel, but then lead to increase the tree-ring’s width. Vessel diameter has a strongest response to climate change than tree-ring’s width and vessel cell density in Betula platyphylla.The response strength decrease following the decreasing of stem which keeps consistent with auxin concentration in the cambium. Suggesting the impact of climate change on the growth of white Betula platyphylla is due to climate change altering auxin concentration. However, it remains to be further research.