| Forest ecology system of Changbai Mountain, belonging Northeast China Transect (NECT), is most typical vegetation with vertical distribution and images a vegetation distribution along level, but there is black in systematical research from whole altitude so far. Although B. ermanii is a sub-alpine transition belt from forest to alpine tundra and has higher study value ecologically, little work has been done. Especially under the effect of global climate change, plants in above line of forest are how to respond and acclimate to heterogeneous environments, and how to adjust to challenge climatic changes physiologically and morphologically, which ecologically offers to a very important significance, and moreover, make for us understanding deeply in the terms of the regeneration of forest, the dynamic of community and the intrinsic drive-mechanism of succession on the individual level. Thus, these are able to base for study systematical for Changbai Mountain. In this dissertation, sub-alpine building population B. ermanii was selected as experimental material and studied in characteristics of morphological and physiological changes along altitude of, including climatic condition, leaf morphological traits and light response and CO2 response of saplings, and quantitative traits of mature, and soil physical-chemic properties and nutrient. The following results could be achieved:1.Climatic index including air temperature, precipitation, wind speed and ultraviolet radiation intensity enhanced gradually along altitude. Although humidity declined within forest, however, it was higher in tundra than that in pure forest of B. ermanii, and it was lower in tundra than that in mixed forest, which was likely to due to greater precipitation and wind speed in tundra. The first ten days of August was the growth season, because in this period the temperature, humidity, wind speed precipitation increased markedly. And wind direction generally was northwest leaning north and northeast leaning north in July, and northwest in August. The soil condition of distribution of B. ermanii generally was acidic. The pH was less than 7.0 and reached minimum at 1800m. Soil water content being related with more precipitation was linear along altitude. Soil density varied congruously with pH, but the pertinence was reverse. Soil organic material content and entire nitrogen content had minimum at 1800m. It was just climatic and soil difference that resulted in a recent distribution partern. 2 . With the altitude, Leaf area decreased and became most thin between altitude 1700m—1900m; Chlorophyll was opposite to the changes of leaf nitrogen with a minimum between altitude 1700m～1900m, which suggested B. ermanii invested more nitrogen to chlorophyll in this altitude (NChl); The variation of carotenoid accorded with antioxidant material Pro, APX, DS whereas, countered oppositely with MDA, one of main products resulted from activated oxygen, which illustrated that B. ermanii evolved effectively antioxidant system when inhibition became bad and bad with increased altitude. Higher antioxidant and physiological plasticity value showed B. ermanii depended on more physiological than morphological to adjust to acclimation.3.Maximum net photosynthetic rate Pmax, apparent quanta yield AQY, carboxylation efficiency CE, photosynthetic energy transformation efficiencyδ, maximum carboxylation rate Vcmax and maximum electronic transfer Jmax of saplings of B. ermanii increased and then decreased with altitude, exhibiting maximum in 1700m～1900m, but light compensation point LCP and CO2 compensation point CCP were reverse, and obtained minimum in the same altitude range. It could be concluded that origin of B. ermanii was from1700m—1900m altitude with most active photosynthesis, and developed adown or upwards. Dark respiration rate Rd, light respiration rate Rday and solar energy use efficiency SUE were positively linear with increased altitude, and maximum photochemistry efficiency Fv/Fm was higher than 0.8, which suggested photosynthesis of B. ermanii was not suffered from stress among its distribution range, however, the stress was stronger and stronger with increased altitude and thus led to current distribution pattern which will continue varying under the effect of global change.4.With the altitudinal gradient increasing, while density of B. ermanii generally increased and height and breast diameter decreased, they all showed a fluctuation in 1800m around that the density increased abruptly and then declined and increased again, height was no change, and the breast diameter fell in a great degree from 1800m. This altitude thus could be regarded as a watershed of distribution which even belonged to distribution range of highest activity of photo-physiology of B. ermanii, so the altitude 1800m could be cognized as its original point. Compared with B. ermanii in low altitude, although Picea jezoensis could obtain more light through lower branch height and greater crown, less height and breast diameter showed hard to acclimate the high latitude environment. At the same time, low altitude reflected higher dependent on light for B. ermanii. Compared with B. ermanii in high altitude, the greater breast diameter and height of Larix olgensis showed its stronger flexibility, but its survival exchanged with high death rate. Among distribution range of B. ermanii, the herbage Rhododendron aureum accompanied all along and the change of growth height was consistent with B. ermanii, which could better served as indication plant for B. ermanii.
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