Geographical Variation Of Functional Traits Of Main Tree Species In Northeast China

Functional traits of plants are the liriks to study the changes of plants and environment which have been developed in recent years.They play a decisive role in the distribution and range of species in certain habitats.Community ecology based on functional traits of plants has been widely applied.Plant functional traits refer to a series of plant attributes that have potentially significant impacts on plant colonization,survival,growth and death.These attributes can individually or jointly indicate the response of ecosystems to environmental changes,and have a strong impact on ecosystem processes.Studying the relationship between plant functional traits and environment can provide theoretical basis for us to study functional traits and ecosystem functions,community species coexistence mechanism,and predict the impact of global climate change on vegetation distribution.In this paper,the intraspecific variability of tree height,specific leaf area and wood density and the trade-off among the traits of shade-intolerant tree species and shade-tolerant tree species with significant differences in representative ecological strategies in northeastern China were studied,and the geographic gradient pattern of plant functional traits and its causes were discussed in combination with climatic factors in order to predict species coping cycle.The adaptation potential of environmental change provides scientific basis.The main results and conclusions are as follows:1.The results showed that there was no significant correlation between specific;eaf area and tree height,specific leaf area and wood density,tree height and wood density(P>0.05),and the determination coefficient R2 of all standardized principal axis regression analysis was lower than 0.04.Therefore,there is no trade-off between specific leaf area,wood density and tree height.2.The height of different tree species varies with latitude,longitude and elevation gradient.The tree height of Betula platyphylla,Fraxinus mandshurica and Acer Maple was negatively correlated with longitude,and the tree height decreased with the increase of longitude.The tree height of Populus davidiana,Fraxinus mandshurica and Acer Maple was negatively correlated with latitude,and the tree height decreased with the increase of latitude.The tree height of Betula platyphylla and Fraxinus mandshurica was positively correlated with altitude,and the tree height increased with altitude.3.The relationship between specific leaf area and longitude,latitude and altitude gradient varies with tree species.The specific leaf area of Betula platyphylla,Populus davidiana,Fraxinus mandshurica and Acer palmatum had significant linear correlation with longitude.The specific Ieaf area of Betula platyphylla and Populus davidiana decreased with the increase of longitude,while the specific leaf area of Fraxinus mandshurica and Acer palmatum increased with the increase of longitode.The specific leaf area of Betula platyphylla,Populus davidiana and Fraxinus mandshurica was positively correlated with latitude,and the specific leaf area increased with latitude.The specific leaf area of seven typical tree species did not change significantly at elevation gradient.4.There was a significant linear positive correlation between wood density and longitude,and the value of wood density increased with the increase of longitude.There was a significant linear negative correlation between wood density and latitude of Quercus mongolica,and the value of wood density decreased with the increase of latitude.The wood density of all tree species showed no obvious change trend on the elevation gradient.5.The specific leaf area of Betula platyphylla was negatively correlated with annual precipitation,while that of Quercus mongolica,Poplar and Fraxinus mandshurica was negatively correlated with annual mean temperature.The tree height of Betula platyphylla was negatively correlated with the average annual temperature,while that of Betula platyphylla,Populus davidiana,Quercus mongolica,Fraxinus mandshurica and Pinus koraiensis was positively correlated with the annual precipitation.The wood density of Quercus mongolica was positively correlated with the average annual temperature,while that of Acer Maple was negatively correlated with the average annual temperature.6.Intraspecific variation eoefficient of specific leaf area of photophilie tree species ranged from 38.98%to 51.08%,which was significantly higher than that of other two traits,while the variation coefficient of tree height of shade-tolerant tree species ranged from 38.62%to 48.09%was also significantly higher than that of other two traits.The intraspecific variation rate of wood density was the lowest among the three traits.The main conclusions are as follows:1.There is no significant correlation between the functional traits of all 7 tree species in this paper.The potential reason may be that the scale of this study is large,the distribution of the sample is wide,and the niche difference is large,which leads to no trade-off between the traits on a latger scale.2.The variation of tree height,specific leaf area and wood density along the geographic gradient of different tree species varies with tree species and characteristics,so the main climatic driving factors are also different.3.Annual precipitation is the dominant factor affecting the tree height of the main tree species in northeastern China,while the change of specific leaf area of the main tree species in this area is mainly affected by the average annual temperature.4.The difference of intraspecific variability of tree height and specific leaf area between light-loving and shade-tolerant tree species reflects the difference of their light adaptation strategies,whieh is of great significance to the study of species distribution pattern on a large scale.5.Wood density is highly conservative in the study area.There is no significant change in the geographic gradient,and the intraspecific variation of species is smaller than the other two traits.The results of this study can provide theoretical basis for predicting the adaptive potential of species to environmental change and its environmental driving mechanism,and have practical guiding significance for the construction and future development of natural forest areas in China.