Study On Dynamics And Modelling Of Moisture Content Of Ordinary Plants Species Within Growing Period In Maoershan Region

The moisture level of combustibles determines the difficulty of forest burning. Study the change rule of combustible live moisture content, and establish a real-time prediction model to have the important meaning, moisture content of26kinds Main species(eight arbor species,ten shrub species, eight herb species) and meterological variables were measured during growing seasons for two successive years in Maoershan Experimental Forest, Northeast Forestry Univiersity. Analysis was conducted on the dynamics of the moisture contents and evaluate its Combustion characteristics through the classification. Prediction models for these shrub moisture content were established by conducing multiple regression over the obserbed moisture content and environmental factors such as soil moisture, maximum daily temperature, crown drought index, daily mean temperature and cumulative precipitation. The results showed that, moisture content were higher than100%during growing season for all the ten shrubs, and higher than200%within the period from leaf out through leaf falling for Woody plants. In the course of the study of eight arbor species, Prunus maackii and Acer tegmentosum were incombustible during the whole growing period due to extremely high moisture content while the rest six species were combustible only during periods of leafout and leaf falling within the growing season. Moisture content of most of the ten shrubs were significantly correlated with soil moisture content (6out of8species) as well as with canopy drought severity index (CDSI)(7out of8species). Daily maximum temperature, daily mean humidity and cumulative precipitation of multiple-days shows significant correlations with moisture content only for1pecies. Prediction models established using these variables as predictive variables can explain more than30%of moisture content variance for3species with a mean MRE of37.5%and a mean MRE of14.6%, respectively. In the course of the study of eight arbor species, Euonymus verrucosus, Sorbaria sorbifolia, and Ambucus williamsii were incombustible during the whole growing period due to extremely high moisture content while the rest seven species were combustible only during periods of leafout and leaf falling within the growing season.2) Moisture content of most of the ten shrubs were significantly correlated with soil moisture content and daily maximum temperature (7out of10species) as well as with canopy drought severity index (CDSI)(5out10species). Daily mean humidity and cumulative precipitation of multiple-days shows significant correlations with moisture content only for2-4species. Prediction models established using these variables as predictive variables can explain more than35%of moisture content variance for9species with a mean MRE of35.9%and a mean MRE of13.4%, respectively, moisture content were higher than130%during growing season for all the ten shrubs, and higher than200%within the period from leafout through leaf falling for Woody plants. Prediction models established using these variables as predictive variables can explain more than30%of moisture content variance for5species with a mean MRE of92.3%and a mean MRE of13.6%, respectively. In addition, Ordination analysis were made with detrended Canonical Correspondence Analysis (DCCA) to the live moisture content of species. The altitude influenced remarkably the live content moisture and The values of the live content moisture decreased with the increases of altitude.The values of the live content moisture of woody plants with the increases of soil moisture content, The values of the live content moisture of herbaceous plants with the decreases of soil moisture content.The result of classification indicates that The DCCA axes1efficiency of the arbor species,arbor species,herb species was significant, so as the total efficiency.