Patterns Of Net Primary Productivity For Chinese Major Forest Types And Their Mathematical Models

Part of the forest biomass data sets were from my biomass researches in subtropical forests of Guangxi Province four years ago, and also from my additional field works on the ratios of specific leaf area, stem growth rates and live-biomass densities of forests in Changbai Mountain of Jilin Province and Huitong Research Station of Hunan Province in 1995. Other data were gathered and sorted out from the literature in past 20 years over China and from the continuous forest-inventory plots of the forestry departments. These data are included: 668 plots with biomass measurements, 1285 biomass allometric regression equations for 98 tree species or forest types, 4507 continuous forest-inventory plots with measurements of tree height and DBH, 1616 stem analysis trees for 180 tree species. We developed a methodology to link together data from forest inventories and ecological research sites, and provided a large database about leaf area index, live-biomass and NPP over China. According to the characteristics of the geography and monsoon climate in China, the statistic models between the annual mean temperature/precipitation and latitude, longitude and altitude were established separately for eight regions, by use of the data from near 1000 meteorological observation stations. Then the distribution patterns of biological production of Chinese major forest types were analyzed. The main results follow.(1) Establish a series of regression equations for relations of net primary productivity of Chinese major forest types to climate variables. The different combinations of climate factors significantly influence the NPP distribution patterns of the differentforest types. Due to differences of biological and ecological characteristics in the different forest types, the different models of the relationships between NPP and climate factors exist. Different forest types have their different responses to climate conditions within their distribution areas. For the cold temperate Picea-Abies forests, the relationship between the productivity and the mean annual temperature & precipitation is a compound curved surface, generally NPP increases with the increasing of temperature and precipitation, and the increasing rate differs greatly in the different hydro-thermal combinations. For the cold temperate/temperate Larix forests, the productivity increases with the increasing of warm index and precipitation in the way of hyperbolic quadratic surface. For the temperate Pinus tabulaeformis forests, the productivity is positively related to precipitation and negatively related to thermal factors (annual mean temperature , warm index & potential evapotranspiration) , this curved surface is unique. For the mountain temperate pine forests of P. Armandii, P. densata and P. taiwanensis, the productivity increases with the increasing of hydro-thermal factors in the way alike Larix forests. For the subtropical Chinese-fir (Cunninghamia lanceolata) plantations, the relationship between the productivity and the hydro-thermal factors is a parabolic quadratic surface, i.e. there is an optimum requirement of hydro-thermal combination for the growth and distribution of Chinese-fir forests, and under a certain hydro-thermal combination , the maximum productivity exists (function maximum). For P. massoniana forest growing over the eastern subtropical zone, the productivity is related to thermal factors in the way of parabolic quadratic curve, and positively related to precipitation in the way of the natural logarithmic curve, then its curved surface looks like a piece of tile. For the typical deciduous broad-leaved forests in the warm temperate, the productivity is positively linearly related to the moist index in the way of the natural logarithmic curve, but negatively related to the annual mean temperature. The shape of its compound curved surface is similar to that of P. tabulaeformis forests. For the mountain Populus-Betula forests, the productivity is linearly related to the moist index. For the green broad-leaved forest, green-deciduous broad-leaved forest and sclerophyllous broad-leaved forest in the subtropical zone,their productivity increases with the increasing product of temperature multiplyed precipitation in the way of the natural exponential curve, a saturation curve with the maximum of 33.5 t/ha.a. The shape of its compound curved surface is similar to that of the Larix and mountain temperate pine forests.2 Discover that leaf area index of different forest types has different distribution patterns in response to different climate conditions. Leaf area index of Picea-Abies and P. tabulaeformis forests are negatively related to the mean annual temperature in the way of the natural exponential curve. For Chinese-fir and P. massoniana plantations, LAI is related to the thermal factors in the way of the parabolic quadratic curve. For the typical deciduous broad-leaved forests, LAI is positively related to the moist index in the way of the natural logarithmic curve, but negatively linearly related to the mean annual temperature. For Populus-Betula forests, LAI is positively linearly related to the moist index. For the three subtropical broad-leaved forests, LAI is positively related to the annual mean temperature and precipitation in the way of the parabolic quadratic surface. These regular distribution patterns of forest LAI provide a theory for the scaling of the located ecosystem research results and for the developing of the eco-physiological modeling in large scales.3 Estimate the total live-biomass and NPP for Chinese forests based on the statistics from the plot data and the area data of various forest types from the Forestry Ministry in 1989-1993. The total forest area (except economic forests and bamboo forests, and the forests in Taiwan) is 1.0864×10~8 ha, the total live-biomass is 13.7825× 10~91 DM and the total NPP is 1.3089×109 t DM. The total biomass and NPP of Chinese forests respectively make up 0.84% and 1.77% of that of the world forests. The orders in the total biomass of various forest types are as following: green/green-deciduous broad-leaved forests (18.40%) > typical deciduous broad-leaved forests (15.23%) > P. massoniana forests (13.93%)> Picea-Abies forests (12.73%)>Larix forests (9.30%)>mountain Populus-Betula forests (8.71%)> Chinese-fir plantations (5.02%)>P yunnanensis and P. khasya forests (4.09%)> mountain temperate pine forests^ koraiensis forests (2.76%)> sclerophyllous broadleaved forests (2.17%)>.P Tabulaeformis{\.74%)>tropical rain forests and seasonal rain forests and their secondary forests (1.10%) >Cupressus forests (0.95%)> P. sylvestris forests (0.36%) .The orders in the total productivity of various forest types are as following: typical deciduous broad-leaved forests (17.70%) > green/green-deciduous broad-leaved forests (16.58%) > mountain Populus-Betula forests (15.97%) > P. massoniana forests (15.50%)> Chinese-fir plantations(7.67%)>Iam forests (7.56%) > Picea-Abies forests (4.71%)> mountain temperate pine forests (3.36%) > P. yunnanensis and P. khasya forests (3.12%)> P. koraiensis forests (1.93%)>P ta6w/ae/o/7m.s'(1.76%)>sclerophyllous broad-leaved forests (\.56%)>Cupressus forests (1.21%) > tropical rain forests and seasonal rain forests and their secondary forests (1.03%) >P. sylvestris forests (0.34%).4 Draw NPP map of the major vegetation types on the Tibetan Plateau by means of the GIS technique. The scaling from plot to region was preliminarily achieved and the available method and technology may be provided for the mapping of Chinese vegetation productivity distribution.5 Examine and assess whether the famous inter- and intro-national climate productivity models, such as Miami, Montreal and Chikugo, are suitable to Chinese forests. The series of the hydro-thermal optimum models of the productivity for Chinese major forest types are commonly better, other five comprehensive climate productivity models are not commonly suitable to all kinds of forest types.