Establishment of health assessment system of Pinus tabulaeformis in Beijing Songshan nature reserve

In order to establish a set of health standard evaluation system for natural Pinus tabulaeformis in Beijing Songshan nature reserve in morphology，we randomly selected 50 strains in the test zone，in health， sub-health， unhealthy ecology index， on the base of observation of its appearance diagnosis index， growth index， studied the relationship between ecological index and morphological index， and then evaluated the health standard of P. tabulaeformis from morphological index system. The results showed that， from the diagnosis of morphological appearance， health P. tabulaeformis had tall and straight trunk， small inclination， good growth， developed crown， green pine needles and less dead branches； sub-health P. tabulaeformis had slightly tilted trunk， well growth， basically developed crown， some yellow pine needles， some dead branches and broken branches； unhealthy P. tabulaeformis had large amplitude tilt of trunk， no obvious growth， sparse canopy， yellow pine needles， many dead branches and broken branches. From the diagnosis of morphological growth index， health P. tabulaeformis had the ratio of leaf biomass and trunk biomass over 60%， retained more 2 years old pine needles，and the length of 2 years old pine needle was more than 8 cm；sub-health P. tabulaeformis had the ratio of leaf biomass and trunk biomass with 50%-60%， retained many 2 years old pine needles，and the length of 2 years old pine needle was 4-8 cm； unhealthy P. tabulaeformis had the ratio of leaf biomass and trunk biomass below 50%， retained less or no 2 years old pine needles， and the length of 2 years old pine needle was below 4 cm.