A Study on Root Characteristics and Nutrients of Different Aged Larix principis-rupprechtii Mayr.Plantations Genetic diversity of Larix principis-rupprechtii Mayr. seed orchard among generations Effects of high temperature and doubled CO2 on antioxidant enzymes and lipid peroxidation in Larix principis-rupprechtii Mayr seedlings Genetic diversity and population structure of elite Larix principis-rupprechtii Mayr in Beijing