Gardens by the Bay How good can a man-made garden be?Come and see why this garden is the most impressive in the world.There are three glass greenhouses:The Flower Dome,the Floral Fantasy,and the Cloud Forest.They are ...Gardens by the Bay How good can a man-made garden be?Come and see why this garden is the most impressive in the world.There are three glass greenhouses:The Flower Dome,the Floral Fantasy,and the Cloud Forest.They are all air-conditioned,and inside where you can see beautiful flowers,ferns,and trees.At Cloud Forest,you can even see an incredible tropical rainforest.After leaving the greenhouses,you will be able to see the Supertree Grove.These towering extraordinary structures stun everyone.It’s a must-see,especially at night when the light show transforms the area into a glowing fairyland.展开更多
Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yal...Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yalu Tsangpo River, Nyang River and Parlung Zangbo River. In this study, with P. densata forest distributed in southeast Tibet as research object, the seed rain, soil seed bank, seed germination and natural regeneration of P. densata were monitored and ana- lyzed by field investigation, located monitoring and indoor experimental analysis. The results showed that the average intensity of the seed rain of P. densata was 249.30±78.42 seeds/m2, in which the intensity of full seeds was 168.09±56.36 seeds/m2, the intensity of seeds damaged by worms was 41.11±20.25 seeds/m2, and the intensity of empty seeds was 40.10±21.04 seeds/m2. The intensity of the seed rain exhibited a single-peak trend of increasing at first and decreasing then over time. The spatial distribution patterns in the whole seed falling process and at different seed falling time all exhibited clumping distribution, and within in certain range, with the distance from the seed tree increasing, the diffusion intensity of the seed rain was weakened, exhibiting approximately normal distribution. In average density of P. densata seeds in the soil seed bank of P. densata was 231 seeds/m2, in which 62.77% of seeds were distributed in the litter layer, and 37.23% of seeds were distributed in the soil layer, and about 8% of seeds were lost during the pro- cess from seed rain to soil seed bank. Field sowing observation showed that the accumulated germination rate curve of P. densata fitted with Logistics equation y= 91.404/（1＋e66194.449）. The height structure, basal diameter structure and age structure of seedlings and young trees of P. densata were all of reverse ＂J＂ type, indicating good natural regeneration of P. densata. This study would provide a science basis for protection and resource management of P. densata, and further enrich the eval- uation content of national ecological safety curtain of the Tibet plateau.展开更多
文摘Gardens by the Bay How good can a man-made garden be?Come and see why this garden is the most impressive in the world.There are three glass greenhouses:The Flower Dome,the Floral Fantasy,and the Cloud Forest.They are all air-conditioned,and inside where you can see beautiful flowers,ferns,and trees.At Cloud Forest,you can even see an incredible tropical rainforest.After leaving the greenhouses,you will be able to see the Supertree Grove.These towering extraordinary structures stun everyone.It’s a must-see,especially at night when the light show transforms the area into a glowing fairyland.
基金Supported by Natural Science Foundation of China(31460200)Natural Science Foundation of Tibet Autonomous Region(2016ZR-15-40)~~
文摘Pinusdensata is one of the main constructive species for coniferous forests in southeast Tibet. P. densata forests are important water conservation forests in the drainage basins of the middle and lower reaches of Yalu Tsangpo River, Nyang River and Parlung Zangbo River. In this study, with P. densata forest distributed in southeast Tibet as research object, the seed rain, soil seed bank, seed germination and natural regeneration of P. densata were monitored and ana- lyzed by field investigation, located monitoring and indoor experimental analysis. The results showed that the average intensity of the seed rain of P. densata was 249.30±78.42 seeds/m2, in which the intensity of full seeds was 168.09±56.36 seeds/m2, the intensity of seeds damaged by worms was 41.11±20.25 seeds/m2, and the intensity of empty seeds was 40.10±21.04 seeds/m2. The intensity of the seed rain exhibited a single-peak trend of increasing at first and decreasing then over time. The spatial distribution patterns in the whole seed falling process and at different seed falling time all exhibited clumping distribution, and within in certain range, with the distance from the seed tree increasing, the diffusion intensity of the seed rain was weakened, exhibiting approximately normal distribution. In average density of P. densata seeds in the soil seed bank of P. densata was 231 seeds/m2, in which 62.77% of seeds were distributed in the litter layer, and 37.23% of seeds were distributed in the soil layer, and about 8% of seeds were lost during the pro- cess from seed rain to soil seed bank. Field sowing observation showed that the accumulated germination rate curve of P. densata fitted with Logistics equation y= 91.404/（1＋e66194.449）. The height structure, basal diameter structure and age structure of seedlings and young trees of P. densata were all of reverse ＂J＂ type, indicating good natural regeneration of P. densata. This study would provide a science basis for protection and resource management of P. densata, and further enrich the eval- uation content of national ecological safety curtain of the Tibet plateau.
