The age structure of a Lurix gmelini population in the northern part of the Great Xingan mountains consists of one to several age waves. Three types (one-, two- and multi-generation populations) , plusing eleven subty...The age structure of a Lurix gmelini population in the northern part of the Great Xingan mountains consists of one to several age waves. Three types (one-, two- and multi-generation populations) , plusing eleven subtypes of age structure can be classified. As the basic unit of the age structure, age waves show an apparent β distribution in the range from 20 to 60 years. The interval between the starting points of two adjacent age waves is more than 100 years. Natural disturbances,especially forest fires that occurred in this area have had an important effect on the age structure. Most of the age waves resulted from forest fires, but the effect of windfall on the age structure also can be revealed through the analysis of young age waves. Generally, high intensity and low frequency fires are usually followed by one-generation populations, while low intensity and high frequency fires by two- or multi-generation populations.展开更多
Larix tannin-phenol-formaldehyde (TPF) adhesive, having 60% by weight of phenol bcing replaced, was evaluated for its utilization in plywood. The kinetic characteristic of the TPF resin was investigated through differ...Larix tannin-phenol-formaldehyde (TPF) adhesive, having 60% by weight of phenol bcing replaced, was evaluated for its utilization in plywood. The kinetic characteristic of the TPF resin was investigated through differential scanning calorimetry (DSC) and the results obtained from the DSC scans show that the resin has a little bit different thermochemical behavior from that of phenol-formaldehyde (PF) resin. Two kinds of plywood panels wcre produced using the TPF adhesive in laboratory. The desired test results met the Chinese GB 9846-88 and ZB B70006-88, respectively, and the long assembly time of TPF resin in preparing plywood can be improved by mixing with the filler.All the properties of plywoods bonded with the TPF adhesive were compared with those obtaincd with synthetic PF adhesive.展开更多
Fifty-three larch interspecific hybrid clones(Larix kaempferi × L.gmelini) and their parent clones were used for growth curve analysis of height variations.The growth curves of the 55 clones were 'S'-shap...Fifty-three larch interspecific hybrid clones(Larix kaempferi × L.gmelini) and their parent clones were used for growth curve analysis of height variations.The growth curves of the 55 clones were 'S'-shaped and 36 exhibited similar curves as the male parent.The coefficients of the logistic models were higher than 0.943,indicating that our results were effective in the simulation of the growth curves.ANOVA analysis showed significant differences in height of different clones (P\0.01).Average date of maximum height growth was Day 173,and average duration of rapid growth lasted for 50 days.Annual average increase in height was 9.7cm d^(-1) and daily average increase was 0.2 cm.The ratio of GR to the total annual increase in height ranged from 51.2 to 68.8%,with the average being 59.8%.There was a positive correlation between k values and plant heights which benefited from the evaluation of early plant height.There was also a positive correlation between GR(growth stage),GD(plant height) and annual increase in height.These results are informative to the evaluation of the elite clone selection and provide a theoretical basis for breeding and management.展开更多
物候是气候变化敏感指标,是陆地生态系统模型的关键参数。目前关于气候变化对物候影响的研究较多,但关于多环境因子交互作用对秋季物候影响的研究尚不充分,制约着物候变化机制的认知与模型发展。以兴安落叶松幼苗叶黄期为研究对象,采用...物候是气候变化敏感指标,是陆地生态系统模型的关键参数。目前关于气候变化对物候影响的研究较多,但关于多环境因子交互作用对秋季物候影响的研究尚不充分,制约着物候变化机制的认知与模型发展。以兴安落叶松幼苗叶黄期为研究对象,采用控制实验研究叶黄期对升温、光周期和氮添加变化及其交互作用的响应。结果表明:(1)升温对兴安落叶松幼苗叶黄期的影响较显著,升温使叶黄始期和叶黄普期显著提前,完全变色期不显著推迟;(2)光周期变化对叶黄期的影响极显著,光周期延长使叶黄始期和叶黄普期显著提前,完全变色期显著推迟;(3)叶黄期与氮添加量相关性不显著;(4)升温、光周期和氮添加变化双因子交互作用对叶黄始期和叶黄普期的影响均极显著且均存在极值,但对完全变色期的影响均不显著:升温与光周期延长交互作用使叶黄始期和叶黄普期提前,且在升温1.5℃、光周期14h时最显著;光周期延长与氮添加交互作用使叶黄始期和叶黄普期提前,且在施低氮(5g N m^(-2) a^(-1))、光周期10h时最显著;升温与氮添加交互作用使叶黄始期和叶黄普期提前,且在施高氮(20g N m^(-2) a^(-1))、升温1.5℃时最显著;(5)升温、光周期和氮添加变化交互作用对叶黄始期和叶黄普期影响极显著,对完全变色期的影响不显著。这表明,升温、光周期延长和氮添加将延长兴安落叶松幼苗叶黄期,从而增加兴安落叶松幼苗的固碳时间。研究结果可为物候模型发展以及森林生态系统碳估算提供依据。展开更多
基金This project was supported by the National Natural Science Foundation of China
文摘The age structure of a Lurix gmelini population in the northern part of the Great Xingan mountains consists of one to several age waves. Three types (one-, two- and multi-generation populations) , plusing eleven subtypes of age structure can be classified. As the basic unit of the age structure, age waves show an apparent β distribution in the range from 20 to 60 years. The interval between the starting points of two adjacent age waves is more than 100 years. Natural disturbances,especially forest fires that occurred in this area have had an important effect on the age structure. Most of the age waves resulted from forest fires, but the effect of windfall on the age structure also can be revealed through the analysis of young age waves. Generally, high intensity and low frequency fires are usually followed by one-generation populations, while low intensity and high frequency fires by two- or multi-generation populations.
文摘Larix tannin-phenol-formaldehyde (TPF) adhesive, having 60% by weight of phenol bcing replaced, was evaluated for its utilization in plywood. The kinetic characteristic of the TPF resin was investigated through differential scanning calorimetry (DSC) and the results obtained from the DSC scans show that the resin has a little bit different thermochemical behavior from that of phenol-formaldehyde (PF) resin. Two kinds of plywood panels wcre produced using the TPF adhesive in laboratory. The desired test results met the Chinese GB 9846-88 and ZB B70006-88, respectively, and the long assembly time of TPF resin in preparing plywood can be improved by mixing with the filler.All the properties of plywoods bonded with the TPF adhesive were compared with those obtaincd with synthetic PF adhesive.
基金supported by Grants from the National Science and Technology Pillar Program of China(No.2015DAD09B01)
文摘Fifty-three larch interspecific hybrid clones(Larix kaempferi × L.gmelini) and their parent clones were used for growth curve analysis of height variations.The growth curves of the 55 clones were 'S'-shaped and 36 exhibited similar curves as the male parent.The coefficients of the logistic models were higher than 0.943,indicating that our results were effective in the simulation of the growth curves.ANOVA analysis showed significant differences in height of different clones (P\0.01).Average date of maximum height growth was Day 173,and average duration of rapid growth lasted for 50 days.Annual average increase in height was 9.7cm d^(-1) and daily average increase was 0.2 cm.The ratio of GR to the total annual increase in height ranged from 51.2 to 68.8%,with the average being 59.8%.There was a positive correlation between k values and plant heights which benefited from the evaluation of early plant height.There was also a positive correlation between GR(growth stage),GD(plant height) and annual increase in height.These results are informative to the evaluation of the elite clone selection and provide a theoretical basis for breeding and management.
文摘物候是气候变化敏感指标,是陆地生态系统模型的关键参数。目前关于气候变化对物候影响的研究较多,但关于多环境因子交互作用对秋季物候影响的研究尚不充分,制约着物候变化机制的认知与模型发展。以兴安落叶松幼苗叶黄期为研究对象,采用控制实验研究叶黄期对升温、光周期和氮添加变化及其交互作用的响应。结果表明:(1)升温对兴安落叶松幼苗叶黄期的影响较显著,升温使叶黄始期和叶黄普期显著提前,完全变色期不显著推迟;(2)光周期变化对叶黄期的影响极显著,光周期延长使叶黄始期和叶黄普期显著提前,完全变色期显著推迟;(3)叶黄期与氮添加量相关性不显著;(4)升温、光周期和氮添加变化双因子交互作用对叶黄始期和叶黄普期的影响均极显著且均存在极值,但对完全变色期的影响均不显著:升温与光周期延长交互作用使叶黄始期和叶黄普期提前,且在升温1.5℃、光周期14h时最显著;光周期延长与氮添加交互作用使叶黄始期和叶黄普期提前,且在施低氮(5g N m^(-2) a^(-1))、光周期10h时最显著;升温与氮添加交互作用使叶黄始期和叶黄普期提前,且在施高氮(20g N m^(-2) a^(-1))、升温1.5℃时最显著;(5)升温、光周期和氮添加变化交互作用对叶黄始期和叶黄普期影响极显著,对完全变色期的影响不显著。这表明,升温、光周期延长和氮添加将延长兴安落叶松幼苗叶黄期,从而增加兴安落叶松幼苗的固碳时间。研究结果可为物候模型发展以及森林生态系统碳估算提供依据。
