Natural regeneration in Mongolian pine, Pinus sylvesttis var. mongolica, forest at Honghuaerji of China （the original of the natural Mongolian pine, forest on sandy land） was studied in 2004. The total mean values o...Natural regeneration in Mongolian pine, Pinus sylvesttis var. mongolica, forest at Honghuaerji of China （the original of the natural Mongolian pine, forest on sandy land） was studied in 2004. The total mean values of regeneration indexes were higher in mature stands （more than 80% individual stems were older than 50 years）, the maximum of regeneration index reached 29 seedlings, m^ 2, with lowest values in the younger stand, e.g., in 32-year old and 43-year old stands. The stand age was an important factor determining the natural regeneration, which was the best in the older stands in this investigation （e.g. about 80-year old）. The regeneration index seemed not to be closely in relation to canopy openness although Mongolian pine is a photophilic tree species. In each type of gaps, natural regeneration was very well. Regeneration indexes were satisfactory at the south and east edges in the circle gaps; and at the east edge of the narrow-square gaps. Results indicated that Mongolian pine, seedlings could endure shading understory, but it would not enter the canopy layer without gap or large disturbance, e.g., fire, wind/snow damage or clear cutting etc. These results may provide potentially references to the management and afforestation of Mongolian pine, plantations on sandy land in arid and semi-arid areas. Researches such as the comprehensive comparisons on regeneration, structure and ecological conditions and so on between natural Mongolian pine, forests and plantations should be conducted in the future.展开更多
To estimate the mean value of surface soil water content rapidly,accurately,and nonintrusively,field investigations on soil electrical resistivity(SER)with the Yokogawa 324400 earth resistivity meter and the surface(0...To estimate the mean value of surface soil water content rapidly,accurately,and nonintrusively,field investigations on soil electrical resistivity(SER)with the Yokogawa 324400 earth resistivity meter and the surface(0-150 cm)soil water content(SWC)with time domain reflectometry(TDR),together with the abiotic factors including soil texture,structure. and salinity concentrations were conducted in the Mongolian pine(Pinus sylvestris var.mongolica)plantations on a sandy land.The measurement of SER was based on the 4-probe Wenner configuration method.Relationships between the values of SWC and SER were obtained based on analysis of the abiotic factors of the research site,which play a key role in affecting the soil electrical resistivity.Results indicate that the SER meter could be used to estimate the mean value of SWC in the Mongolian pine plantations on the sandy land during the growing seasons.The bulky nature of the equipment simplified the cumbersome measurements of soil water content with the general methods.It must be noted that the Wenner configuration method could only provide the mean values of the SWC,and the soil texture,structure, temperature,and solute concentrations influenced the SER and further affected the estimation of the SWC by the SER meter.Therefore,the results of this study could be applied on a sandy land during the growing seasons only.However, the SWC of other soil types also may be obtained according to the individual soil types using the procedures of this study.展开更多
In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris v...In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris var. mongolica trees from two provenances （natural forests and plantations）. The results indicated that natural tree needles had lower N, P and C concentrations, and higher K concentrations than those of plantation tree needles. For plantation tree needles, ratios of N： P, P. K and N： K increased with tree age before 45 years old; but they were not clear for the natural tree needles. Compared with the conclusions reported on Pinus spp., we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles. This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var. mongolica on sandy land. However, foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp. （〉4.80 g kg-1）.The N： P ratio of natural needles was in the adequate ranges, but N： P ratio of plantation needles was out of the adequate ranges. These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations. If only considering the foliar nutrient concentrations of P sylvestris var. mongolica from different provenances, it might be concluded that the degradation phenomenon of P. sylvestris var. mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P, but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients. The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.展开更多
基金The research was supported by innovation research project of Chinese Academy of Sciences （KZCX3-SW-418）, the 100-Young-Researcher-Project of Chinese Academy of Sciences, and by Nature Science Foundation of Liaoning Province （20021006）. Acknowledgements We thank Professor Hexin Wang （Dalian University, China）, Dr. Professor Zeng Dehui, and the graduate students in research group of Ecology and Management of Secondary Forest （Institute of Applied Ecology, Chinese Academy of Sciences） for their valuable discussion. We are grateful to Mr. Tao Yang （Institute of Applied Ecology, Chinese Academy of Sciences） for his field work. We also thank Dr. Professor Qingcheng Wang （Northeast Forestry University, China）, Mr. Menqi Tu and Mr. Yuxiang Ge （Honghuaerji Forestry Bureau, Inner Mongolia, Hulunbeier, China） for providing the convenience during the field investigation.
文摘Natural regeneration in Mongolian pine, Pinus sylvesttis var. mongolica, forest at Honghuaerji of China （the original of the natural Mongolian pine, forest on sandy land） was studied in 2004. The total mean values of regeneration indexes were higher in mature stands （more than 80% individual stems were older than 50 years）, the maximum of regeneration index reached 29 seedlings, m^ 2, with lowest values in the younger stand, e.g., in 32-year old and 43-year old stands. The stand age was an important factor determining the natural regeneration, which was the best in the older stands in this investigation （e.g. about 80-year old）. The regeneration index seemed not to be closely in relation to canopy openness although Mongolian pine is a photophilic tree species. In each type of gaps, natural regeneration was very well. Regeneration indexes were satisfactory at the south and east edges in the circle gaps; and at the east edge of the narrow-square gaps. Results indicated that Mongolian pine, seedlings could endure shading understory, but it would not enter the canopy layer without gap or large disturbance, e.g., fire, wind/snow damage or clear cutting etc. These results may provide potentially references to the management and afforestation of Mongolian pine, plantations on sandy land in arid and semi-arid areas. Researches such as the comprehensive comparisons on regeneration, structure and ecological conditions and so on between natural Mongolian pine, forests and plantations should be conducted in the future.
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KZCX3-SW-418)the 100 Talents Program of the Chinese Academy of Sciences,China.
文摘To estimate the mean value of surface soil water content rapidly,accurately,and nonintrusively,field investigations on soil electrical resistivity(SER)with the Yokogawa 324400 earth resistivity meter and the surface(0-150 cm)soil water content(SWC)with time domain reflectometry(TDR),together with the abiotic factors including soil texture,structure. and salinity concentrations were conducted in the Mongolian pine(Pinus sylvestris var.mongolica)plantations on a sandy land.The measurement of SER was based on the 4-probe Wenner configuration method.Relationships between the values of SWC and SER were obtained based on analysis of the abiotic factors of the research site,which play a key role in affecting the soil electrical resistivity.Results indicate that the SER meter could be used to estimate the mean value of SWC in the Mongolian pine plantations on the sandy land during the growing seasons.The bulky nature of the equipment simplified the cumbersome measurements of soil water content with the general methods.It must be noted that the Wenner configuration method could only provide the mean values of the SWC,and the soil texture,structure, temperature,and solute concentrations influenced the SER and further affected the estimation of the SWC by the SER meter.Therefore,the results of this study could be applied on a sandy land during the growing seasons only.However, the SWC of other soil types also may be obtained according to the individual soil types using the procedures of this study.
基金The research was supported by Innovation Research Project of Chinese Academy of Sciences (KZCX3-SW-418), and the 100 Young Researcher Project of Chinese Academy of Sciences.
文摘In order to examine the causes of degradation of Pinus sylvestris var. mongolica plantations on sandy land, the foliar concentrations of N, P, K and C were analyzed and compared between the field grown P. sylvestris var. mongolica trees from two provenances （natural forests and plantations）. The results indicated that natural tree needles had lower N, P and C concentrations, and higher K concentrations than those of plantation tree needles. For plantation tree needles, ratios of N： P, P. K and N： K increased with tree age before 45 years old; but they were not clear for the natural tree needles. Compared with the conclusions reported on Pinus spp., we found that the foliar N and P concentrations were in the optimal range for both natural and plantation tree needles. This result suggested that N or P might not be the absolute limit factors in plant nutrient for P sylvestris var. mongolica on sandy land. However, foliar K concentrations in both natural and plantation tree needles were much lower than those reported on Pinus spp. （〉4.80 g kg-1）.The N： P ratio of natural needles was in the adequate ranges, but N： P ratio of plantation needles was out of the adequate ranges. These results indicated that there was a better balanced nutrition status in the natural forest than in the plantations. If only considering the foliar nutrient concentrations of P sylvestris var. mongolica from different provenances, it might be concluded that the degradation phenomenon of P. sylvestris var. mongolica plantations was not induced by nutrition deficiency of absolute nutrients of N and P, but might be induced by other mineral nutrients or by the effectiveness of N and P nutrients. The unbalanced nutrition status and relatively quick decomposition of needles in the plantations might also contribute to the degradation.
