After the investigation and long-lerm research, the structure, succession, energy flow,nutrient and water cycles, produetivity, ete. of Mongolian oak (Quercus mongolica) forest ecosysteins are synthetically summarized...After the investigation and long-lerm research, the structure, succession, energy flow,nutrient and water cycles, produetivity, ete. of Mongolian oak (Quercus mongolica) forest ecosysteins are synthetically summarized. The oak, with a simple stand composition, naturally distributes at hilltops, where the soil is arid and inlfertile and lots of tree species can not grow, and stabilizes for a long period for its high adaptive capacity and long longevity, but it will grow better in good sites.Compared with other forest ecosystems in temperate zone, the oak forest has not only more intensive biological cycles of nutrients but higher productivity as well. Among the nine elements determined, the concentrations of Ca and Zn are the highest and lowest, amounling to 41 .99% and 0.0015%, respectiveiv. In the vegetation, the largest nutrient pool is root svstem, making up 47.75%, and the trunk steps the following, 25. 13%. Among the main secondary forest types in Maoershan region, the oak stands have not only highest biomass but best biomass structure for in which the biomass of trcc stratum reaches 95.6% of the total of the stands and that of trunk does 68.9% of the total of the tree. The oak stands have high steinflow, which amounts to 15.6% of the precipitation and carries a lot of nutrients, and high evapotranspiration, which is as high as 504. 1 mm and for which 77.45% of the total radiation (123.3 KJ. cm-2) is consumed as latent heat transter in the growing reason. The clearcutting of the oak stands will result in not only inereasing the surlace runoff and interflow percentage but also intensitying the loses of N, Ca, Mg and Fe. Finally, it is proposed to pay a great attention to cnltivating.rejuvenating and even planting the oak as high yield timber and water conservation forests.展开更多
The height fast growing period of oak seedling (Quercus mongolica) was between 25 to 30 years old but the diameter varied greatly. The maximum diurnal height increment of the investigated oak tree reached 3. 3 cm, but...The height fast growing period of oak seedling (Quercus mongolica) was between 25 to 30 years old but the diameter varied greatly. The maximum diurnal height increment of the investigated oak tree reached 3. 3 cm, but at daytime it was much greater than at night. The oak trees usually sprouted twice and even treble in the growing season. In natural oak stands. the volume rarely exceeded 200 m3/hm2 and the mean volume increment was only about 2 m3/hm2展开更多
Four alternative functions are used for lilting tree height and diameter growth models for mongolian oak(Quercus mongolica Fisch et Turcz)The data set includes 1250 random trees and 755 dominant trees coming from 510l...Four alternative functions are used for lilting tree height and diameter growth models for mongolian oak(Quercus mongolica Fisch et Turcz)The data set includes 1250 random trees and 755 dominant trees coming from 510lemporary plots The resultsshow that the Richads function is the best model for predicting height diameter at breast height(DBH) and dominant height from age The average growth curveof domnant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set The Mischerlic function is the bestmodel for estimating height and dominam height from DBH展开更多
The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the N...The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the Nam-San site in Seoul, Korea for the growing period from early May to late October in 2010. The empirical models include the attenuation function of photosynthetic photon flux density (PPFD) (r2 = 0.98-0.99, p r2 = 0.99, p < 0.001) derived from the measured data at several levels within the canopy. The incident PPFD at each level within canopy significantly varies diurnally and seasonally due to the seasonal variation of the total plant area index (TPAI = leaf area index + wood silhouette area index) and the light shielding effect of light path-length through the canopy in association with the variation of solar elevation angle. Consequently, a remarkable seasonal variation of the total canopy net photosynthesis rate of Q. mongolica forest stand is found for its growing period. The PPFD exceeding 1000 μmol m-2·s-1 is found to cause the decrease of net photosynthesis rate due to the thermal stress in the early (May) and late (September) growing period. During the whole growing season, the estimated total canopy net photosynthesis rate is found to be about 3.3 kg CO2 m-2.展开更多
文摘After the investigation and long-lerm research, the structure, succession, energy flow,nutrient and water cycles, produetivity, ete. of Mongolian oak (Quercus mongolica) forest ecosysteins are synthetically summarized. The oak, with a simple stand composition, naturally distributes at hilltops, where the soil is arid and inlfertile and lots of tree species can not grow, and stabilizes for a long period for its high adaptive capacity and long longevity, but it will grow better in good sites.Compared with other forest ecosystems in temperate zone, the oak forest has not only more intensive biological cycles of nutrients but higher productivity as well. Among the nine elements determined, the concentrations of Ca and Zn are the highest and lowest, amounling to 41 .99% and 0.0015%, respectiveiv. In the vegetation, the largest nutrient pool is root svstem, making up 47.75%, and the trunk steps the following, 25. 13%. Among the main secondary forest types in Maoershan region, the oak stands have not only highest biomass but best biomass structure for in which the biomass of trcc stratum reaches 95.6% of the total of the stands and that of trunk does 68.9% of the total of the tree. The oak stands have high steinflow, which amounts to 15.6% of the precipitation and carries a lot of nutrients, and high evapotranspiration, which is as high as 504. 1 mm and for which 77.45% of the total radiation (123.3 KJ. cm-2) is consumed as latent heat transter in the growing reason. The clearcutting of the oak stands will result in not only inereasing the surlace runoff and interflow percentage but also intensitying the loses of N, Ca, Mg and Fe. Finally, it is proposed to pay a great attention to cnltivating.rejuvenating and even planting the oak as high yield timber and water conservation forests.
文摘The height fast growing period of oak seedling (Quercus mongolica) was between 25 to 30 years old but the diameter varied greatly. The maximum diurnal height increment of the investigated oak tree reached 3. 3 cm, but at daytime it was much greater than at night. The oak trees usually sprouted twice and even treble in the growing season. In natural oak stands. the volume rarely exceeded 200 m3/hm2 and the mean volume increment was only about 2 m3/hm2
文摘Four alternative functions are used for lilting tree height and diameter growth models for mongolian oak(Quercus mongolica Fisch et Turcz)The data set includes 1250 random trees and 755 dominant trees coming from 510lemporary plots The resultsshow that the Richads function is the best model for predicting height diameter at breast height(DBH) and dominant height from age The average growth curveof domnant height is used as a guide curve for the construction of a site index table which is partially validated using an independent data set The Mischerlic function is the bestmodel for estimating height and dominam height from DBH
文摘The canopy net photosynthesis rate of Mongolian oak (Quercus mongolica) tree species that are dominant in East Asia and Korea is estimated with empirical models derived from field experimental data obtained from the Nam-San site in Seoul, Korea for the growing period from early May to late October in 2010. The empirical models include the attenuation function of photosynthetic photon flux density (PPFD) (r2 = 0.98-0.99, p r2 = 0.99, p < 0.001) derived from the measured data at several levels within the canopy. The incident PPFD at each level within canopy significantly varies diurnally and seasonally due to the seasonal variation of the total plant area index (TPAI = leaf area index + wood silhouette area index) and the light shielding effect of light path-length through the canopy in association with the variation of solar elevation angle. Consequently, a remarkable seasonal variation of the total canopy net photosynthesis rate of Q. mongolica forest stand is found for its growing period. The PPFD exceeding 1000 μmol m-2·s-1 is found to cause the decrease of net photosynthesis rate due to the thermal stress in the early (May) and late (September) growing period. During the whole growing season, the estimated total canopy net photosynthesis rate is found to be about 3.3 kg CO2 m-2.
