Quercus gambelii (Gambel’s oak) communities are found in the mountains of the western United States from Wyoming, Colorado, and Utah south into northern Mexico. Leaf gas exchange rates were measured for potential suc...Quercus gambelii (Gambel’s oak) communities are found in the mountains of the western United States from Wyoming, Colorado, and Utah south into northern Mexico. Leaf gas exchange rates were measured for potential successional species in Q. gambelii communities. Daily average light level below the canopy was 125 μmol/m2/sec. Light response curves indicated that Pinus ponderosa and Q. gambelii had high maximum photosynthetic rates (14.13 and 11.21 μmol/m2/sec) and were sun species. Abies concolor (white fir) is a shade species with the lowest photosynthetic rate (3.71 μmol/m2/sec). At low light levels few differences in photosynthetic rates were found between the species. Pinus ponderosa and Q. gambelii maximum photosynthetic rates were reduced 71% - 73% in shade and the shade species maximum photosynthetic rates were reduced by 50% - 57%. Comparing annual gas exchange rates for all species showed that A. concolor had higher gas exchange rates and could replace Q. gambelii. Growth in height of Q. gambelii was a second order quadratic function reaching a plateau of about ten meters between 80 and 95 years. Growth estimates of height of A. concolor in canopy shade were exponential, which would allow seedlings to reach the Q. gambelii canopy in approximately 35 years. Abies concolor wood specific gravity is 56% lower than Q. gambelii, which means more carbon is put into growth in height to reach the canopy at low light levels and low photosynthetic rates. The additional shading it causes would further reduce Q. gambelii photosynthesis rates and prevent self-replacement in these Q. gambelii communities, leading to an A. concolor dominated community.展开更多
The present study corresponds to a descriptive research, whose objective seeks to determine the level of satisfaction of the population of Arequipa city, in respect of public works infrastructure executed in the Avenu...The present study corresponds to a descriptive research, whose objective seeks to determine the level of satisfaction of the population of Arequipa city, in respect of public works infrastructure executed in the Avenues Venezuela and Daniel Alcides Carrion. We designed a survey questionnaire which was applied to 384 people randomly for convenience, in the areas surrounding the road interchange. The results showed that a 65.10% believed that the infrastructure works had a positive impact, in addition to a 52.86% and 7.29% of people who were satisfied and very satisfied respectively, with the vial exchange carried out in the Avenues Venezuela and Daniel Alcides Carrion.展开更多
文摘Quercus gambelii (Gambel’s oak) communities are found in the mountains of the western United States from Wyoming, Colorado, and Utah south into northern Mexico. Leaf gas exchange rates were measured for potential successional species in Q. gambelii communities. Daily average light level below the canopy was 125 μmol/m2/sec. Light response curves indicated that Pinus ponderosa and Q. gambelii had high maximum photosynthetic rates (14.13 and 11.21 μmol/m2/sec) and were sun species. Abies concolor (white fir) is a shade species with the lowest photosynthetic rate (3.71 μmol/m2/sec). At low light levels few differences in photosynthetic rates were found between the species. Pinus ponderosa and Q. gambelii maximum photosynthetic rates were reduced 71% - 73% in shade and the shade species maximum photosynthetic rates were reduced by 50% - 57%. Comparing annual gas exchange rates for all species showed that A. concolor had higher gas exchange rates and could replace Q. gambelii. Growth in height of Q. gambelii was a second order quadratic function reaching a plateau of about ten meters between 80 and 95 years. Growth estimates of height of A. concolor in canopy shade were exponential, which would allow seedlings to reach the Q. gambelii canopy in approximately 35 years. Abies concolor wood specific gravity is 56% lower than Q. gambelii, which means more carbon is put into growth in height to reach the canopy at low light levels and low photosynthetic rates. The additional shading it causes would further reduce Q. gambelii photosynthesis rates and prevent self-replacement in these Q. gambelii communities, leading to an A. concolor dominated community.
文摘The present study corresponds to a descriptive research, whose objective seeks to determine the level of satisfaction of the population of Arequipa city, in respect of public works infrastructure executed in the Avenues Venezuela and Daniel Alcides Carrion. We designed a survey questionnaire which was applied to 384 people randomly for convenience, in the areas surrounding the road interchange. The results showed that a 65.10% believed that the infrastructure works had a positive impact, in addition to a 52.86% and 7.29% of people who were satisfied and very satisfied respectively, with the vial exchange carried out in the Avenues Venezuela and Daniel Alcides Carrion.
