December Of Previous Year Research Articles

Radial growth responses of three coniferous species to climate change on the southern slope of Funiu Mountains, China.

Funiu Mountains are located in a transition region between warm temperate zone and northern subtropical region, where a variety of plant species are distributed with sensitive response to climate change. Their response characteristics to climate change are still unclear. We developed the basal area increment (BAI) index chronologies of Pinus tabuliformis, P. armandii, and P. massoniana in the Funiu Mountains to examine their growth trend and their sensitivity to climatic change. The results showed that the BAI chronologies gave a clue that the three conife-rous species had similar radial growth rate. The large Gleichlufigkeit (GLK) indices among the three BAI chronologies also indicated that the three species had a similar growth trend. Results of correlation analysis showed that the three species also had similar response to climatic change to a certain extent. Radial growth of all the three species was significantly positively correlated with the total monthly precipitation in December of previous year and June of the current year, but negatively correlated with the precipitation in September and the mean monthly temperature in June of the current year. There were some differences in the responses of the three coniferous to climate change. P. massoniana had a significant negative correlation with the mean temperature in March, and a significant positive correlation with the precipitation in March, while P. armandii and P. massoniana were affected negatively by the maximum temperature in August. Results of the moving correlation analysis showed that the three coniferous species had some similar sensitivity to climate change. Their positive responses to precipitation in previous December consistently increased, as well as the negative correlation with precipitation in current September. As to P. masso-niana, they had a relatively stronger climatic sensitivity and higher stability than the other two species. It would be more suitable for P. massoniana trees on the southern slope of the Funiu Mountains under global warming.

Sensitivity of Soil Water in Community Atmosphere Model (CAM3) for Indian Summer Monsoon (ISM)

The study has been attempted to investigate the relationship between the soil-water and the Indian summer monsoon (ISM) rainfall through the simulation of a global climate model named Community Atmosphere Model (CAM3). Two sets of simulation have been done during monsoon season for the years 2009 to 2012 using the pre-monsoon (May) and the previous winter season (December of previous year) state of soil-water as the model initial conditions. The control simulation and four sensitivity cases assuming 25% and 50% dryer and wetter soil-water respectively have been considered for all the aforesaid four years and for both the set of experiments. It has been observed that the impact of upper level soil-water persist for 15 to 20 days of simulation during the summer monsoon; the middle and lower layer soil state persist for a longer period of time due to its slow-varying nature with time. The daily surface temperature shows strong coupling with the upper layer of soil-water. When taken into comparison with the wet soil conditions, the dry soil state in most of the circumstances causes less rainfall. The Pearson correlation coefficient (PCC) and partial correlation technique have been implied to demonstrate the relationship between the daily soil-water columns, subsequent 30-days accumulated rainfall and past 21-days accumulated rainfall. Strong negative correlation has been reported between the soil-water and subsequent 30-days accumulated (All-India Rainfall) AIR for different simulation cases with dry soil conditions; however, the relation weakened and turned positive over some parts of the region for the simulations with wet soil conditions.

Growth responses of broad-leaf and Korean pine mixed forests at different successional stages to climate change in the Shengshan Nature Reserve of Heilongjiang Province, China

Aims This research examined the different response of tree growth to climate change at the early, middle, late and matured successional stages of Korean pine (Pinus koraiensis) and broadleaf mixed forest. Methods This research used dendroecological methods to analyze radial growth at different successional stages of Korean pine forests in response to climatic change in the Shengshan Nature Reserve of Heilongjiang. Important findings Chronology statistics indicated that the sensitivity of radial growth to inter-annual climate variability decreased from early to later successional stage. Meanwhile, the influence of some climate indices to radial growth also changed during the successional process. Radial growth of matured forest was positively re- lated to mean monthly temperature in June and December of previous year, revealing an obvious lag of temperature. The ring-width of matured forest had a negative correlation with mean monthly temperature but a positive correlation with monthly precipitation in June of current year, reflecting the limiting role of growing sea- son water availability. However, these limiting effects gradually disappeared towards the earlier stages of forest succession. On the contrary, the growth of early successional forest was negatively correlated to precipitation in June of previous year, and this effect disappeared towards the later successional stages. These differences revealed increased demand of water by dominant species from early to later successional stages. A moving correlation analysis showed that the increased warming and drying climate in the research area had both positive and negative influences on radial growth of each forest type. Earlier successional forests did not show clear long-term growth