Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

The response of Chinese fir forest tree ring growth to climate change in China’s Dagangshan region

100%

Shengtao L., Peng G., Panwei L., Xiang N., Bing W.

Polish Journal of Environmental Studies

2019

tom 28

nr 4

Chinese fir (Cunninghamia lanceolata (Lamb) Hook.) in the Dagangshan region of Jiangxi Province in southern China was selected to explore the impact of climatic factors on tree ring width growth. Results showed that the signal-to-noise ratio (SNR) and mean sensitivity (MS) were large while the first order autocorrelation coefficient (FOAC) was small, and the chronology contains abundant climatic information. The tree ring width index of Chinese fir was significantly positively correlated with the precipitation in December of the previous year and June of the current year, and significantly negatively correlated with that in the current May and August. The tree ring width index was significantly positively correlated with the temperature in April and May of the current year, but significantly negatively correlated with that in July of the current year. The tree ring width index had a good change consistency with the warmth index (Wi) and humidity index (Hi). The response function of Chinese fir ring width analysis shows that the warmth index is the main factor affecting tree ring growth, followed by the humidity index, mean annual precipitation, and mean annual temperature. The comprehensive effect of temperature and precipitation factors have significant influence on the tree ring width growth of Chinese fir. Results can provide a scientific basis for studying the effect of climatic factors on tree growth in sub-tropical regions in China and many other parts of the world.

Spatial variability of CO2, CH4, and N2O fluxes during midsummer in the steppe of Northern China

86%

Jinzhong C., Xinqing L., Theng B. K. G., Fang B., Fang Y., Bing W., Like Z.

Polish Journal of Environmental Studies

2014

tom 23

nr 2

Spatial variability is a major source of uncertainty in estimating the fluxes of greenhouse gases between steppe and atmosphere. The fluxes of CO₂, CH₄, and N₂O were carried out between 08:00 and 10:00 h. of the following day during the midsummer period from a transect (area: 5.25×10⁶ ha) in the semiarid steppe of northern China, using the dark static chamber technique and gas chromatography. Two land uses were chosen for this study: soils with plant covers and bare soils. Daily average GHG fluxes from the steppe transect were: 1.3×10⁵ t C for CO₂, -66.3 t C for CH₄, and 1.1 t N for N₂O. The emission of CO₂ from soils with plant cover was significantly higher (P < 0.05) than that from the corresponding bare soils. The canopy effect, however, was observed for neither CH₄ (P = 0.058) nor N₂O (P = 0.772). Air temperature and relative humidity were the major factors affecting the diurnal variation in site-based CO₂ flux (P < 0.05), while soil pH controlled its spatial variation (P < 0.05). The spatial uptake of CH₄ correlated negatively with soil total N (TN) content (P < 0.05), while the flux of N₂O significantly increased with soil organic carbon (P = 0.031) and TN (P = 0.022), indicating that soil organic matter is an important factor determining the N₂O flux in the steppe of northern China.

Ograniczanie wyników

2 Polish Journal of Environmental Studies

2 Bing W.

1 Fang B.

1 Fang Y.

1 Jinzhong C.

1 Like Z.

1 Panwei L.

1 Peng G.

1 Shengtao L.

1 Theng B. K. G.

1 Xiang N.

1 Xinqing L.

1 2019

1 2014

Wyniki wyszukiwania

The response of Chinese fir forest tree ring growth to climate change in China’s Dagangshan region

Spatial variability of CO2, CH4, and N2O fluxes during midsummer in the steppe of Northern China