Chinese Fir Cunninghamia Lanceolata Research Articles

Carbon sequestration and storage capacity of Chinese fir at different stand ages

In southern China, Chinese fir Cunninghamia lanceolata is one of the most important native conifer trees, widely used in afforestation programs. This area has the largest forestland atmospheric carbon sink, and a relatively young stand age characterizes these forests. However, how C. lanceolata forests evolved regarding their ability to sequester carbon remains unclear. Here we present data on carbon storage and sequestration capacity of C. lanceolata at six stand ages (5−, 10−, 15−, 20−, 30− and 60 − year−old stands). Results show that the carbon stock in trees, understory, vegetation, litter, soil, and ecosystem significantly increased with forest age. The total ecosystem carbon stock increased from 129.11 to 348.43 Mg ha−1 in the 5− and 60 − year−old stands. The carbon sequestration rate of C. lanceolata shows an overall increase in the first two stand intervals (5–10 and 10–15), peaks in the 15–20 stand intervals, and then decreases in the 20–30 and 30–60 stand intervals. Our result revealed that carbon sequestration rate is a matter of tree age, with the highest sequestration rates occurring in the middle age forest (15–20 − year−old). Therefore, this information may be useful for national climate change mitigation actions and afforestation programs, since forests are primarily planted for this purpose.

Effects of Drought Stress on Non-Structural Carbohydrates in Different Organs of Cunninghamia lanceolata.

The Chinese fir Cunninghamia lanceolata (Lamb.) Hook. is an important timber conifer species in China. Much has been studied about Chinese fir, but the distribution of non-structural carbohydrates (NSCs) among different organs (needles, branch, stem, and roots) under drought stress remains poorly understood. In this study, we used one-year-old C. lanceolata plantlets to evaluate the effects of simulated drought under four water regimes, i.e., adequate water or control, light drought, moderate drought, and severe drought stress corresponding to 80%, 60%, 50%, and 40%, respectively of soil field maximum capacity on various NSCs in the needles, branch, stem and roots. The degree and duration of drought stress had significant effects on fructose, glucose, sucrose, soluble sugar, starch, and NSC content in various organs (p < 0.05). Fructose content increased in stem xylem, stem phloem, and leaves. Glucose and sucrose content declined in stem and branch xylem under light drought stress and moderate drought stress, and increased under severe drought stress conditions. Soluble sugars content declined, and starch content increased in leaf and branch phloem, but the latter could not compensate for soluble sugar consumption in the whole plant, and therefore, total NSCs decreased. Correlation analysis showed that a significant positive correlation existed in the soluble sugar content between leaves and roots, and between xylem and phloem in the stems and branches. Chinese fir appears to have different NSCs distribution strategies in response to drought stress, viz., allocating more soluble sugars to fine roots and increasing starch content in the needles, as well as ensuring osmosis to prevent xylem embolism. Our study may broaden the understanding of the various mechanisms that Chinese fir and other plants have to enhance their tolerance to drought stress.

Food Preferences of Workers of Coptotermes formosanus (Isoptera: Rhinotermitidae)

Coptotermes formosanus Shiraki is an amphibious termite which severely damages wood components of housing construction, stored cellulose materials, living trees, and communication facilities. The food preference of this termite was investigated in laboratory conditions. Our research results indicated that among 8 kinds of woods (teak Tectona grandis, Chinese fir Cunninghamia lanceolata, oak Quercus mongolica, taxis Melia azedarach, birch Betula allegansis, beech Fagus syliatica, pine Pinus massoniana, and poplar Populus tremula), the consumption rate of pine wood by C. formosanus (30.46%) is higher than that of seven other species of wood. After pine was treated by eight different methods, the pine wood treated repeatedly (three times) by the method of dipping 24 hours in water and drying in the sun (SD method) was significantly preferred by C. formosanus. When adding 30% sugar into water for treatment of pine wood blocks in the SD method, the pine wood blocks attracted more termites to feed compared to other concentrations of sugar in water. Moreover, Adding 10% Formosan subterranean termite nest material into 30% sugar solution increased the preference to the treated pine wood blocks by C. formosanus. This information shows that C. formosanus likes to feed on pine wood blocks treated repeatedly by the method of dipping in mixed solutions of Formosan subterranean termite nest material and 30% sugar for 24 hours and drying in the sun.