Primary Study on Reasons for the Growth Re-cession of Fragrant Camphor Trees at the West Lake Scenic Area and Diagnosis Procedure

Fragrant camphor tree is the city tree of Hangzhou which takes a large proportion of the ancient trees in Hangzhou City. Recently, with the free open of the attractions around the West Lake and the implementation of the comprehensive pro- ject for protecting the West Lake, a part of ancient fragrant camphor trees are fac- ing problems such as altered living conditons. Some of them are showing a decline in growth vigor or even close to death, which will produce extremely negative influ- ences on the maintaining and sustainable development of the West Lake Scenic Area if without any timely measures for the rescue and rejuvenation of the trees. Therefore, strengthening the protection and management of ancient fragrant camphor trees at the West Lake Scenic Area and carrying out researches on the procedure for diagnosing the reasons for the growth recession of the ancient fragrant camphor trees at the West Lake Scenic Area are of great significance for the future protec- tion and rejuvenation of the ancient trees around the West Lake. The factors influ- encing the growth of ancient trees and indexes for judging the growth condition were listed and the reasons for the growth recession were systematically summa- rized in this paper. In addition, measures for the rejuvenation of the ancient fragrant camphor trees were also simply discussed.

Physiological Changes and Cold Tolerance of Three Camphor Species During Natural Winter Temperature Fluctuations

The dynamic changes in the malondialdehyde（MDA）, superoxide dismutase（SOD）, soluble sugar, proline, and soluble protein contents, as well as the relative electrolyte conductivity and the corresponding cold resistance, of Cinnamomum bodinieri Level., C. camphora L., and C. caudiferum Kisterm were investigated during the winter months of October 2009 to April 2010. During the short period of temperature decline that lasted until mid-December, the changes in the relative electrolyte conductivity and MDA content with temperature were insignificant. In January, SOD activity continued to increase and then peaked as a result of rapid increases in soluble sugar, proline, soluble protein, as well as the inhibition of the relative electrolyte conductivity and decrease in MDA content. These physiological changes protected the camphor trees from cold damage during winter. From February to March, SOD activity and the soluble protein and proline contents increased with the increase in temperature. However, the relative electrolyte conductivity and MDA content decreased, indicating that the cell membrane damaged by low temperature was gradually being repaired. The cold dip in April led to slight increases in the relative electrolyte conductivity and MDA content. Using a fuzzy mathematics method, the cold resistance adaptability of the camphor trees was divided into three periods namely, the enhancement setting stage, the vigorous stage, and the reducing stage. The cold tolerance abilities were ranked as the following order： C. bodinieri Level〉C. camphora L.〉C. caudiferum Kisterm.

Sulfur speciation and bioaccumulation in camphor tree leaves as atmospheric sulfur indicator analyzed by synchrotron radiation XRF and XANES

Analyzing and understanding the effects of ambient pollution on plants is getting more and more attention as a topic of environmental biology.A method based on synchrotron radiation X-ray fluorescence and X-ray absorption near edge structure spectroscopy was established to analyze the sulfur concentration and speciation in mature camphor tree leaves （CTLs）,which were sampled from 5 local fields in Shanghai,China.Annual SO2 concentration,SO42-concentration in atmospheric particulate,SO42-and sulfur concentration in soil were also analyzed to explore the relationship between ambient sulfur sources and the sulfur nutrient cycling in CTLs.Total sulfur concentration in mature camphor tree leaves was 766-1704 mg/kg.The mainly detected sulfur states and their corresponding compounds were ＋6 （sulfate,include inorganic sulfate and organic sulfate）,＋5.2 （sulfonate）,＋2.2 （suloxides）,＋0.6 （thiols and thiothers）,＋0.2 （organic sulfides）.Total sulfur concentration was strongly correlated with sulfate proportion with a linear correlation coefficient up to 0.977,which suggested that sulfur accumulated in CTLs as sulfate form.Reduced sulfur compounds （organic sulfides,thiols,thioethers,sulfoxide and sulfonate） assimilation was sufficed to meet the nutrient requirement for growth at a balanced level around 526 mg/kg.The sulfate accumulation mainly caused by atmospheric sulfur pollution such as SO2 and airborne sulfate particulate instead of soil contamination.From urban to suburb place,sulfate in mature CTLs decreased as the atmospheric sulfur pollution reduced,but a dramatic increase presented near the seashore,where the marine sulfate emission and maritime activity pollution were significant.The sulfur concentration and speciation in mature CTLs effectively represented the long-term biological accumulation of atmospheric sulfur pollution in local environment.

Study on Essential Oil Extracted from Camphor Tree Wood

Essential oil of camphor tree wood was aualyzed by GC-MS system, thirty-three components of which were identified. The essential oil is consisted of monoterpenes and sesquiterpepes （43.73%）, fatty acids （26.61%）, unsaturated fatty acids, ketone and aldehyde components.

Response of soil respiration to nitrogen addition in two subtropical forest types

Anthropogenic activities have increased nitrogen(N)deposition in terrestrial ecosystems,which directly and indirectly affects soil biogeochemical processes,including soil respiration.However,the effects of the increases in N availability on soil respiration are not fully understood.In this study,soil respiration was measured using an infrared gas analyzer system with soil chambers under four N treatments(0,5,15,and 30 g Nm^-2 year^-1 as control,low N(LN),moderate N(MN),and high N(HN),respectively)in camphor tree and slash pine forests in subtropical China.Results showed that soil respiration rates decreased by 37% in the camphor tree forest and 27% in the slash pine forest on average on an annual base,respectively,in the N-fertilized treatments when compared with the control.No significant differences were found in the soil respiration rate among the LN,MN,and HN treatments in both forest types as these fertilized plots reached an adequate N content zone.In addition,soil microbial biomass carbon(C)content and fine root biomass declined in N-treated plots compared to the control.Our results indicated that elevated N deposition might alter the tree growth pattern,C partitioning,and microbial activity,which further affect soil C sequestration by reducing soil respiration in subtropical forests of China.