Difference in cutting age for highest profit by methods for calculating CO<Subscript>2</Subscript> emission trading and the price of CO<Subscript>2</Subscript>

 The amounts of CO₂ that are absorbed and emitted by forest in a model stand area were determined using two calculation methods, namely the flow approach and the stock approach for emission trading, to understand the relationships between the cutting age for the highest profit rate (CAHPR; optimum tree ages to be cut so as to maximize the profit) and (1) the prices of CO₂ and (2) the balance between CO₂ emission and absorption. The resultant CAHPR differed between these two CO₂ accounting methods, which give different tree ages for maximum log volume yield. A rise in CO₂ price caused the CAHPR to approach the tree age of maximum log volume in the flow approach method, and to deviate from the tree age of maximum log volume in the stock approach method. Even at the same CO₂ price, the CAHPR differed between the CO₂ accounting methods. At low CO₂ prices, the CAHPR did not affect situations where the difference of average profit is large by cutting age. On the other hand, the CAHPR was greatly affected at low CO₂ prices when the mean log volume growth changed with tree age. These trends were found to be universal. Received: September 18, 2001 / Accepted: October 25, 2002 Acknowledgments This study is one of the fifth science study subsidy projects of the Japan Forest Technology Association. Correspondence to:K. Sakata     

Vegetative propagation of Colutea istria Mill. from leafy stem cuttings

This study investigates the optimal conditions for the vegetative propagation of the multipurpose leguminous shrub Colutea istria from leafy stem cuttings. The conditions examined included 1) the origin of the cutting (apical, medial or basal), 2) indole-3-butyric acid (IBA) treatment (0, 50, 200 or 400 mg/l), 3) the relative humidity of the propagation environment (high or low), 4) wounding base of cutting, and 5) the season in which the cutting was taken. The rooting ability of the cuttings was significantly influenced by all these factors. Winter cuttings obtained from the middle and base of the branch showed a greater rooting capacity than those harvested from the apical area, while autumn cuttings harvested from the middle and apical areas of the branch showed a greater rooting capacity than those harvested from the base. Winter cuttings showed the best rooting capacity than autumn cuttings. IBA treatment (200 mg/l), high humidity (98-100%), and wounding increased the rooting capacity of the cuttings. The sprout of new leaves was higher in basal cuttings, while IBA and wounding also significantly enhanced the root number of rooted cuttings. A method for vegetatively propagating C. istria plants is given.     

Cutting technic forPinus elliottii plantation of the multi-benefit management pattern

The cutting technic for thePinus elliottii plantation of the multi-benefit management pattern in the hilly region of Jiangxi Province was studied by establishing the model of growth progress according to Richards function and simulating the tending cutting on computer by use of dynamic programming. The results showed that the best time for the initial thinning was at tree age of 8–10 and final cutting was at tree age of 25. The optimal thinning project was 3 times of thinning cutting including the first thinning, and the thinning time was at tree ages of 8, 12 and 16, respectively. Their thinning intensities were separately 950, 700 and 300 trunks per hectare, and the preserved density was 550 trunks per hectare until the final cutting Foundation item: This study was supported by Natural Science Foundation of Jiangxi Province (A grant 0330023) Biography: WANG Qing-chun (1970-), male, Ph. Doctor, Senior Engineer in Academy of Forest Inventory & Planning, Jiangxi, Nanchang 330046, P.R. China. Responsible editor: Song Funan     

激素处理对杨桐扦插生根的影响

通过杨桐扦插激素处理试验表明，NAA处理对杨桐扦插生根有极显著的影响，几种处理中，以100mg／L处理24h和500mg／L处理10S最好，扦插生根率分别达到85％和79．5％，比对照分别高出23．5％和18.0％。杨桐扦插生根属皮部生根型。     

扶芳藤快速扩繁试验

分别采用扦插、播种和嫁接等扩繁方法,对红脉扶芳藤、宽瓣扶芳藤、紫红扶芳藤和金边扶芳藤等品种进行了快速扩繁试验,研究不同扶芳藤品种最适宜的繁殖方式和取材方法及各品种在不同繁殖方式中所需要的适宜条件和处理方法。试验结果得出:7月最适宜扦插,生根最快;红脉扶芳藤的生根能力强于宽瓣扶芳藤和紫红扶芳藤,1 a2、a生枝条强于当年枝,扦插30 d后可以进行移栽;种子经浓度为20 mg/kg的GA3处理最利于生长,根系数和株高均达到最大值。红脉扶芳藤嫁接在丝棉木上,成活率最高,达100%。     

Configuration and development of root systems of cuttings and seedlings of Eucalyptus globulus

Stem cuttings of Eucalyptus globulus are used within tree improvement programs and for mass deployment. To be successful, cuttings must perform as well or better than seedlings. The root systems of cuttings are fundamentally different from those of seedlings. If these differences influence growth, the differences and their consequences must be identified and the propagation system manipulated to improve performance of the propagules.Cuttings are only a viable alternative to seedlings as planting stock if the method of propagation does not affect their growth and development adversely. Full-sibling cuttings and seedlings of Eucalyptus globulus were compared under controlled environmental conditions to minimise extraneous sources of variation, and to establish whether changes in growth or development were induced by propagation. On three occasions over a period of eight weeks root-collar diameter, shoot height, leaf and stem weight, shoot/root ratios and root system morphology were measured on cuttings and seedlings. Seedlings were taller than cuttings throughout the experiment, but both plant types had similar height growth rates. Diameter growth rates were lower in cuttings than seedlings, and there were differences in both height and diameter growth rates between families. Root system configuration differed between the plant types. Seedlings had strongly gravitropic tap-roots, with two types of primary roots from which secondary roots emerged. Cuttings had no tap roots, and the main structural components of their root systems were adventitious roots formed during propagation. Cuttings did not develop further structural roots during the experiment, whereas seedlings continued to develop primary roots. Individual primary roots of cuttings were longer and had larger mid-point diameters than those of seedlings, but the total length of primary roots was greater in seedlings. Seedlings also had a greater number and total length of secondary roots. Shoot/root ratios, calculated from a range of functional measures, were higher in cuttings than seedlings.     

改进马尾松育苗方法的试验

对马尾松采用控制苗木密度、芽苗截根移栽和接种菌根菌等技术进行育苗试验，结果表明：苗木密度应控制在１５０株／ｍ２，芽苗截根以保留主根长度１／２为宜；采用厚环乳牛肝菌进行人工接种效果较好。     

Bulk method of hardwood cutting propagation ofLarix olgensis

Larix olgensis is a major reforestation species in areas of the northeast part of China. Rooted cutting for vegetative propagation on this Larch has been carried out since 1990, and later the bulk method of hardwood cutting propagation also has been studied. The result is as follows: (1) Cuttings from physiologically juvenile trees are easy to root, and develop better roots. In addition, there are many methods to enhance the cuttings rooting. (2) The good time for seedling transplanting is in the middle of August. Treatments with plant hormones and rare-earth compounds can improve the seedling survival rate, and the survival rate of the seedlings soaked in chelate rare-earth molybdenum compound (300×10⁻⁶) for 3 hours reached 94.00%, 19.49% higher than that of the control. (3) Methods of maintaining juvenility such as hedging, is essential to further developments for operational planting of vegetative propagates. Hedges in 5 years old can produce 91.75 shoots per tree, exceeding the control to 152.2%. (Responsible Editor: Zhu Hong)     

板栗扦插繁殖试验

从１９９２－－１９９５年扦插１６０００个插条，成活率由１９９２年的２６％提高到１９９５年的９６％。共繁殖共根苗２２３９株，移栽１０００余株，长势良好。试验认为（１）嫩枝扦插生根率高于硬枝，从实生苗母树采集的插穗经生根剂处理中生根。（２）扦插时间以５月下旬至７月中旬较适宜，６月中，一旬为最佳时间。（３）扦插基质以珍珠岩＋石砂最合适，（４）生根剂以ＰＧＣ，ＰＲＡ液态高深度速蘸法为最佳。     

Combined effect of wood moisture content,drill bit rotational speed and feed rate on drilling resistance measurements in Norway spruce (Picea abies (L.) Karst.)

ABSTRACT

An IML-RESI PD 400 drilling tool and a standard spade drill bit (IML System GmbH, Wiesloch, Germany) were used to study the combined effect of wood moisture content (MC), drill bit rotational speed and feed rate on drilling resistance (DR) and feeding force (FF). Tests were made with Norway spruce (Picea abies (L.) Karst.) conditioned in a normal climate (20°C/65% RH), at 20°C/95% RH, vacuum-pressure impregnated in water, and oven-dried. Rotational speeds and feed rates had an impact on feed rate per cutting edge for the major cutting edge of the drill bit which was used for correlation with DR and FF for various MC. Impact of MC on DR and FF depended on rotational speeds and feed rates of the drill bit. For feed rates per cutting edge less than 0.09?mm, DR was higher for water saturated (WS) specimens. Negligible differences between DR for various MC were found for feed rates per cutting edge between 0.09 and 0.15?mm. DR was higher at low MC for feed rates per cutting edge which were higher than 0.15?mm. FF extremely increased in conditioned (20°C/95% RH) and WS specimens at feed rates per cutting edge less than 0.1?mm.