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951.
952.
The resin content in larch wood is usually determined by the traditionalBenzene-Alcohol Extract Method(BAEM).In order to meet the requirement of production prac-tice,the authors present two simple quick determination methods,IR lamp method and hydrogenperoxide solution method.Compared with the results of traditional method,the results of newmethods are nearly the same as former,therefore,both two methods can reflect the change condi-tion of resin content in wood. 相似文献
953.
A study was conducted in coastal Andhra Pradesh to evaluate current practices and suitability of coastal sandy soils for raising tree plantations. Poor soil moisture retention characteristics of these soils make irrigation an essential, but costly silvicultural practice for obtaining desirable establishment and growth. Saline ground water is the only available source of irrigation. Its use seems safe and successful in such soils. The farmers have adopted a specialized manual splashing technique (Doruvu) of seepage pits for irrigating tree plantations in their establishment phase. This technique was observed to be well suited to the sandy soils. Casuarina equisetifolia and Eucalyptus tereticornis were the two most popular species being afforested. E. camaldulensis is also in an introduction phase. Comparison of growth performance and biomass accumulation by C. equisetifolia and E. tereticornis plantations at different growth stages showed the former to be significantly better than the latter. Build up of the soil organic carbon was also found to be markedly more in comparable C. equisetifolia plantations than those of E. tereticornis. Similarly, the blanketing influence of C. equisetifolia plantations was observed to modify soil temperature extremes considerably more than in the case of E. tereticornis. The findings, indicated a vast scope for utilization of coastal sandy soils for afforestation with the successful use of saline ground waters. 相似文献
954.
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 相似文献
955.
Populus deltoides Bartr., a native of North America, is generally grown in India above latitude 28 °N. One hundred and six clones were evaluated for four years at Raipur situated at 21°12N latitude and 81°36E longitude. These were grown on vertisol soil. Based on growth and survival performance in the nursery for two successive years, nineteen clones were selected for field evaluation. The best five clones (G3, G48, 65/27, D121 and S7C1) were planted in an agrisilviculture system at a spacing of 4 × 4 m with soybean grown as an intercrop. After 4 years these clones had an increment of DBH by 66.5 to 77.5% and of height by 42.2 to 78.6% within one year when compared to that observed at 3 years of age. In rank order of growth the best five clones were 65/27 > G3 > D121 > G48 > S7C1. Total biomass varied between 20.9 to 35.8 Mg ha–1 in different clones. Among the tree components, stemwood accounted for 52–61% of the total biomass, followed by branches (20–25%), bark (9–13%) and leaves (7–10%). No significant variation between net primary productivity and photosynthetic efficiency was found in different clones. Soybean productivity decreased as the trees aged, reaching 40.5 to 58.1% in 4-year-old trees. 相似文献
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香椿种子的发芽率与采种方法及贮藏技术的相关性研究 总被引:2,自引:1,他引:2
传统的采种方法与贮藏技术,导致香椿种子发芽率低、不耐贮藏、极大地影响了香椿的生产和经营。作者通过近年的试验研究,总结出一套香椿种子正确的采种与贮藏技术,可确保香椿种子的以较高的发芽率,常年供应市场需求。 相似文献
960.
Yoshihiro Hayashida 《Journal of Forest Research》2001,6(2):53-61
Multiple regression analyses were applied to the respiration data obtained by an excision method to distinguish between maintenance
and growth respiration in stems ofPinus densiflora. Among several types of regression models, a few models showed marked stability of coefficient of growth related respiration
that are independent of degrees of correlation between predictors and any combinations of predictors. These models predicted
growth respiration as 0.45 g CO2 g (dry weight)−1. At 15°C, sapwood maintenance respiration rate was estimated to 0.72 mg CO2 g−1 day−1. These estimates were not different from the results obtained with standing trees. 相似文献