共查询到20条相似文献，搜索用时 546 毫秒
1.
2.
能源植物是开发生物质能的基础.对岷江上游能源植物资源的调查研究结果表明,该区能源植物种类涵盖30科44属54种,其中蕨类植物2科2属2种,裸子植物6科12属18种,被子植物22科30属34种.植物类型以乔木为主,占该区所有被统计能源植物的81.48%,灌木和草本分别占11.11%和7.41%.资源主要集中在低海拔地区.某些物种分布范围狭窄或处于濒危状态.一些植物拥有多种开发利用价值.建议在不同海拔地区建立一定数量针对植物资源的自然保护区,并深入开展资源调查研究工作,探索资源开发与经营的合理模式,为21世纪开发生物质能提供材料基础和理论依据. 相似文献
3.
4.
西双版纳热带天然森林生态服务功能价值评估 总被引：2，自引：1，他引：1
对西双版纳热带天然森林生态服务功能进行了估算,其总价值为1 002.33亿元/a,其中水源涵养价值为470.73亿元/a,占生态服务功能总价值的46.96%;生物多样性保护价值为277.75亿元/a,占27.71%;保育土壤价值为129.32亿元/a,占12.90%;固碳释氧价值为98.66亿元/a,占9.84%;净化大气环境价值为16.04亿元/a,占1.60%;积累营养物质价值为9.83亿元/a,占0.98%.单位面积热带天然森林生态服务功能价值为10.83万元/(hm2.a),相当于全国平均水平的1.96倍,云南省平均水平的1.60倍. 相似文献
5.
研究了观光木(Tsoongiodendron odorum)、女贞(Ligustrum lucidum)、山杜英(Elaeocarpus sylves-tris)、乳源木莲(Manglietia yuyuanensis)和乐昌含笑(M ichelia chapensis)幼苗的养分积累和分布。结果表明:观光木各器官干重为根>叶>干,女贞为干>根>叶>枝,山杜英为枝>叶>根>干,乳源木莲为根>干>叶,乐昌含笑为叶>干>根>枝。各树种干的养分浓度最低。除了观光木外,其余树种均以叶的养分浓度为最高。观光木的养分贮量为根>叶>干,女贞和山杜英为叶>枝>根>干,乳源木莲为叶=干>根,乐昌含笑为叶>干=根>枝。5种幼苗各器官的养分贮量多为N>K>P。 相似文献
6.
为找出最优育种方法,提高发芽率,获取更多优质种苗,从而为漆树种质资源及产业发展提供指导,采用三因素(98%的H_2SO_4、400 mg/L的GA3、砂藏时间)三水平的全因素试验方法,每处理设置单个变量,共计27个处理组合,对不同种源漆树种子萌发条件进行研究。结果表明:A种源漆树种子的最佳萌发条件为,98%的H_2SO_4处理30 min+400 mg/L GA3处理60 min+砂藏30 d;B种源漆树种子萌发率最高的条件为,98%的H2SO4处理30 min+400 mg/L GA3处理60 min+砂藏20 d;C种源漆树种子萌发率最高的条件为,98%的H_2SO_4处理30 min+400 mg/L GA3处理120 min+砂藏20 d。98%的H2SO4处理时间、400 mg/L GA3处理时间、砂藏时间对不同种源的漆树种子发芽率、芽长、芽粗均存在极显著影响。 相似文献
7.
广州旧城区绿地建设对策研究 总被引：1，自引：0，他引：1
通过分析城市旧城区绿地建设普遍存在的困难,在建设策略上,提出规划建绿、文化建绿、见缝插绿、立体增绿、临时建绿、拆危建绿、绿地提升、保存大树等针对旧城区绿地建设的对策。 相似文献
8.
我国木材及林产品供需平衡研究 总被引：10，自引：0，他引：10
在分析我国森林资源与木材供求状况,以及木材需求趋势与供需缺口的基础上,就如何实现我国木材与林产品自给,达到供需平衡进行了研究。研究表明,大力发展工业人工林,定向培育、提供适用木材,高效利用木材、节约林木资源、增加林产品供给,扩大原料来源、开发利用生物质资源生产林产品,是实现我国木材与林产品供需平衡的行之有效的途径。 相似文献
9.
Eighteen clones of Eucalyptus tereticornis (Sm.) were evaluated for three years by adopting randomized block design for various growth parameters at Hoshiarpur, Punjab,
India and compared with two checks. Significant variations were recorded for height, diameter at breast height (DBH) and clear
bole height (CBH). The broad sense heritability was low to moderate for both height and CBH. The genetic gain for height and
CBH increased substantially per se with the increase in age of trees. The average genetic gain for three years was recorded maximum for height (159.60%) followed
by DBH (110.97%) and CBH (70.34%). Clone 17 attained maximum DBH over other genotypes for second and third year followed by
clones 14 and 11. Clone 5 showed an upward trend for DBH and maintained its superiority for CBH as the age of the tree increased.
Similarly, clone 11 changed its ranking from 9th to 8th to 3rd for DBH and from 9th to 4th to 2nd for CBH, respectively for
the age of one, two and three years. Nonetheless, clones 6 and 10 performed poorly for all the characters studied. Clones
17, 14 and 5 were found to be the most promising clones for commercial deployment. 相似文献
10.
11.
S. Craig DeLong Glenn D. Sutherland Lori D. Daniels Ben H. Heemskerk Ken Olaf Storaunet 《Forest Ecology and Management》2008,255(10):3613-3620
Patterns of tree mortality, rates and type of tree and snag fall, and relationships between snag characteristics and potential wildlife habitat value were estimated for hybrid spruce (Picea glauca (Moench) Voss × engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) in east-central British Columbia in order to provide important parameters for deadwood modelling. We sampled 172 snags (52 spruce and 120 fir) for species, size, morphological, and habitat attributes, and used dendroecological techniques on a subsample of these (n = 158) to estimate year of death. Input of snags appeared to occur at a nearly constant rate in these stands. Estimated annual tree fall, including live trees and snags, was 5.3% for hybrid spruce and 6.1% for subalpine fir and stem breakage was more frequent than uprooting. Long-term annual snag fall rates were 4.6% for hybrid spruce and 2.9% for subalpine fir. Discriminant analysis based on time since death correctly classified snags into three decay classes for 85% and 72% of spruce and fir, respectively. Snags that potentially could provide important functions for wildlife habitat were more prevalent in fresh and intermediate classes for hybrid spruce and in intermediate and old classes for subalpine fir. The results provide valuable parameters for further development of deadwood models, which are an important tool for development of best practices for deadwood management. 相似文献
12.
R. M. Nelson Jr. 《Wood Science and Technology》1986,20(3):235-251
Summary A model for isothermal bound water diffusion in wood is derived from Babbitt's (1950) analysis of diffusion in adsorbing solids. Calculations of the energy required for water molecules to become dissociated from their sites is identified as one component of the activation energy for diffusion. Consideration of the resistance to diffusion leads to a second component of activation energy associated with overcoming the attraction of water molecules for themselves. Also, an approximate expression for the resistance coefficient is developed. These results are combined into a transport model for bound water. The model shows that equations for bound water movement based on fluid mechanics (Babbitt 1950) and thermodynamics (Katchalsky, Curran 1965) are identical when the driving force for diffusion is defined as the moisture flux per unit transport coefficient. Activation energies and diffusion coefficients derived from the model compare favorably with literature values.The author wishes to thank Dr. Christen Skaar for his interest and advice during preparation of this paper for publication 相似文献
13.
14.
15.
浙江省食用菌重金属背景值及质量安全评价 总被引：5，自引：0，他引：5
在浙江食用菌生产基地、超市和农贸市场实地抽样检测,对数据进行统计分析,提出浙江省食用菌重金属背景值.研究结果显示:浙江省鲜食用菌重金属元素背景值为铅0.078 mg·kg~(-1)、镉0.036 mg·kg~(-1)、汞0.009 mg·kg~(-1)、砷0.029 mg·kg~(-1),干食用菌重金属背景值为铅0.452 mg·kg~(-1)、镉0.254 mg·kg~(-1)、汞0.044 mg·kg~(-1)、砷0.150 mg·kg~(-1),鲜香菇重金属背景值为铅0.074 mg·kg~(-1)、镉0.122 mg·kg~(-1)、汞0.009 mg·kg~(-1)、砷0.030 mg·kg~(-1),鲜平菇重金属背景值为铅0.068 mg·kg~(-1)、镉0.026 mg·kg~(-1)、汞0.008 mg·kg~(-1)、砷0.029 mg·kg~(-1),鲜蘑菇重金属背景值为铅0.149 mg·kg~(-1)、镉0.019 mg·kg~(-1)、汞0.038 mg·kg~(-1)、砷0.094 mg·kg~(-1),鲜金针菇重金属背景值为铅0.083 mg·kg~(-1)、镉0.013 mg·kg~(-1)、汞0.008 mg·kg~(-1)、砷0.020 mg·kg~(-1).经与相关标准进行比较,浙江省食用菌重金属含量处于相对较低的水平.鲜食用菌中平菇与金针菇的4种重金属元素背景值非常相近,并且都处于很低的水平.与鲜食用菌相比,干食用菌重金属含量是鲜食用菌的4.9～7.1倍.蘑菇的铅、汞、砷含量明显高于其他食用菌,与鲜食用菌平均值比较,铅高出91.0%、汞高出322.2%,砷高出224.1%;香菇中镉含量明显高于其他品种食用菌,高出鲜食用菌平均值238.9%.蘑菇的铅、汞、砷和香菇的镉含量在生产栽培中要得到特别关注,应作为质量安全控制的重点. 相似文献
16.
17.
18.
标准是经济活动和社会发展的技术支撑,是产业健康发展的基础。标准引领产业创新发展。中国是世界上竹标准数量最多、体系最完善的国家,竹标准数量占世界竹标准的90%以上。国际标准化组织竹藤技术委员会(ISO/ TC 296)秘书处设在中国。加强竹业标准化工作,对于引领竹产业高质量发展、增强中国在世界竹子领域的话语权意义重大。文章分析了中国竹标准的现状、国家标准化工作的顶层设计、竹标准的实施应用以及对国际竹标准的支撑情况,提出了标准引领竹产业发展的建议,以期为加强竹业界的信息交流以及竹相关国家标准和国际标准的制定提供参考。 相似文献
19.