The R. R. Reynolds Research Natural Area in Southeastern Arkansas

The R. R. Reynolds Research Natural Area is a 32-ha pine-hardwood forest in southeastern Arkansas, U.S.A., that originated from diameter-limit cutting of the virgin forest before 1915. In 1935, these 32 ha were reserved from timber management. Between 1937 and 1993, eight inventories were taken of all living trees > 9-cm DBH, using 2.5-cm DBH classes within three species groups: Pinus spp., Quercus spp., and other hardwoods. In 1994, all standing dead snags of pines and hardwoods > 9-cm DBH were inventoried by 2.5-cm DBH classes. During 56 years, thc overstory pine-hardwood ratio remained stable in terms of relative basal area, but pine density decreased with a commensurate increase in hardwood density. In 1993, pines represented 63% of basal area but only 23% of stem density. Just before the 1993 inventory, a pine bark-beetle infestation developed on the area, and within one year the pines lost about 2.5 m2/ha in basal area and had 180% more snags than were contributed by hardwoods. The overstory pine component is decreasing in density as a result of natural senescence and the allogenic effects of bark beetles. Hardwood species are expected to eventually dominate the forest because shade-intolerant pine regeneration will not develop to maturity beneath the closed hardwood canopy which can be altered only by catastrophic natural disturbances or anthropogenic intervention.     

Kronenabschu?, D. R. P. 424112

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Oberregierungsrat i. R. Professor Dr. Karl Braun

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Dr. M. Pfeil,Rönigl. Preub. Ceh. Oberforftrath,Profeffor und Direftor der R. Jorftafademie ju Reuftadt-Qbersmalde

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毛棉杜鹃和刺毛杜鹃在广州的生长特性研究

毛棉杜鹃 Rhododendron moulmainense 和刺毛杜鹃 R.championae 分布于我国长江以南海拔500～1500 m 的灌丛或疏林,是观赏价值较高的野生观花树木,但极少在城市园林中应用。文章比较研究了毛棉杜鹃和刺毛杜鹃在广州低海拔地区全阳与林下生境的生长表现与物候特点。结果表明：两种杜鹃花属植物在全阳坡地都有较高成活率,能正常开花结果,但夏季生长不良。林下生长的植株表现良好,但未见开花,反映了光照条件是两种植物花芽分化的重要条件。综合比较,毛棉杜鹃在广州的观赏效果和适应性要优于刺毛杜鹃。     

Residue Reviews / Rückstands-Berichte.

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我国红掌发展现状和存在问题浅议

简介我国红掌种植的发展现状;分析其栽培环境、产品质量、生产成本方面存在的问题,提出促进红掌产业发展的建议。     

Artificial hybridization between Robinia pseudoacacia L. and R. pseudoacacia var. monophylla Carr.

Results regarding artificial cross- and self-pollination betweenRobinia pseudoacacia L. and R. pseudoacacia var. monophyllaCarr. are reported. Parental clones involved in a diallel matingscheme were selected according to leaf type phenotype and included(1) single-leaf type, (2) 25-leaf type, (3) three-leaf typeand (4) common Robinia. Artificial pollination proved to bea difficult and delicate procedure. A total of 33 pollinationswere made that resulted in the formation of 84 pods, of which24 developed fully and produced 65 seeds. Fifteen seeds weregerminated, resulting in the production of two putative fertilehybrids. The success of hybridization was assessed by geneticmarkers, while parental clones and hybrid progeny were assignedmultilocus genotypes. The mode of inheritance of the leaf typetrait was studied in open-pollinated families where the monophyllatype was the maternal parent. The study indicated that leaftype in the monophylla variety may be associated with majorgene effects.     

Tropical Timber Trade Flows in P.R. China

The historical transition of timber distribution pattern in China was presented firstly with main parts of timber flows in China, which included timber markets, timber transport system and regulations of timber transport. Based on the overview on tropical timber flows in China, the trade flows of tropical timber from production and imports of tropical timber to export of tropical timber products were analyzed by vivid illustrations. At the same time, problems in timber trade flows in China were analysed in the end.     

156名共和国部长为首都添绿

3月29日上午,阳光灿烂,春光明媚。“建绿色家园———共和国部长义务植树”活动在京隆重举行。全国绿化委员会副主任、国家林业局局长周生贤,国家林业局副局长李育材,国家林业局党组成员、中央纪委驻国家林业局纪检组组长杨继平,国家林业局副局长祝列克等与中央各部门、国务院各部委、首都绿化委员会共计156名部长在北京市海淀区四季青乡义务植树。在义务植树现场,国家林业局副局长祝列克对记者说:“全民开展义务植树运动22年来,全国义务植树人数累计达82.8亿人次,植树398.4亿株。在全民义务植树运动的推动下,我国国土绿化质量显著提高,森林…     

红千层扦插育苗试验

应用正交试验方法,探讨了红千层不同扦插季节、不同基质、生根剂不同浓度和浸泡时间对扦插成活率的影响。结果表明:在秋季选用混合基质(黄心土∶粗河沙∶草木灰=1∶1∶1),采用ABT1号生根粉200 mg·kg-1浸泡2 h,扦插生根率最高。     

Qtmas über die R. bader. Forftmärter

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