Changes in composition, structure and aboveground biomass over seventy-six years (1930-2006) in the Black Rock Forest, Hudson Highlands, southeastern New York State

We sought to quantify changes in tree species composition, forest structure and aboveground forest biomass (AGB) over 76 years (1930-2006) in the deciduous Black Rock Forest in southeastern New York, USA. We used data from periodic forest inventories, published floras and a set of eight long-term plots, along with species-specific allometric equations to estimate AGB and carbon content. Between the early 1930s and 2000, three species were extirpated from the forest (American elm (Ulmus americana L.), paper birch (Betula papyrifera Marsh.) and black spruce (Picea mariana (nigra) (Mill.) BSP)) and seven species invaded the forest (non-natives tree-of-heaven (Ailanthus altissima (Mill.) Swingle) and white poplar (Populus alba L.) and native, generally southerly distributed, southern catalpa (Catalpa bignonioides Walt.), cockspur hawthorn (Crataegus crus-galli L.), red mulberry (Morus rubra L.), eastern cottonwood (Populus deltoides Bartr.) and slippery elm (Ulmus rubra Muhl.)). Forest canopy was dominated by red oak and chestnut oak, but the understory tree community changed substantially from mixed oak-maple to red maple-black birch. Density decreased from an average of 1500 to 735 trees ha(-1), whereas basal area doubled from less than 15 m(2) ha(-1) to almost 30 m(2) ha(-1) by 2000. Forest-wide mean AGB from inventory data increased from about 71 Mg ha(-1) in 1930 to about 145 Mg ha(-1) in 1985, and mean AGB on the long-term plots increased from 75 Mg ha(-1) in 1936 to 218 Mg ha(-1) in 1998. Over 76 years, red oak (Quercus rubra L.) canopy trees stored carbon at about twice the rate of similar-sized canopy trees of other species. However, there has been a significant loss of live tree biomass as a result of canopy tree mortality since 1999. Important constraints on long-term biomass increment have included insect outbreaks and droughts.     

Kritisches zu: „PETZSCH,H. (1964): Kritische Feststellungen zum Tollwut (Lyssa,Rabies) - Problem“

Ohne Zusammenfassung     

Anti-inflammatory,cyclooxygenase (COX)-2, COX-1 inhibitory and antioxidant effects of Dysophylla stellata Benth.

The n-hexane and ethyl acetate extracts of whole plants of Dysophylla stellata significantly inhibited edema when applied topically at doses of 0.5 and 1 mg/ear in TPA-induced ear edema assay in mice. Further, both the extracts were evaluated for COX-1 and COX-2 inhibitory activities and showed 85.42 and 57.38%; and 71.79 and 89.27% inhibition at 50 µg/ml, respectively. Chromones (1 and 2) present in these extracts could be responsible for their COX-1 and COX-2 inhibitory and anti-inflammatory activities. The ethyl acetate extract showed antioxidant activity in DPPH and ABTS radical scavenging assay where as n-hexane extract found to be inactive.     

SZW(S)10-2.5-M型废料锅炉的研制

随着木材工业的发展,我国木材综合利用企业生产能力达到年产6 0×104～1 0×105 企业不断增多,在建厂初期企业就考虑到木材综合利用原料中有10%～20%的废料(腐朽木、树皮、砂光粉等)是不能利用的废弃物,如何利用这部分废料减轻环境污染,企业的首选方法是利用废料作为燃料使用,这样既解决了废料的污染问题,又节约了企业燃料费支出,企业可在节约燃料费上得到经济效益。木材加工企业购进及改造废料锅炉应根据生产中产生的废料量确定锅炉的容量,根据废料的种类确定锅炉的燃烧方式。1木材加工企业废料量中密度纤维板厂、刨花板厂等木材加工企业…     

Dr. L. G. E. Kalshoven (1892-1970) zum Gedächtnis

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N,N′-二（对硝基苯基）-2,2-′（对苯二氧基）二乙酰胺的合成、结构及计算

以对硝基苯基氯乙酰胺和对苯二酚为原料,在丙酮溶液中反应合成了N,N′-二(对硝基苯基)-2,2-′(对苯二氧基)二乙酰胺.在室温下采用自然扩散溶剂DM F和乙醇混合溶液(1∶20,体积分数)得到了适合于X射线衍射分析的单晶体.依据晶体结构数据建立了分子结构模型,并利用量子化学半经验PM 3方法进行结构优化计算和频率分析.M u lliken电荷布居分析表明分子中醚氧原子和羰基氧原子上都带有大量负电荷,并且与分子内的氢原子之间有氢键作用.