Populus species

Populi nipiraegemmae and Populi tremulae pemmae are the buds of these two Populus species. They are used as expectorants and circulatory stimulants for the treatment of upper respiratory tract infections and rheumatic conditions. 

A characteristic feature of phytochemicals in natural populations is the variation in concentration and profile that is found among different individuals. Extensive work by Lindroth and others has documented such genotype-dependant variation in phenolics in P. tremuloides genotypes. " As mentioned above, high levels of phenolics correlate with increased pest resistance in this system. Comparisons of different Populus species and hybrids have also demonstrated a significant variation in levels and types of phenolic phytochemicals.Further variability is often due to environmental conditions, as aspen plants grown with high... 

Foliage of six hybrid clones of poplar (Populus species) were exposed to simulated rain at various pH levels. The responses of two clones (8 and 327) of poplar were markedly different from those of the other four clones used. In clones 8 and 327, exposure to simulated acid rain resulted in gall-like outgrowths after one or two, 6-min daily exposures (Fig. 6 and 10). The epidermis of the gall and the tissues that surround the gall col-... 

The signals of LCC y-esters can overlap with signals of various y-esters of other types, such as the benzoate, ferulate, and coumarate types. It is difficult to distinguish between them by using only the HSQC NMR method. The HSQC spectra indicate that the pine and birch preparations do not contain these types of ester moieties and, therefore, the quantified y-esters can be attributed to LCC-type moieties exclusively [21]. However, Populus species contain p-benzoates moieties [15,81]. Various non-wood lignins contain ferulate and coumarate derivatives [15,19,59,60]. Therefore, accurate quantification of various types of lignin and LCC y-esters in these species will be more difficult. 

Larvae of the butterfly Papilio glaucus glaucus feed mainly on members of the Magnoliaceae, but rarely survive past the first instar when fed plant material of the genus Populus (Salicaceae). In contrast, larvae of Papilio glaucus canadensis perform well on aspen and other Populus species, but die when fed members of the Magnoliaceae (Lin-droth et al., 1988). The major compounds responsible for the lack of acceptability of Populus species to larvae of Papilio... 

Lindroth, R. L., M. T. S. Hsia, and J. M. Scriber, Seasonal patterns in the phytochemistry of three Populus species, Biochem. Syst. Ecol., 15, 681-686 (1987b). 

Propolis is a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants, mainly from poplar (Populus) species and, to a lesser extent, beech, horse chestnut, birch, and conifer. Bees mix the original propolis with beeswax and (5-glucosidase they secrete during the propolis collection. The resulting material is used by bees to seal holes in the hives, exclude drafts, protect against external invaders, and mummify their carcasses. Propolis has been used extensively in folk medicine for many years, and there is substantial evidence indicating that propolis has antiseptic, antifungal, antibacterial, antiviral, anti-inflammatory, and antioxidant properties [42]. 

In spite of the fact that dihydroxy- and trihydroxybenzene units are very common in more complex plant phenols, they have very rarely been found and, if so, in only small amounts in the free state. Catechol (2) has been found in the bark of two Populus species (53, 130) and resorcinol (3) has been identified in the heartwood of five Moms (46) species as well as in Quercus rubra wood (152).The 4-methylcatechol, which inhibits fungal growth, was isolated in the reaction zone in sapwood of Picea abies attacked by Pomes annosus (133). 

Balm of Gilead buds are the leaf buds collected in tbe spring before they open. Precise source is not certain all above species as well as other Populus species are probably used. 

The dominant species are the spruce (Picea excelsa), the birch (Betula verrucosa, B. pubescens), the aspen (Populus tremula), and the alder (Aims incana). The moss and low bush layer is represented by the blueberry-bush (Vaccinium myrtiilus), hypnic mosses, separate species of cowberry (Vaccinium uliginosum) and flowering plants. The biomass of these Spruce Forest ecosystems reaches 10 ton/ha at the age of 100-150 years (Table 4). 

The particular wood species we chose for this study is aspen (Populus tremuloides), which is plentiful in Canada and in the northern U.S.A. The chemical composition we found to be glucan 53.4%, xylan 14.9%, total carbohydrate 79.0%, lignin 17.1% and extractives 3.8%. We would expect total fermentable sugars of about 56% in this sample of aspen in anhydro form (Timell has reported about 60% in another sample (15)) which upon hydrolysis would yield about 1,250 lb wood sugars per ton of wood (dry basis), from the stoichiometry. Theoretical conversion of this sugar to ethanol would yield 640 lb or 81.1 gallons of anhydrous... 

Salicinum, Salicin, C13H1807, is a glucoside obtained from several species of Salix, the willow, and populus, the poplar, trees of the nat. ord. Salicaceae. It is found also in Gaultheria procum-bens, the wintergreen, nat. ord. Ericaceae and in Betula lenta, the sweet birch, nat. ord. Betulaceae the volatile oils of which, distilled from the leaves of the former and from the bark of the latter, consist almost entirely of methyl salicylate. 

When beavers first colonize a site they begin by harvesting the most palatable species, such as aspen (Populus spp.) or willow (Salix spp.). Over time, they change the vegetation by their selection of trees for food and construction of dams and lodges. Eventually, often only the least preferred conifers are left, and the beavers move to a new area until some of the depleted vegetation has regenerated. Beavers move back in, and the cycle repeats. 

Study the beavers responses to juvenile vs. adult growth forms. Species used will depend on availability. Best are aspen (Populus tremuloides or P. grandidentata) or cottonwood (Populus deltoides). 

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