scholarly journals Variation of Drying Strains between Tangential and Radial Directions in Asian White Birch

Forests ◽  
2016 ◽  
Vol 7 (12) ◽  
pp. 59 ◽  
Author(s):  
Zongying Fu ◽  
Jingyao Zhao ◽  
Yeli Yang ◽  
Yingchun Cai
Keyword(s):  
White Birch

AMMONOLYSIS OF URONIC ESTER GROUPS IN BIRCH XYLAN

1964 ◽  
Vol 42 (11) ◽  
pp. 2434-2439 ◽  
Author(s):  
Paul Y. Wang ◽  
H. I. Bolker ◽  
C. B. Purves
Keyword(s):  
Alkaline Hydrolysis ◽  
Uronic Acid ◽  
Liquid Ammonia ◽  
Treated Wood ◽  
Hot Water ◽  
Amide Nitrogen ◽  
White Birch

Solvent-extracted white birch, kept near 20° in liquid ammonia under pressure for 72 h and then extracted with methanol to remove acetamide, retained 0.25% of amide nitrogen. Extraction of the very finely ground residual wood with hot water yielded 21% as a 4-O-methylglucuronoxylan containing 0.53% of amide nitrogen. Alkaline hydrolysis removed the amide absorption in the infrared and restored the normal xylan spectrum. These results, supported by various control experiments, showed that amide groups in the ammonia-treated wood were derived from lactone or ester groups in the original 4-O-methylglucuronoxylan. Some of the uronic acid groups in the native wood presumably existed as ester crosslinks.

Extractives in Betula celtiberica stemwood and isolation and identification of diarylheptanoids in the hydrophilic extract

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Annika I. Smeds ◽  
René Herrera ◽  
Jani Rahkila ◽  
Stefan M. Willför
Keyword(s):  
Biological Effects ◽  
White Birch ◽  
Exact Mass ◽  
Isolation And Identification ◽  
Low Concentrations ◽  
Acetone Water ◽  
Hydrophilic Extract ◽  
Dry Wood ◽  
Interesting Compound ◽  
Flame Ionisation

Abstract In Betula celtiberica (Iberian white birch) stemwood, the content and composition of lipophilic and hydrophilic extractives were determined; these have not been reported previously in this species. The total gravimetric amount of extractives was 2.2% of dry wood, of which lipophilic extractives accounted for 0.39% and hydrophilic extractives 1.84% (determined by gas chromatography–flame ionisation detection [GC–FID]). The lipophilic extract contained mainly triterpenoids and steroids. The hydrophilic extract (acetone–water 95:5 v v−1) contained mainly sugars, compounds not eluting on GC, and a large number of unidentified compounds, which accounted for 0.87% of dry wood and dominated the extract. The compounds were isolated from the extract by silica column chromatography and further purified. GC–electron impact (EI)-MS of the silylated compounds showed characteristic mass fragments that suggested them to be diarylheptanoids (DAHs). This is an interesting compound group, as many of them have shown a large variety of beneficial biological effects. Of over 80 detected DAHs, the exact mass of 17 compounds was determined by electrospray ionisation-quadrupole-time-of-flight (ESI-QTOF)-MS, and of these, the structure of 11 compounds was elucidated by nuclear magnetic resonance (NMR). One was a meta,para-bridged diphenylether and 10 were meta,meta-bridged biphenyls, of which one, 3,8,9,17-tetrahydroxy-[7,0]-metacyclophane, has not been described previously. Because of low concentrations, 21 DAHs were only tentatively identified, and of these, as many as 17 seem to be previously undescribed compounds.

scholarly journals Elk (Cervus elaphus) Seasonal Habitat Selection in a Heterogeneous Forest Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jesse N. Popp ◽  
David N. C. McGeachy ◽  
Josef Hamr
Keyword(s):  
Habitat Selection ◽  
Cervus Elaphus ◽  
Forest Structure ◽  
Hardwood Forests ◽  
Climatic Conditions ◽  
White Birch ◽  
Balsam Poplar ◽  
Adult Females ◽  
Selection Of ◽  
Future Management

Seasonal habitat selection by the reintroduced Burwash elk population, approximately 30 km south of Sudbury, Ontario, has been analysed in order to assist in the development of future management. Twenty-five adult females were radio-collared and tracked 1–3 times a week for 3 years. The most prominent patterns included selection of intolerant hardwood forests (trembling aspen, white birch, and balsam poplar) during all seasons, while Great Lakes-St. Lawrence pines (white and red pine dominated stands) were used less than expected based on availability for all seasons. The selection patterns are likely associated with seasonal climatic conditions and forage preferences. Because the selection behaviours displayed here varied greatly from other elk habitat studies, it is suggested that managers consider the importance of population-specific habitat studies before developing related strategies.

Sap yields, sugar content, and soluble carbohydrates of saps and syrups of some Canadian birch and maple species

1987 ◽  
Vol 17 (3) ◽  
pp. 263-266 ◽  
Author(s):  
A. R. C. Jones ◽  
I. Alli
Keyword(s):  
Sap Flow ◽  
Sugar Maple ◽  
Sugar Content ◽  
Soluble Carbohydrates ◽  
Red Maple ◽  
White Birch ◽  
Yellow Birch ◽  
Total Carbohydrate ◽  
Total Carbohydrate Content ◽  
Maple Sap

During the spring of 1984 and 1985, white birch (Betulapapyrifera Marsh), sweet birch (B. lenta L), and yellow birch (B. alleghaniensis Britt.) were tapped to determine sap yields and syrup characteristics. These properties were compared with sap yields and syrup produced from sugar maple (Acersaccharum Marsh) and red maple (A. rubrum L). The sap flow seasons were as follows: white birch, 23 days (April 7–29, 1984) and 29 days (April 5 – May 3, 1985); sweet birch, 26 days (1984); yellow birch, 25 days (1985). The sap flow season for the maple species was much earlier than the birch species. Maple sap flow seasons were as follows: sugar maple, 16 days (March 28 – April 12, 1984) and 45 days (March 10 – April 23, 1985); red maple, 44 days (March 11 – April 23, 1985). Sap yields were as follows: white birch, 80.5 L in 1984 (1.0% sap) 51.0 L in 1985 (1.0% sap); sweet birch, 48.0 L in 1984 (0.5% sap); yellow birch, 28.4 L in 1985 (0.5% sap); red maple, 30.6 L in 1985 (2.3% sap); sugar maple, 53.5 L in 1985 (4.5% sap). Sap analyses showed the average total carbohydrate content of all birch saps and all maple saps was 9.2 and 24.5 g/L, respectively. The average sugar contents of the syrups from the birch saps and the maple saps were 302 and 711 g/L, respectively. The average pH of birch and maple saps were similar but the average pH of the syrups obtained from the birch saps was substantially lower than that of the syrups obtained from the maple saps.

Portrait préindustriel dans un contexte de grande variabilité naturelle: une étude de cas dans le centre du Québec (Canada)

2011 ◽  
Vol 87 (05) ◽  
pp. 612-624 ◽  
Author(s):  
Eric Alvarez ◽  
Louis Bélanger ◽  
Louis Archambault ◽  
Frédéric Raulier
Keyword(s):  
Temperate Forest ◽  
Forest Cover ◽  
Sustainable Forest Management ◽  
Forest Succession ◽  
Black Spruce ◽  
Spatial Scales ◽  
White Birch ◽  
Industrial Landscape ◽  
Industrial Forest ◽  
Landscape Scales

Pre-industrial forest cover portrait is a recognized method for establishing the bases of sustainable forest management. However, it is a spatially and temporally dependant concept that should be used with caution in presence of big fires. The objective of the study was to portray the pre-industrial landscape in a mixedwood temperate forest in central Quebec at different spatial scales. The study was based on archival records from a forest company. The pre-industrial forest cover landscape of our study area was mainly composed of mature or old-growth (>100 years) stands and dominated by mixedwood forest stands with intolerant hardwoods. The main tree species were white birch, black spruce and jack pine, three species associated to forest succession after fire in the boreal forest. Considering the great variability caused by the fires and partial knowledge of this variability, for each spatial scale considered, we propose some management targets based on the main pre-industrial characteristics of this forest. To respect the pre-industrial variability, our study suggested that silviculture should be adapted at different landscape scales. Cover types and age class targets should be based on main preindustrial characteristics at each landscape scale analyzed.

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