Papyriferic acid: a triterpenoid from Alaskan paper birch

1981 ◽  
Vol 46 (22) ◽  
pp. 4576-4578 ◽  
Author(s):  
Paul B. Reichardt
Keyword(s):  
1990 ◽  
Vol 20 (9) ◽  
pp. 1479-1484 ◽  
Author(s):  
F. A. Bazzaz ◽  
J. S. Coleman ◽  
S. R. Morse

We examined how elevated CO2 affected the growth of seven co-occurring tree species: American beech (Fagusgrandifolia Ehrh.), paper birch (Betulapapyrifera Marsh.), black cherry (Prunusserotina Ehrh.), white pine (Pinusstrobus L.), red maple (Acerrubrum L.), sugar maple (Acersaccharum Marsh.), and eastern hemlock (Tsugacanadensis (L.) Carr). We also tested whether the degree of shade tolerance of species and the age of seedlings affected plant responses to enhanced CO2 levels. Seedlings that were at least 1 year old, for all species except beech, were removed while dormant from Harvard Forest, Petersham, Massachusetts. Seeds of red maple and paper birch were obtained from parent trees at Harvard Forest, and seeds of American beech were obtained from a population of beeches in Nova Scotia. Seedlings and transplants were grown in one of four plant growth chambers for 60 d (beech, paper birch, red maple, black cherry) or 100 d (white pine, hemlock, sugar maple) under CO2 levels of 400 or 700 μL•L−1. Plants were then harvested for biomass and growth determinations. The results showed that the biomass of beech, paper birch, black cherry, sugar maple, and hemlock significantly increased in elevated CO2, but the biomass of red maple and white pine only marginally increased in these conditions. Furthermore, there were large differences in the magnitude of growth enhancement by increased levels of CO2 between species, so it seems reasonable to predict that one consequence of rising levels of CO2 may be to increase the competitive ability of some species relative to others. Additionally, the three species exhibiting the largest increase in growth with increased CO2 concentrations were the shade-tolerant species (i.e., beech, sugar maple, and hemlock). Thus, elevated CO2 levels may enhance the growth of relatively shade-tolerant forest trees to a greater extent than growth of shade-intolerant trees, at least under the light and nutrient conditions of this experiment. We found no evidence to suggest that the age of tree seedlings greatly affected their response to elevated CO2 concentrations.


2021 ◽  
Author(s):  
Patrick F. Sullivan ◽  
Annalis H. Brownlee ◽  
Sarah B.Z. Ellison ◽  
Sean M.P. Cahoon

1994 ◽  
Vol 19 (1) ◽  
pp. 6-10 ◽  
Author(s):  
MARC-ANDRÉ MARTIN ◽  
NAOMI CAPPUCCINO ◽  
DOMINIC DUCHARME
Keyword(s):  

2020 ◽  
Vol 153 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Susanne Kühnholz ◽  
Regine Gries ◽  
John H. Borden

AbstractPorapak Q-captured volatiles from both sexes of Trypodendron betulae Swaine (Coleoptera: Curculionidae: Scolytinae) excised from newly attacked logs of paper birch, Betula papyrifera Marshall (Betulaceae), as well as volatiles from unattacked birch logs, were analysed by coupled gas chromatographic electroantennographic detection analysis. Active compounds were identified by gas chromatographic mass spectroscopy. The enantiomeric ratio of 6-ethenyl-2,2,6-trimethyloxan-3-ol (linalool oxide pyranoid) was determined using a Cyclodex B column. Field-trapping experiments disclosed that the female-produced aggregation pheromone of T. betulae is a blend of the (3S,6R)-trans- and (3R,6R)-cis-linalool oxide pyranoid. Trap catches were synergistically increased when the pheromone was combined with both the host volatile ethanol and with conophthorin, which was found in female beetles as well as host volatiles. Use of linalool oxide pyranoid reproductively isolates T. betulae from sympatric Trypodendron Stephens species for which only (+)-lineatin has been identified as an aggregation pheromone.


1990 ◽  
Vol 7 (1) ◽  
pp. 17-19 ◽  
Author(s):  
Ron E. Wall

Abstract Cultures of the fungus Chondrostereum purpureum (Fr.)Pouzar were applied to cut surfaces of hardwood stumps immediately after the trees were felled in late spring and summer and the stumps monitored for fungus infection and adventitious sprouting during the ensuing 2 years. Hardwood species inoculated were red maple, sugar maple, yellow birch, paper birch, pin cherry, trembling aspen, and beech. The fungus was applied as wheat bran cultures in a mineral oil slurry or by inverting petri dish cultures on the stump. All treatments resulted in development of sporophores of the fungus on the stump within 2 years and a concomitant reduction, as compared to the uninoculated controls, of the number of stump sprouts. The speed of stump invasion by the fungus and reduction of sprouting varied both among and within species. The feasibility of using this fungus as a biological control of regrowth after stand cleaning is discussed. North. J. Appl. For. 7(1):17-19, March 1990.


1989 ◽  
Vol 19 (12) ◽  
pp. 1648-1650 ◽  
Author(s):  
Elizabeth Anne France ◽  
Dan Binkley ◽  
David Valentine

After 27 years of stand development, the accumulated forest floor under replicated plots of white pine (Pinusstrobus L.), white spruce (Piceaglauca (Moench) Voss), paper birch (Betulapapyrifera Marsh.), and silver maple (Acersaccharinum L.) ranged from 240 g/m2 under maple to 3680 g/m2 under white pine. Forest floor pH ranged from a low under maple of 3.7 to a high under white spruce of 5.9. No significant differences were found in pH in 0–15 cm depth mineral soil; however, substantial differences in the acid neutralization capacities were evident among species, with soils under maple showing the lowest capacity to resist further acidification.


2002 ◽  
Vol 32 (5) ◽  
pp. 757-767 ◽  
Author(s):  
John Yarie ◽  
Sharon Billings

Forest biomass, rates of production, and carbon dynamics are a function of climate, plant species present, and the structure of the soil organic and mineral layers. Inventory data from the U.S. Forest Service (USFS) Inventory Analysis Unit was used to develop estimates of the land area represented by the major overstory species at various age-classes. The CENTURY model was then used to develop an estimate of carbon dynamics throughout the age sequence of forest development for the major ecosystem types. The estimated boreal forest area in Alaska, based on USFS inventory data is 17 244 098 ha. The total aboveground biomass within the Alaska boreal forest was estimated to be 815 330 000 Mg. The CENTURY model estimated maximum net ecosystem production (NEP) at 137, 88, 152, 99, and 65 g·m–2·year–1 for quaking aspen (Populus tremuloides Michx.), paper birch (Betula papyrifera Marsh.), balsam poplar (Populus balsamifera L.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) BSP) forest stands, respectively. These values were predicted at stand ages of 80, 60, 41, 68, and 100 years, respectively. The minimum values of NEP for aspen, paper birch, balsam poplar, white spruce, and black spruce were –171, –166, –240, –300, and –61 g·m–2·year–1 at the ages of 1, 1, 1, 1, and 12, respectively. NEP became positive at the ages of 14, 19, 16, 13, and 34 for aspen, birch, balsam poplar, white spruce, and black spruce ecosystems, respectively. A 5°C increase in mean annual temperature resulted in a higher amount of predicted production and decomposition in all ecosystems, resulting in an increase of NEP. We estimate that the current vegetation absorbs approximately 9.65 Tg of carbon per year within the boreal forest of the state. If there is a 5°C increase in the mean annual temperature with no change in precipitation we estimated that NEP for the boreal forest in Alaska would increase to 16.95 Tg of carbon per year.


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