scholarly journals Differences in carbon isotope leaf‐to‐phloem fractionation and mixing patterns along a vertical gradient in mature European beech and Douglas fir

2019 ◽  
Vol 222 (4) ◽  
pp. 1803-1815 ◽  
Author(s):  
Rebekka Bögelein ◽  
Marco M. Lehmann ◽  
Frank M. Thomas
Keyword(s):  
Carbon Isotope ◽  
European Beech ◽  
Vertical Gradient ◽  
Douglas Fir ◽  
Mixing Patterns

Lignin and cellulose concentrations in roots of Douglas fir and European beech of different diameter classes and soil depths

Trees ◽  
2013 ◽  
Vol 28 (1) ◽  
pp. 309-315 ◽  
Author(s):  
Frank M. Thomas ◽  
Florian Molitor ◽  
Willy Werner
Keyword(s):  
European Beech ◽  
Douglas Fir ◽  
Diameter Classes

scholarly journals Planting mixed forests of European beech and conifers: Variations in microbial responses with site conditions

2020 ◽  
Author(s):  
Jing-Zhong Lu ◽  
Stefan Scheu
Keyword(s):  
Microbial Communities ◽  
Environmental Conditions ◽  
Tree Species ◽  
Soil Microorganisms ◽  
European Beech ◽  
Douglas Fir ◽  
Site Conditions ◽  
Forest Types ◽  
Beech Forests

AbstractTree - soil interactions depend on environmental context. Plantations of trees may impact soil microorganisms more strongly under unfavorable environmental conditions, compromising long-term ecosystem services. To contextually understand the effects of tree species composition on soil microorganisms, we quantified structural and functional responses of soil microorganisms to forest types across environmental gradients using substrate-induced respiration and phospholipid fatty acid analyses. Five forest types were studied including pure stands of native European beech (Fagus sylvatica), range expanding Norway spruce (Picea abies), and non-native Douglas-fir (Pseudotsuga menziesii), as well as the two conifer - beech mixtures. We found that microbial functioning strongly depends on environmental conditions, in particular on soil nutrients. At nutrient-poor sites, both pure and mixed coniferous forests, but especially Douglas-fir forests, stressed soil microorganisms compared to beech forests. By contrast, microbial structure and functional indicators in beech forests varied little with site conditions, likely because beech provided high amounts of root-derived resources for microbial growth. The results indicate that, at nutrient-poor sites, long-term effects of planting exotic Douglas-fir on ecosystem functioning need further attention, but planting Douglas-fir at nutrient-rich sites may be of little concern from the perspective of microbial communities. Overall, the results point to the importance of root-derived resources in determining the structure and functioning of soil microbial communities, and document the sensitivity of soil microorganisms to planting tree species that may differ in the provisioning of these resources.

Canopy structure in Late Cretaceous and Paleocene forests as reconstructed from carbon isotope analyses of fossil leaves

Geology ◽  
2019 ◽  
Vol 47 (10) ◽  
pp. 977-981 ◽  
Author(s):  
Heather V. Graham ◽  
Fabiany Herrera ◽  
Carlos Jaramillo ◽  
Scott L. Wing ◽  
Katherine H. Freeman
Keyword(s):  
Carbon Isotope ◽  
Late Cretaceous ◽  
Isotope Composition ◽  
Canopy Structure ◽  
Lacustrine Sediments ◽  
Vertical Gradient ◽  
Time Period ◽  
Open Canopy ◽  
Canopy Effect ◽  
Closed Canopy

Abstract While modern forests have their origin in the diversification and expansion of angiosperms in the Late Cretaceous and early Cenozoic, it is unclear whether the rise of closed-canopy tropical rainforests preceded or followed the end-Cretaceous extinction. The “canopy effect” is a strong vertical gradient in the carbon isotope (δ13C) composition of leaves in modern closed-canopy forests that could serve as a proxy signature for canopy structure in ancient forests. To test this, we report measurements of the carbon isotope composition of nearly 200 fossil angiosperm leaves from two localities in the Paleocene Cerrejón Formation and one locality in the Maastrichtian Guaduas Formation of Colombia. Leaves from one Cerrejón fossil assemblage deposited in a small fluvial channel exhibited a 6.3‰ range in δ13C, consistent with a closed-canopy forest. Carbon isotope values from lacustrine sediments in the Cerrejón Formation had a range of 3.3‰, consistent with vegetation along a lake edge. An even-narrower range of δ13C values (2.7‰) was observed for a leaf assemblage recovered from the Cretaceous Guaduas Formation, and suggests vegetation with an open canopy structure. Carbon isotope fractionation by Late Cretaceous and early Paleogene leaves was in all cases similar to that by modern relatives, consistent with estimates of low atmospheric CO2 during this time period. This study confirms other lines of evidence suggesting that closed-canopy forests in tropical South America existed by the late Paleocene, and fails to find isotopic evidence for a closed-canopy forest in the Cretaceous.

Comparison of ecosystem water-use efficiency among Douglas-fir forest, aspen forest and grassland using eddy covariance and carbon isotope techniques

2006 ◽  
Vol 12 (2) ◽  
pp. 294-310 ◽  
Author(s):  
STÉPHANE PONTON ◽  
LAWRENCE B. FLANAGAN ◽  
KARRIN P. ALSTAD ◽  
BRUCE G. JOHNSON ◽  
KAI MORGENSTERN ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Carbon Isotope ◽  
Eddy Covariance ◽  
Water Use ◽  
Douglas Fir ◽  
Isotope Techniques ◽  
Ecosystem Water Use Efficiency ◽  
Use Efficiency ◽  
Aspen Forest
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