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Nitrogen mineralization in forest floors of three tree species on the same site : the role of litter quality Thomas, Keith Douglas
Abstract
Forest floor samples from a 25-year-old plantation of three tree species [Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), and paper birch {Betula papyrifera Marsh.)] growing on the same site were incubated (aerobically) in the laboratory for 29 d. Net N mineralization per g of dry matter in the forest floors of Douglas-fir (144.1 pg/g) was significantly greater than either birch (64.2 pg/g) or lodgepole pine (49.1 pg/g). Initial NH₄-N was highest in the forest floor of Douglas-fir (26.5 pg/g), followed by paper birch (9.8 pg/g) and lodgepole pine (3.5 pg/g). Initial N0₃-N was low for all three species and increased very slightly during the incubation, suggesting that ammonification was the dominant process. N mineralized per unit mass of N in the forest floors of Douglas-fir (6.6 ug/g N) was significantly greater than either birch (3.3 ug/g N) or lodgepole pine (2.9 ug/g N). There were no significant differences among the three species in rates of CO₂-C mineralization in forest floors during the 29 d aerobic incubation. Nitrogen concentrations in the forest floors of the three species differed significantly: Douglas-fir had the greatest % N (2.09), lodgepole pine the least (1.65), and birch was intermediate (1.85). Percent total N and C/N of the forest floor were strongly correlated (r²= 0.81 and r²= 0.54, respectively) with net N mineralization, showing a clear species separation. The litter of Douglas-fir had the highest lignin/N and C/N ratios, and mineralized the most N during the incubation, whereas the litter of paper birch had the lowest lignin/N and C/N ratios yet mineralized the second lowest amount of N. Net N mineralization in the forest floor was not correlated with either lignin/N or C/N of the foliar litter, suggesting that this index does not have widespread applicability to all litter types.
Item Metadata
Title |
Nitrogen mineralization in forest floors of three tree species on the same site : the role of litter quality
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1997
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Description |
Forest floor samples from a 25-year-old plantation of three tree species [Douglas-fir
(Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), and paper birch {Betula papyrifera Marsh.)] growing on the same site were incubated (aerobically) in the laboratory for 29 d. Net N mineralization per g of dry matter in the forest floors of Douglas-fir (144.1 pg/g) was significantly greater than either birch (64.2 pg/g) or lodgepole pine (49.1 pg/g). Initial NH₄-N was highest in the forest floor of
Douglas-fir (26.5 pg/g), followed by paper birch (9.8 pg/g) and lodgepole pine (3.5 pg/g). Initial N0₃-N was low for all three species and increased very slightly during the incubation, suggesting that ammonification was the dominant process. N mineralized per unit mass of N in the forest floors of Douglas-fir (6.6 ug/g N) was significantly greater than either birch (3.3
ug/g N) or lodgepole pine (2.9 ug/g N). There were no significant differences among the three species in rates of CO₂-C mineralization in forest floors during the 29 d aerobic incubation. Nitrogen concentrations in the forest floors of the three species differed significantly: Douglas-fir had the greatest % N (2.09), lodgepole pine the least (1.65), and
birch was intermediate (1.85). Percent total N and C/N of the forest floor were strongly
correlated (r²= 0.81 and r²= 0.54, respectively) with net N mineralization, showing a clear species separation. The litter of Douglas-fir had the highest lignin/N and C/N ratios, and mineralized the most N during the incubation, whereas the litter of paper birch had the lowest
lignin/N and C/N ratios yet mineralized the second lowest amount of N. Net N
mineralization in the forest floor was not correlated with either lignin/N or C/N of the foliar litter, suggesting that this index does not have widespread applicability to all litter types.
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Extent |
4531925 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-03-24
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0075281
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1997-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.