Abstract
The purpose of this study was to determine the reproducibility of measurements of solar radiation by the degradation of petroleum ether-chlorophyll extracts under oak and pine canopies at 100 evenly spaced points over 5 days. The use of extracts permitted a large number of simultaneous measurements of solar radiation at different heights up to 4-5 m above the ground. Chlorophyll extracts were judged more practical than solarimeters and pyranometers in giving inexpensive simultaneous measurements of light sums over a day in natural vegetation, but less effective in giving reproducible results. On each day, there was a linear relationship over time between changes in absorbance at 660 nm of the chlorophyll extracts and cumulative light sums in g cal/cm2 as measured by an Eppley pyrheliometer. Transmittance of the oak stand was 590% less than that of the pine stand; the oak stand's basal area was 150% greater. Daily average light sums in the pine stand were 33-509 % greater than those in the oak stand, and seedlings, mostly of hardwoods, were twice as dense in the pine stand as in the oak stand. The average range of daily light sums in the pine stand was 2 6 times greater. On three of the five days, light sums at points under pine tree canopies alone were significantly higher than those at points under other combinations of tree, sapling, and large seedling canopies. All species of seedlings showed random distribution in relation to light measurements, except red maple in the pine stand.
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Claims 11
Claim · model-written summary
Chlorophyll extracts allowed many simultaneous radiation measurements at heights up to 4-5 m.
Pinus
QuercusOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The use of extracts permitted a large number of simultaneous measurements of solar radiation at different heights up to 4-5 m above the ground”
e1“under oak and pine canopies”
Claim · model-written summary
Chlorophyll extracts were more practical than solarimeters and pyranometers for inexpensive simultaneous daily light measurements.
- Outcome
- measurements of light sumse0
- Direction
- more practicale0
- Comparator
- solarimeters and pyranometerse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll extracts were judged more practical than solarimeters and pyranometers in giving inexpensive simultaneous measurements of light sums over a day in natural vegetation”
e1“under oak and pine canopies”
Claim · model-written summary
Chlorophyll extracts gave less reproducible results than solarimeters and pyranometers.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll extracts were judged more practical than solarimeters and pyranometers in giving inexpensive simultaneous measurements of light sums over a day in natural vegetation, but less effective in giving reproducible results”
e1“under oak and pine canopies”
Claim · model-written summary
Daily absorbance changes of chlorophyll extracts had a linear relation with pyrheliometer light sums.
- Outcome
- cumulative light sumse0
- Qualifier
- linear relationship over timee0
- Comparator
- changes in absorbance at 660 nme0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On each day, there was a linear relationship over time between changes in absorbance at 660 nm of the chlorophyll extracts and cumulative light sums in g cal/cm2 as measured by an Eppley pyrheliometer”
e1“under oak and pine canopies”
Claim · model-written summary
Oak-stand transmittance was reported as 590% less than pine-stand transmittance.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Transmittance of the oak stand was 590% less than that of the pine stand”
Claim · model-written summary
Oak-stand basal area was 150% greater than pine-stand basal area.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the oak stand's basal area was 150% greater”
e1“than that of the pine stand”
Claim · model-written summary
Daily average light sums in pine stands were 33-509 % greater than in oak stands.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Daily average light sums in the pine stand were 33-509 % greater than those in the oak stand”
Claim · model-written summary
Seedlings, mostly hardwoods, were twice as dense in pine stands as in oak stands.
Verbatim
e0“seedlings, mostly of hardwoods, were twice as dense in the pine stand as in the oak stand”
Claim · model-written summary
The average range of daily light sums was 2 6 times greater in pine stands.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average range of daily light sums in the pine stand was 2 6 times greater”
Claim · model-written summary
On three of five days, light sums under pine tree canopies alone exceeded those under other canopy combinations.
- Outcome
- light sumse0
- Direction
- highere0
- Qualifier
- On three of the five dayse0
- Comparator
- other combinations of tree, sapling, and large seedling canopiese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“On three of the five days, light sums at points under pine tree canopies alone were significantly higher than those at points under other combinations of tree, sapling, and large seedling canopies”
Claim · model-written summary
Seedling species showed random distributions with respect to measured light, except red maple in the pine stand.
- Taxon
- seedlingse0
- Organ / stage
- seedlingse0
- Outcome
- random distributione0
- Qualifier
- except red maple in the pine stande0
- Comparator
- light measurementse0
Not reportedDirection
Verbatim
e0“All species of seedlings showed random distribution in relation to light measurements, except red maple in the pine stand”