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1.) Source of material: Saltonstall Ridge,
East Haven, CT
2.a) Field collection of tissue samples: We
collected and dissected six Ailanthus trees of different
sizes. We removed branches and twigs and saved them
separately. Boles were cut into two meter lengths. We field
weighed all parts of all fresh-cut trees (wet) on hanging
balance. We cut 5-10 cm thick "cookie" sections from every
other log of the four largest trees.
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2.b) Processing in laboratory:
bole section cookies measured, bark removed from
cookies, wood remeasured. Bark weighed wet. Wood
weighed wet. Twigs, branches, bark, cookies all
dried at 80° C until no more water weight lost
(approximately two weeks.)
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Mariana and Anne
weighing and debarking cookies.
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2.c) Representative parts
ground up using power drill and Wiley
mill:
Wood- 5/8" bit drilled on cookies.
Initial drill dust discarded. Saved clean dust from
4-5 drillings avoiding edge and pith. Redried at
80° C.
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Bark- Cookie bark from four
biggest trees separately ground in a Wiley mill,
and redried.
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Branches & Twigs -
Representative parts (size proportional sampling)
from three branches of sizes ranging from the
smallest to largest separately ground as either
twigs or branch wood in mill, and redried.
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Annie grinding samples in the Wiley
mill.
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2.d) Ashing: Small amounts, (one
gram and less) of duplicate samples weighed out in
crucibles, also one quad., two apple leaf standards
and two blanks all ashed at 500° C,
reweighed.
2.e) Putting ash into solution: To
prepare samples to run through analyzer, ash was
digested in 8 ml of 6 N
HNO3 , heated to
simmering, (100° C.), filtered and diluted to
50 mls (volumetric flask) with distilled de-ionized
(DDI) water.
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Anne weighing ash
samples.
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3.) I. C. P.: The concentrations of 7
elements (Ca, Mg -- etc) in the extraced solution were
determined with an ICP - Inductively coupled plasma-emission
spectrophotometer.
4.) Calculations: The objective of this
process is to obtain the elemental concentration in the
original plant tissues. To do this the ICP results give the
concentration per ml of solution in the extract. To convert
this to a concentration in the dry sample one must first
multiply the ICP concentration by 50(ml) and then divide
this result by the sample weight. The ICP data is in ug/ml
and the sample weight is in grams. making the calculations
gives ug/of element per gram of dry sample.
Example: (7ug of Ca/ ml) x (4.9 g of
sample) = 34.3 ug of Ca /g of dry sample.
5.) Problems:
Data Management: Data sheets with wet
and dry weights for branches and their respective twigs
were not completed consistently in the field. Ditto dry
samples in the lab. We had to extrapolate from those
branches and twigs for which we did have weights, that
twigs usually represent approximately 10% of the total
dry weight of the average Ailanthus branch. We
could test this by collecting more branches in the field
and obtaining wet and dry weights for branches and their
twigs.
Sample Preparation: Grinding once
through the Wiley produces a lumpy heterogeneous product
unlike the fine-powdered apple leaf standard. We weighed
out such tiny amounts of sample from the randomly mixed
mill grindings, that some 0.3g bark duplicates varied a
great deal in estimated nutrient content.
I. C. P.: Calibration blank and three
calibration standards of 1,10, and 100 mg/L should have
been followed by an extra calibration blank or been timed
for a longer rinse cycle or both. Our sample blank which
followed the 100 mg/L calib. blank was greatly influenced
by it in contrast to the blank run among our
samples.
Samples: The 0.3 gram samples of bark
still seemed to be too concentrated for an accurate
reading. In addition to finer grinding in another mill,
further dilution may be called for.
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