Historical Context

Eight one meter long logs comprising the bole of a single sugar maple tree were left in a pile beside a woodland road in the spring of 1993.  The logs ranged from 5 cm to 12 cm in diameter.  These logs had been weighed in the field and sections (cookies) were removed to determine the mass of the wood and bark in 1993.  The analytical results of the dimension analysis from the 1993 study were available to us in the form of data  recorded by the students for these particular logs in 1993.  Chemical analysis was not done on the wood and bark of the logs when they were first cut.  We do, however, have chemical data for some elements obtained from sugar maples  from Sea Hill (an area within a km of this location) in 1996 and from Hubbard Brook, New Hampshire in 1970.  We have used these data for the comparisons of the changes in nutrient concentrations and content over the 5 years.

Field Work 1998

In the field, eight logs were measured (length, diameter at both ends and middle) and the data was recorded.  The diameter of the logs with bark was measured at both ends of each log and in the middle.  Four of the eight logs (two small, one medium and one large) were brought back to the lab.  These logs were measured and then debarked in the field, as the bark crumbled easily when handled.  The other four logs were left in the field.  However, three cookies were removed from each log and brought back to the lab for analysis.  The bark was not separated from the cookies because cutting the cookies caused the wood to disintegrate and it was impossible to separate the wood from the bark.

Lab Work 1998

Back at the lab, the logs and the bark were weighed and three cookies were then sawn from each log length - one from each end and from the middle of each log.  Both the cookies and the logs were then placed in the oven at 70 degrees Centigrade until dry.  The cookies from the logs left in the field were also placed in the oven at the same temperature.  Samples were removed from the oven at various intervals to weigh in order to determine if the moisture in the samples had been completely eliminated.  The samples remained in the oven for a period of approximately ten days to ensure that the samples were thoroughly dry.

Plant Chemistry 1998

Sample Preparation
In order to obtain a representative sampling of nutrient composition of the sugar maple, three sections of the tree were analyzed.  Three cookies from near the stump (log 8), three cookies from the mid-section (log 5), and three cookies from near the top of the tree (log 3) were examined to determine their chemical makeup.  Oven-dry weight was measured for each cookie and for each log in total.  These samples were put back into the oven, along with each corresponding bark sample to prepare them for the initial stages of chemical analysis.  Because some of the cookies were small and more decomposed than others, no attempt was made to take samples from distinct parts of each cookie.  Therefore, the samples were taken from each cookie were randomly selected from the contents of the bag or drilled from various parts of the cookie.  Before preparation for ashing the subsamples, each cookie and bark sample was oven-dried at 70 degrees for a minimum of 48 hours.

ICP
Step 1
After they were thoroughly dry, samples from each jar were weighed out into crucibles.  First, each empty crucible was given a unique batch and sample number and weighed.  Next, samples of approximately 1 g for wood and .3 g for bark were placed in each crucible.  These samples, weighed to .1 mg, were then placed into dessicators with a blank (empty crucible) and a .3 g sample of NBS apple leaves in each batch (14 crucibles).  All weights were recorded in the long-term permanent data management sheets in Siccama's lab in Greeley.  Crucibles were then removed from dessicators and placed in a muffle furnace set at 500 degrees Centigrade and left overnight to ash.  Each crucible was then re-weighed and recorded.

Step 2
After the samples were weighed and these weights were recorded, several drops of distilled water were added to the fluffy ash in each crucible.  The samples were then dissolved into 8 ml of 6N HNO3.  After the samples were put into solution, the crucibles were placed on a hot plate and simmered for 5 to 10 minutes.  Each crucible was removed once the solution had begun to roil, indicated by a subtle swirling motion.  After it was removed from the hot plate, each sample was filtered through #41 filter paper into a 50 ml volumetric.  Each crucible was thoroughly rinsed twice with distilled water to remove any remaining sample solution.  Each sample was then diluted to a total of 50 ml with distilled water and homogenized by shaking.  The contents of each flask were then poured into 60 ml nalgene plastic bottles and labeled according to the sample number.

Step 3
The concentration of four elements, Ca, P, K, and Mg, in each sample solution was then determined using a Perkin Elmer Optima 3000 Inductively-Coupled Plasmaspectrometer (ICP).  A total of 12 sample solutions were run through the ICP.  The ICP was calibrated before each use by running a blank and samples of known concentrations (10 mg/l and 100 mg/l of each element of interest).  Concentrations of these elements in the sample solutions were recorded and saved in a data-file for analysis.

CHN

The percentages of carbon and nitrogen in rotting maple wood were determined using a CHN analyzer. Each ground, oven-dry sample was processed in the following manner. A quantity (>1gm) was inserted into a metal bullet and weighed. The CHN was calibrated by running 2 blanks and 2 replicates of the standard, rye flour. Two replicates of 12 samples were analyzed. The machine was recalibarated between the forth and fifth sample sets.