Logscaler
01-30-2009, 06:28 PM
There was some discussion on this started over in tubing. I thought I should post my info here.
Abstract
Field measurements were taken of sap sugar content and sap flow volume at various heights in sugar maple trees from March 3, 1995 through March 28, 1995. Sugar content and sap flow volume were correlated to the height of the tap in the tree. Taps were placed at various heights in four trees. Low taps were placed below four feet (1.2m), mid taps placed at approximately ten feet (3.0m), and high taps were placed at twenty plus feet (6.0m) where possible. Flow volumes were found to be inconsistent due to poor weather for the time period. Sap from high taps yielded a higher average sugar content relative to sap from lower placed taps. Due to the sporadic flow of sap (again due to weather conditions), it is unclear whether this higher sugar content would have remained constant for the period.
The numbers:
All trees were large, full crowned, field edge trees.
For the period the higher taps produced an average sugar content of 2.9%. The mid taps produced an average 2.7% and the low taps 2.5%.
The highest overall sugar content reading was 4.7% from a mid tap in tree #1.
The highest reading for high taps was 4.2% from tree #1.
The highest reading for mid taps was 4.7% from tree #1.
The highest reading for low taps was 3.5% from tree # 2.
The lowest reading from low taps was 1.8% from trees 3 and 4.
The lowest reading for mid taps was 1.8% from tree #3.
The lowest reading for high taps was 1.7% from tree #3.
Average sugar content for tree #1 was: high tap = 3.2%, mid tap = 3.6%, low tap = 2.7%.
Average sugar content for tree #2 was: high tap = 3.0%, mid tap = 2.6%, low tap = 2.9%.
Average sugar content for tree #3 was: high tap = 2.5%, mid tap = 2.3%, low tap = 2.4%.
Average sugar content for tree #4 was: high tap = 3.0%, mid tap = 2.1%, low tap = 2.2%.
Sap Volume: average daily volume (in litres – sorry) for the period by tap:
Tree #1: high tap = .37L, mid tap = 1.95L, low tap = 3.67L
Tree #2: high tap = .43L, mid tap = 4.3L, low tap = 7.0L
Tree #3: high tap = .6L, mid tap = 1.6L, low tap = 3.2L
Tree #4: high tap = .35L, mid tap = .133L, low tap = 1.83L
There were numerous days during the period that zero sap was collected from the high taps when the mid and low taps produced sap.
Conclusion: (please note that this is an unpublished undergraduate research project)
Under the proper temperature conditions sugar is constantly supplied to the sap stream. As the sap flows up the tree it is collecting sugar and carrying it up to the twigs. Although a direct relationship between the height of the tap and sugar content has been shown, the higher taps produced a relatively much lower volume. The commercial application of these findings is highly limited. The extremely low comparative volumes of the higher taps would make the tapping of trees at greater than the currently accepted standards not profitable.
Oh – by the way – I did get an “A” on the paper!
Abstract
Field measurements were taken of sap sugar content and sap flow volume at various heights in sugar maple trees from March 3, 1995 through March 28, 1995. Sugar content and sap flow volume were correlated to the height of the tap in the tree. Taps were placed at various heights in four trees. Low taps were placed below four feet (1.2m), mid taps placed at approximately ten feet (3.0m), and high taps were placed at twenty plus feet (6.0m) where possible. Flow volumes were found to be inconsistent due to poor weather for the time period. Sap from high taps yielded a higher average sugar content relative to sap from lower placed taps. Due to the sporadic flow of sap (again due to weather conditions), it is unclear whether this higher sugar content would have remained constant for the period.
The numbers:
All trees were large, full crowned, field edge trees.
For the period the higher taps produced an average sugar content of 2.9%. The mid taps produced an average 2.7% and the low taps 2.5%.
The highest overall sugar content reading was 4.7% from a mid tap in tree #1.
The highest reading for high taps was 4.2% from tree #1.
The highest reading for mid taps was 4.7% from tree #1.
The highest reading for low taps was 3.5% from tree # 2.
The lowest reading from low taps was 1.8% from trees 3 and 4.
The lowest reading for mid taps was 1.8% from tree #3.
The lowest reading for high taps was 1.7% from tree #3.
Average sugar content for tree #1 was: high tap = 3.2%, mid tap = 3.6%, low tap = 2.7%.
Average sugar content for tree #2 was: high tap = 3.0%, mid tap = 2.6%, low tap = 2.9%.
Average sugar content for tree #3 was: high tap = 2.5%, mid tap = 2.3%, low tap = 2.4%.
Average sugar content for tree #4 was: high tap = 3.0%, mid tap = 2.1%, low tap = 2.2%.
Sap Volume: average daily volume (in litres – sorry) for the period by tap:
Tree #1: high tap = .37L, mid tap = 1.95L, low tap = 3.67L
Tree #2: high tap = .43L, mid tap = 4.3L, low tap = 7.0L
Tree #3: high tap = .6L, mid tap = 1.6L, low tap = 3.2L
Tree #4: high tap = .35L, mid tap = .133L, low tap = 1.83L
There were numerous days during the period that zero sap was collected from the high taps when the mid and low taps produced sap.
Conclusion: (please note that this is an unpublished undergraduate research project)
Under the proper temperature conditions sugar is constantly supplied to the sap stream. As the sap flows up the tree it is collecting sugar and carrying it up to the twigs. Although a direct relationship between the height of the tap and sugar content has been shown, the higher taps produced a relatively much lower volume. The commercial application of these findings is highly limited. The extremely low comparative volumes of the higher taps would make the tapping of trees at greater than the currently accepted standards not profitable.
Oh – by the way – I did get an “A” on the paper!