06 factor influence birch sap
TRANSCRIPT
Factors Influencing Birch Sap Production
in Alaskan Birch (Betula neoalaskana
Sarg.)
Kimberley Anne C. Maher
UAF SNRAS
Everything you want to know
Korolyak, I.S. and R.I. Tomchuk. 1971. [Intensifyting sap extraction from birch trees]. Lesnoe Khozyaistvo. 5:34-36.
Mednikov, F.A. 1977. [Conference on the tapping of broadleaved species and processing the sap.]. Lesnoi Zhurnal. 6:162-3.
Outline•Birch as a non-timber forest resource•Sap use in Alaska and elsewhere•Previous research
- Factors influencing sap production- Consequences to the tree from tapping
•Research conducted in Alaska•Future directions for research in Alaska
Betula neoalaskana Sargent
•Formerly referred to as B. resinifera Regel•A Beringian species—most closely related to Asian species•Diploid
Distribution of
Source: Flora of North America 1993+
B. papyrifera MarshallB. neoalaskana
Non-timber Forest Products“all forest products except timber”
• Resins • Oils• Leaves • Bark
• Plants other than trees• Fungi• Animals or animal products
Birch as a NTFP
Birch Sap
• Harvested in spring• Similar to maple sap• Consumed as a tonic or processed
into syrup
Birch sap harvest in Alaska• Main commercial use is to process into
birch syrup• 1992 Producers formed the Alaska Birch
Syrupmakers’ Association (ABSA)
ABSA• “Coopertition” amongst member birch syrup
producers • Created a “Best Practices”
guide for tapping and syrup production
• Information and sales booth at Palmer State Fair
• Would like to develop syrup grading standards
ABSA Best Practices for producing high quality birch syrup
• Tree tapping• Sap collection• Sap storage• Syrup production– reverse
osmosis• Syrup production– evaporator• Syrup finishing
Growth of the Alaska Birch Syrup Industry
0123
4567
1989 1992 1995 1998 2001
year of syrup production
num
ber o
f com
pani
es
invo
lved
in s
yrup
po
rduc
tion
ABFC 2005
Alaska syrup production
Year Number of companies producing
Estimated gallons of
syrup produced
2001 6 1400
2005 4 1500
ABFC 2005; Maher et al. 2005
Birch sap utilization elsewhere
Three birch syrup producers in Canada (2 in British Columbia; 1 in Yukon)
Birch sap harvested, sold, and drank as health tonic in many Northern countries
Birch sap tonic
Adapted from Terazawa 1995
Japan Korea China Finland Russia
Hypertension X X XUrinary problems X X X XGout X X X XDecreased work capacity X X X XGastritis X X X XKidney problem X X XScurvey X X X
Traditional medicine used in Northern countries
Terazawa 1995
Birch sap beverages
“Birch sap with sugar” contains11.5 % sugar and 0.4 % citric acid (Tomchuk et al. 1973)
“Forest drink” contains concentrated birch sap with cranberry juice (Telishevskyj 1970)
Harvesting birch sap increases the value of a stand
• Tapping birch for 5-10 years before harvesting the trees can increase profit several times over the price of wood alone (Tomchuk et al. 1973)
• Profit from natural (fresh?) sap is 2 to 3 times that of the wood while the profit from preserved sap is 7 times that of the wood (Telisevskij 1970)
Factors affecting sap yields
• Sap yields were virtually independent of tree age but were directly proportional to tree diameter (Davidov 1979)
R2 = 0.9817
R2 = 0.9708
0
20
40
60
80
100
120
140
160
180
200
0 20 40 60 80
tree diameter (cm)
avera
ge p
rod
ucti
vit
y (
lite
rs)
B. platyphylla
B. costata
Tagiltsev et al 2005
Average sap productivity of birch species in Russian Far East
Factors affecting sap yields
• Sap yields were virtually independent of tree age but were directly proportional to tree diameter (Davidov 1979)
• Air temperature and crown diameter were the most important factors affecting yield (Fesyuk 1980)
Sap flow and temperatures
• At the beginning of the sap season, sap flow increases with increasing air temperatures
• At the end of the sap season, sap flow decreaseswith increasing air temperatures
• Sap flow has a closer correlation to soil temperature (15 cm depth) and bole temperature (sapwood portion)
(Ryabchuk 1974)
Site conditions effects• Poorly drained bog sites produce more sap
than dry sites or higher elevation sites
• Sap from drier sites have higher sugar concentrations
(Telisevskij 1970)
Effects of tapping on health of the tree• Tapped trees grow as well as trees that are not
tapped (Lahteenkorva 2005)
• Tapping causes a slight reduction in the current diameter increment compared to untapped trees Exception-- on two plots the diameter increment of the tapped trees were greater than that of the controls (Osipenko and Ryabchuk 1973)
• Tapping for 3 years does not alter the sugar content of the sap (Ryabchuk 1977)
• Tapping for 3-7 years did not have a significant effect in the phenology of the tree (Ryabchuk 1979)
Ukrainian tree tapping guide
(Telisevskij 1970)
tree diameter (cm) # of taps
20-24 1
25-28 2
> 28 3
Affects of multiple taps on sap sugar content
Sugar content tends to decrease with increasing tapping load (Ryabchuk 1977)
Effects of a tap hole on wood discoloration• Wood changes color in the zone above and below the
tapping holes (Ryabchuk 1975)
• 1 meter of longitudinal discoloration (Dujesieken et al. 1989)
• Greatest color change is along the grain; much less in the radial direction, and minimal in the tangential direction holes (Ryabchuk 1975)
• Optical properties (wavelength, purity and brightness) of the discolored wood showed that the brightness of discolored wood was 15.1-20.2% lower than wood from untapped trees (Ryabchuk 1975)
• After the initial discoloration, the color characteristics of the wood did not change significantly (Ryabchuk 1975)
Harvesting sap from stumps• Trees felled with an angle of 160-165 degrees
between the planes of the undercut and the main cut (Gavrilyuk et al. 1980; Osipenko and Ryabchuk 1975)
• Mean sugar content of stump sap and tree sap is almost identical (Ryabchuk 1977)
• Grooves can be cut on the stump surface to guide the sap flow (Gavrilyuk et al. 1980)
• Sap yield was greatest when the felling was done in mid March (Osipenko and Ryabchuk 1975)
Sap research in Alaska• Examined sap harvest at different locales
• Compared sap production temporally
• Identified characteristics that indicate productive stands to tap
Research design
•Three transects•Three sites per transect•Ten trees per site (n=90)•Two full seasons (’02 & ’03)•One preliminary season (one transect ’01)
Sites Transects
Position on slope Ballaine Ester Murphy Dome
top Zachel Calypso Spinach Creek
mid Wood Via Frenchman
Bottom Pearl Creek Garner Moose Mountain
Research designTransects
Position on slope
Ballaine Ester Murphy Dome
top Zachel Calypso Spinach Creek
mid Wood Via Frenchman
bottom Pearl Creek Garner Moose Mountain
Z C SCW V FPC G MM
Results: Vegetation•Closed Paper Birch Forest (AK Vegetation Classification, Viereck 1992)
•Common species include white spruce, apsen, balsam poplar, lingonberry, Labrador tea, prickly rose, twin flower, willow, alder, and lichens
Daily maximum air temperatures for ’01, ’02, & ’03
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
29-Mar 3-Apr 8-Apr 13-Apr 18-Apr 23-Apr 28-Apr 3-May
date
degr
ees
C
2001
2002
2003
95-year meandaily maximumtemperature
April Precipitation
year precip. (cm)2001 0.412002 7.772003 0.13
95 yr average 0.75 (s.d. 1.10)
Results: Sap harvestYear Begin of flow End of sap collection Number of days
2001 April 19th May 8th 19
2002 April 30th May 17th 18
Year Begin of harvest
End of sap harvest
Number of days
2001 April 19th May 8th 19
2002 April 30th May 17th 18
2003 April 19th May 5th 16
Sap harvest per site in ’02 & ’03
0
10
20
30
40
50
60
70
80
90
14-Apr 19-Apr 24-Apr 29-Apr 4-May 9-May 14-May 19-May
L s
ap
Z 2003
W 2003
PC 2003
C 2003
V 2003
G 2003
SC 2003
F 2003
MM 2003
Z 2002
W 2002
PC 2002
C 2002
V 2002
G 2002
SC 2002
2001 Daily maximum air temperatures & sap harvest
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
29-Mar 8-Apr 18-Apr 28-Apr 8-May 18-May 28-May
date
degr
ees
C
-10
0
10
20
30
40
50
60
70
L sa
p
daily max temp
Zachel
Wood
Pearl Creek
Results: Mean sap harvest per tree by site in 2002 & 2003
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
Z W PC C V G SC F MM all
site
L sa
p 02 sap
03 sap
Z C SCW V FPC G MM
Results: Average sugar concentration by site in ’02 & ’03
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Z W PC C V G SC F MM
degr
ees
BR
IX
2002
2003
Z C SCW V FPC G MM
Daily Maximum air temperatures for ’76 & ’77
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
30.0
29-Mar 8-Apr 18-Apr 28-Apr 8-May 18-May 28-May
date
degr
ees
C
1976
1977
95-year meandailytemperature
Distribution of total sap harvest per tree in 2002 & 2003
0
5
10
15
20
25
30
35
40
0-9 10-19 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99
Sap production per tree (L)
per c
ent o
f tre
es
2002
2003
2002 Mean liters of sap harvested per tree from each site
Sites Transects
Position on slope
Ballaine Ester Murphy Dome
top 23.7 (Z)s.d 9.6
30.7 (C)s.d. 11.9
39.3 (SC)s.d. 13.2
mid 32.3 (W)s.d. 11.7
30.0 (V)s.d. 14.1
31.0 (F)s.d. 13.2
bottom 46.9 (PC)s.d. 16.2
42.3 (G)s.d. 20.9
31.3 (MM)s.d. 13.3
Transects
Position on slope
Ballaine Ester Murphy Dome
top23.7 (Z)
s.d 9.630.7 (C)s.d. 11.9
39.3 (SC)s.d. 13.2
mid32.3 (W)
s.d. 11.730.0 (V)s.d. 14.1
31.0 (F)s.d. 13.2
bottom46.9 (PC)
s.d. 16.242.3 (G)s.d. 20.9
31.3 (MM)s.d. 13.3
ANOVA results: 2002• No significant between transects (F= 0.07)• Significance between location on the slope (F= 5.00) • Significant difference considering transect and position on
the slope (F= 3.33) • Bottom significantly different than mid (p= 0.02) and top
sites (p= 0.03)• Mid and top sites not significantly different (p= 1.00)
2003 Mean liters of sap harvested per tree from each site
Sites Transects
Position on slope
Ballaine Ester Murphy Dome
top 11.4 (Z)s.d. 6.5
30.1 (C)s.d. 22.3
23.6 (SC)s.d. 10.9
mid 10.3 (W)s.d. 8.8
21.1 (V)s.d. 13.1
8.4 (F)s.d. 6.0
bottom 51.6 (PC)s.d. 22.6
35.1 (G)s.d. 27.7
8.1 (MM)s.d. 6.9
Transects
Position on slope
Ballaine Ester Murphy Dome
top11.4 (Z)
s.d. 6.530.1 (C)s.d. 22.3
23.6 (SC)s.d. 10.9
mid10.3 (W)
s.d. 8.821.1 (V)s.d. 13.1
8.4 (F)s.d. 6.0
bottom51.6 (PC)
s.d. 22.635.1 (G)s.d. 27.7
8.1 (MM)s.d. 6.9
ANOVA results: 2003
Data violates assumption of normal distribution
VegetationZ W PC C V G SC F MM
Tree species Cover Cover Cover Cover Cover Cover Cover Cover CoverPICGLA 1a 1a 1a 1b 1a 1a 2aPOPTRE 1a 1a p 1aPOPBAL 1a 1aBETNEO 5 5 5 5 5 5 5 5 5
Shrub species Cover Cover Cover Cover Cover Cover Cover Cover CoverVACVIT + r pLEDGRO pROSACI 2a 4 3 1b 1b 2a 1b 4 2aLINBOR + + r r + + 1a 1aSAL spp + 1a 2a 1a 2b 1a +ALN CRI 1a 1a 1a
Forb species Cover Cover Cover Cover Cover Cover Cover Cover CoverPYROLA SP. + r r rVIBEDU 3 2b + 2a 3 1a 1a 2b 2aEPIANG p + 1b 2b 2b 1a 1a 1a +
VegetationMM F W Z SC V G C PC
Tree species Cover Cover Cover Cover Cover Cover Cover Cover CoverPICGLA 2a 1a 1a 1a 1b 1a 1aPOPTRE 1a 1a 1a pPOPBAL 1a 1aBETNEO 5 5 5 5 5 5 5 5 5
Shrub species Cover Cover Cover Cover Cover Cover Cover Cover CoverVACVIT p r +LEDGRO pROSACI 2a 4 4 2a 1b 1b 2a 1b 3LINBOR 1a 1a + + + r + rSAL spp + 1a + 1a 1a 2b 2aALN CRI 1a 1a 1a
Forb species Cover Cover Cover Cover Cover Cover Cover Cover CoverPYROLA SP. r r + rVIBEDU 2a 2b 2b 3 1a 3 1a 2a +EPIANG + 1a + p 1a 2b 1a 2b 1b
Low Performing stands Consistent Performing stands
Sites Moose Mtn, Frenchman, Wood, Zachel Via, Garner, Calypso, Pearl Creek
Criteria <115 L sap per site in ‘03; statistically significant less sap harvested in '03 compared with ‘02
>200 L sap per site in ‘03; not statistically significant less sap harvested in '03 compared with ‘02
Species present only in this group
Populus tremuloides Michx.(TremblingAspen)
Populus balsamifera L. (Balsam Poplar)Pyrola ssp. (Wintergreen) Gallium boreale L. (Northern Bedstraw)
None
Species present in high abundance in this group
Actaea rubra (Ait.) Willd. (Baneberry)Linnaea borealis L. (Twin Flower)Rosa acicularis Lindl. (Prickly Rose)
Salix ssp. (Willow species)Epilobium angustifolium L. (Common Fireweed)Cornus canadensis L. (Dwarf Dogwood)
Species common to both groups
Picea glauca (Moench) Voss (White Spruce)Equisetum pratense L. (Meadow Horsetail)
Hedysarum alpinum L. (Northern Hedysarum)Mertensia paniculata (Ait.) G. Don (Tall Bluebells)
Calamagrostis canadensis (Michx.) Beauv. (Reed Grass)Mosses and Lichens
Ordinal ranking of tree sap production
• Examining for intrinsic factors affecting sap production
• Trees assigned into percentile groups for each year: Top 20%, Top 50%, Bottom 20%, and Bottom 50%
2002 Ranking # of trees that stayed in the same category
# of trees that ranked in Top 20% in 2003
# of trees that ranked in Top 50% in 2003
Top 20% 10/18 10/18 14/18
Top 50% 33/45 14/45 33/45
Bottom 20% 8/18 0/18 1/18
Bottom 50% 33/45 4/45 12/45
Comparison of sap production rank orders between ’02 & ’03
2002 Ranking # of trees that stayed in the same category in 2003
# of trees that ranked in Top 20% in 2003
# of trees that ranked in Top 50% in 2003
Top 20% 10/18 10/18 14/18
Top 50% 33/45 14/45 33/45
Bottom 20% 8/18 0/18 1/18
Bottom 50% 33/45 4/45 12/45
Regression of sap production by tree diameter
0
10
20
30
40
50
60
14 16 18 20 22 24
DBH cm
L sa
p
0
10
20
30
40
50
60
14 16 18 20 22 24
DBH cm
L sa
p
2002R2 = 0.288
slope = 1.79 p = 0.13
2003R2 = .516
slope = 4.61 p = 0.028
Ordinal ranking of tree diameter and sap production
• Examining relationship between tree diameter and sap production
• Trees assigned into percentile groups by dbhand by sap production for each year: Top 20%, Top 50%, Bottom 20%, and Bottom 50%
Comparison of tree diameter rank order and sap production
2002 Ranking # of trees that stayed in the same category
# of trees that ranked in Top 20% in 2003
# of trees that ranked in Top 50% in 2003
Top 20% 10/18 10/18 14/18
Top 50% 33/45 14/45 33/45
Bottom 20% 8/18 0/18 1/18
Bottom 50% 33/45 4/45 12/45
Dbhranking
Sap Production Top 20% in 2002 & 2003
Sap Production Top 20% at least one year
Sap Production Bottom 20% in 2002 & 2003
Sap Production Bottom 20% at least one year
Top 20% 6/18 12/18 0/18 0/18
Top 50% 7/45 19/45 1/45 10/45
Bottom 20% 1/18 2/18 5/18 10/18
Bottom 50% 2/45 8/45 7/45 18/45
Conclusions from field experiments• Trees produced more sap in wet, cool spring of
’02 than dry, warm spring of ’03 • In general, large diameter trees produce more
sap than small diameter tree. This finding is especially true in the dry, warm spring
• Sap production differed in some transects by position on hillside, although other factors can strongly affect amount of sap produced
Recommendations to sap harvesters• Choose stands with willow, firewood, and dwarf
dogwood (especially in dry, warm springs)• Since sap carbohydrate content is fairly
consistent between trees and years, choose trees based on the amount of sap produced
• Choose trees with large diameters or that have produced well in previous years
Future directions for research in Alaska
•Does tapping increase the incidence of pathogens; if so, how can this be minimized
•What is the best way to utilize the sap resource–syrup products, sap beverages
•How can management improve sap yields and/or sugar content
•What does the industry need in order to thrive
ReferencesAlaska Boreal Forest Council. 2005. Review of the 2001 Birch Sap Harvest in Alaska. 4 p.Davidov, G.M. 1979. [Calculating the yield of birch sap by the mensurational characteristics of the stands.]. Lesnoi
Zhurnal. 1 :116-7. Dujesieken, D., S. Ebenritter, and W. Liese. 1989. [Wound reactions in wood tissue in birch, beech, and Tilia
cordata.]. Holzals Roh- und Werkstoff. 47:495-500. Fesyuk, A.V.and V.V. Grimashevich. 1980. [Effects of different factors on the sap yield of Betula pendula.].
Lesovodstvo, Lesnye Kul'tury i Pochvovedenie. 9:89-94. Flora of North America. 1993+. Editorial Committee, editors. Flora of North America North of Mexico. 7+ vols. New
York and Oxford. Available: http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=103887Gavrilyuk, V.M., Yu.O Osipenko, and V.P. Ryabchuk. 1980. [Harvesting sap from stumps.]. Lesnoe Khozyaistvo.
5:62-64. Lahteenkorva, J. 2005. Practical experience of birch sap collection, producing and marketing in Finland. In: Tree Sap
III Proceedings of the 3rd International Symposium on Sap Utilization (ISSU). Bifuka, Hokkaido, Japan, April 15-17 p.7-9.
Osipenko, Yu.F. and V.P. Ryabchuk. 1973. [Effects of tapping [for sap] on the diameter increment of Betulaverrucosa.]. Lesnoe Khozyaistvo. 9:27-9.
Osipenko, Yu.F. and V.P. Ryabchuk. 1975. [Obtaining Birch sap from stumps.]. Lesnoe Khozyaistvo. 4:14-5 .Ryabchuk, V.P. 1974. [Sap exudation of Birch and temperature conditions]. Lesnoe Khyzyaistvo. 5:25-7. Ryabchuk, V.P. 1975. [Effects of tapping Birch on the colour of the wood.]. Lesnoi Zhurnal. 4:146-8. Ryabchuk, V.P. 1977. [The sap of Betula pendula.]. Lesnoe Khozyaistvo. 4:80-2. Ryabchuk, V.P. 1979. [Effects of tapping on the phenological condition of broadleaved species.]. Lesnoi Zhurnal.
1:15-7. Tagiltsev, Y.G., V.A. Tsupko, V.I. Tolstyh, A.G. Izmodenov, E.V. Lysun, R.D. Kolesnikova, and V.S. Ostronkov.
2005. Sap of Far Eastern birch species. In: Tree Sap III Proceedings of the 3rd International Symposium on Sap Utilization (ISSU). Bifuka, Hokkaido, Japan, April 15-17 p.37-42.
Telisevskij, D. 1970. [Collection and use of Birch sap.]. Lesn. Hoz. 80-2. Terazawa, M. 1995. Shirakamba Birch, Splendid Forest Biomass--Potential of Living Tree Tissues. In: Tree Sap
Proceedings of the 1st International Symposium on Sap Utilization (ISSU), Bifuka, Hokkaido, Japan, April 10-12. p. 7-12 .
Tomchuk, R.I. I.S. Korolyak, N.F. Fedchuk, and Ya.G. Kiba. 1973. [Use of Birch sap in the food industry.]. LesnoeKhozyaistvo. 5:16-18.
Viereck L.A. 1992. The Alaska Vegetation Classification. USDA Forest Service General Technical Report. PNW-GTR-286 278 p