MONITORING
THE HEALTH
A CANADIAN
OF A FOREST:
APPROACH
*
P. A. A D D I S O N Canadian Forestry Service, Ottawa, Canada
(Received July 5, 1988) Abstract. In Canada, acid rain is the generic term encompassing all forms of air pollution - wet and dry
deposition, gaseous pollutant concentrations, and airborne particulates. It was because these pollutants, alone or in combination, may directly or indirectly affect the health of Canada's forests, that in 1984, the Canadian Forestry Service initiated a national forest monitoring program (Acid Rain National Early Warning System or ARNEWS). Research studies on pollutant effects of the past 15-20 years have demonstrated that it is not possible to define specific symptoms of acid rain or mixtures of pollutants on native tree species or specific responses of the forest ecosystem. Consequently, ARNEWS monitored incipient acid rain effects by determining the forest's state of health rather than by concentrating on specific pollutant responses. The detection system entails experienced insect and disease survey forest rangers assessing both specific plots and the forest as a whole for extraordinary forest damage. The techniques used include mensurational and symptomatological measurements as well as evaluation of stands for damage from natural and anthropogenic causes. Critical also to the system was the capability of the Canadian Forestry Service to support the detection system with research staff who could carry out studies to explain any abnormalities in forest condition detected during the annual surveys. The ultimate outcome of the monitoring system if unexplained forest damage is detected is a research project on possible causes.
1. Introduction
There is much concern in Canada over the impact of acid rain on our natural resources. Almost half of Canada is forested and although only 64~ is accessible, forest products were the single largest export, contributing $16 billion annually in international trade to the economy (Table I; Economics Branch, 1987). The forests of Canada are also an important part of the heritage of Canadians. This latter aspect is particularly important since Canadians place a very high value on environmental quality. This is demonstrated by the apparent inconsistency of having one of the lowest population densities in the world while having one of the greatest per capita participations in organized environmental advocacy organizations. In dealing with the terrestrial ecosystem in Canada, the term acid rain is used to encompass all forms of air pollution - wet and dry deposition of SO4 and NO3, gaseous pollutant concentrations, and airborne particulates (Addison et al., 1986). We are as concerned about the effects of ozone on the forest as we are about acidic deposition and, in many areas close to the source of pollutants, gas concentrations of SO2 and NOx may be the main pollutant stresses. In addition, volatile organic compounds, other oxidants, and heavy metals may be important components of the * Contribution from 'Fourth World Wilderness Congress - Acid Rain Symposium, Denver (Estes Park), Colorado', September 11-18, 1987.
Environmental Monitoring and Assessment 12: 39-48, 1989. 9 1989 Kluwer Academic Publishers. Printed in the Netherlands
40
P. A. ADDISON
TABLE I The Canadian forest - selected production and problem statistics (adapted from Economics Branch 1987) Area:
Total Area of Canada Inventoried Forested Area Inventoried Productive Forest
917 million ha 342 million ha 220 million ha
Production:
1984 Harvest Species Mix - Softwoods - Hardwoods Total Exports of Wood Products (1985)
168 million m3 92% 8% $16.2 billion
Losses:
Annual Loss to Fire (1973-82) Annual Loss to Insects and Disease (1977-81) Forest Dead and Dying from Spruce Budworm
1.1 million ha 107 million m3 25 million ha
regional pollutant mixture. It was because these pollutants, alone or in combination, have the potential, either directly or indirectly, to affect the health of C a n a d a ' s forests, that in 1984, the Canadian Forestry Service (CFS) initiated a national forest monitoring program (Acid Rain National Early Warning System or ARNEWS). The specific objectives of the A R N E W S program are: ( 1 ) T o detect any forest damage that can not be attributed to natural causes or management practices, and (2) to monitor vegetation and soils on a long-term basis to detect changes attributable to air pollutants and natural stresses in representative forest ecosystems. The situation concerning regional air pollution effects in Canada is substantially different f r o m those in Europe where concerns for the forest are very great. We have few areas where there are declines (Rennie, 1987), and in only a very few stands is there any evidence that pollutants are either present in high concentrations or have an effect. The stands that do show classic pollutant effects are all around strong point sources. C a n a d a has lower pollutant levels than either Europe or the United States both on a regional and national basis (Rennie, 1986). In addition, the forests that are most heavily utilized (softwoods), are those that are most remote from pollution sources (Rennie, in press). Despite the lower pollutant levels and the lack of observed effects, a study that synthesized the opinion of air pollution biologists indicated that they believed that growth losses m a y occur in the future, even at current pollution levels (Fraser et al., 1985). The CFS felt, therefore, that it should be alert for air pollution effects on the forest. 2. Measurement System The Canadian Forestry Service has had about 50 years of experience in detecting and monitoring air pollution effects on the forests around point sources such as Trail,
M O N I T O R I N G T H E H E A L T H OF A FOREST: A C A N A D I A N A P P R O A C H
41
British Columbia (Katz, 1929), Sudbury, Ontario (Linzon, 1958), Fort McMurray, Alberta (Addison, 1980), and Long Harbour, Newfoundland (Sidhu, 1979). Initially, therefore, it was thought that specific measurable effects of air pollution impact could be selected and incorporated into the national network. A monitoring network must demonstrate that the pollutants of interest are both present and affecting the forest ecosystem (Addison, 1982). The measurement of pollutant presence was the first step, but it rapidly became apparent that the expense of operating a network of atmospheric monitoring stations for all possible phytotoxic pollutants was impracticable. As a result, attempts were made to use biological measures of pollutant deposition such as pollutant content of plant and soil material. The potential for the pollutant content of lichen and vascular plant and oil material to provide an estimate of the deposition of air pollutants was examined quantitatively. There was tremendous variability in chemical composition of plant and soil material within the forest ecosystem (Maynard and Addison, 1986). In addition, it was not possible to measure pollutants such as ozone or hydrogen peroxide in soil and plant material. Deposition rates were low both in absolute terms (heavy metals) and relative to the natural occurrence of these compounds (SO4, NOa). Therefore, it would not be possible to monitor the deposition rates expected in Canada precisely and only large changes could be detected. The network had to rely on the general pattern of air pollution deposition determined by the national atmospheric monitoring program to compare with forest responses. The problems with precise monitoring of biological responses to pollutant deposition were even greater. Many biological processes have been demonstrated to respond to air pollutants in the laboratory and around strong point sources. In regional air pollution, however, specific responses of forest ecosystems to air pollution have not been found. Variability in biological measurements is even greater than that of soil and vegetation chemical composition (Maynard and Addison, 1986). In addition, biological systems tend to respond to the environmental complex rather than to any specific factor in that complex such as air pollution. Many other components of the environmental complex such as insect damage, diseases, climate, fire, and soils affect the 342 million hectares of the Canadian forest (Table I). These natural factors have such a tremendous impact on the forest that any subtle response caused by air pollution is exceptionally difficult to quantify or even detect. The CFS approach, therefore, was to assess the forest's state of health rather than to try to use specific quantitative measures of air pollution deposition or response. This approach entailed the use of a common set of measurements taken at specific plots established for ARNEWS by the Forest Insect and Disease Survey (FIDS). Also, air pollution was added as a factor in all assessments of forest condition carried out as part of the regular survey of the 220 million hectares of productive forest by FIDS. The role of FIDS in ARNEWS was to identify areas where forest damage could not be explained by natural factors. Critical also to the system was the capability of the CFS to support the survey with research staff who could carry out studies to explain any abnormalities in forest condition detected during the annual surveys. The
42
P . A. ADDISON
TABLE II Monitoring parameters for ARNEWS plots (adapted from Magasi 1988) Base year plus every-5-year assessment:
Radial growth Vertical growth Crown structure and density Foliage sampling for analysis Soil sampling for analysis Base year plus annual assessment:
Tree mortality Tree condition Visible foliar symptoms (pollution and natural stresses) Base year plus two assessments per growing season:
Insect and disease conditions Visible foliar symptoms (pollution and natural stresses) Seed production
ultimate outcome of the monitoring system if unexplained forest damage is detected is the development of a research project on possible causes. Various quantitative methods are used to provide a measure of forest condition that can be monitored over time (Table II; Magasi, 1988). Specific plots were used so that the variation f r o m location to location could be eliminated through the repetitive examination of permanently marked sites. Tree growth measurements are used extensively because of the potential for economic losses to C a n a d a ' s major industry. Records of leaf chlorosis and defoliation are similar to those of the European monitoring system except that no attempt is made to relate either measurement to a theoretically 'healthy' tree (P.C.C., 1986). Measurements of foliage and soil chemical composition are collected to provide information on site fertility and a baseline with which to compare future measurements. The parameters measured are divided into three classes based upon both the frequency and purpose of the measurements (Magasi, 1988). Five year intervals are used between measurements of growth, crown structure and density, and foliar and soil elemental contents. These measures together with the standard measurements taken to characterize site and stand (for example, slope, aspect, dominants etc.) provided the initial description of the plots. Tree condition and foliar symptom assessment as well as insect and disease conditions are evaluated on an annual or twice annual basis. In most cases, surveys for insects and diseases must be carried out at various times of the year to quantify the impact of all m a j o r forest pests. 3. Results Owing to the nature of pollution distribution (Figure 1), a total of 106 plots were established across C a n a d a (Figure 2), with most sites located in Eastern Canada. Attempts were made to monitor and assess commercially important forest types in
SPECIES
~
'
~
fir,
hemlock,
Sitka
spruce .............................
IHI:HI[I
Fig. 1.
~
I
-~
~
~
~_J ~ _ _ ~ o
0o
~" ~ -~ ~/~._. ~'\\
\
~
~ .
1957
kg ha- 1 yr- 1
Acid Sulphate Deposition i
CANSAP DATA, 1981
S C A L E IN M I L E S
FOREST CLASSIoFIFCATION
Forest Regions of Canada (Rowe 1972) with isopleths of 1981 levels of SO4 deposition (Rennie 1987a),
~3ra~sland ................................................................................................................. Tundra .....................................................................................................................
C o ~ u m b , ~ .................................. White pine, lerch, Dougt~ fir, s p r u c e . . . . . . . . . . . . . . . . . . . . . . . . ~ 1 Dec,duous ................................. Maple beech, lulip - tree, walnut ere .......................... I ~teat Lakes - St L~w~ence ....... M~ple, beech wh~te pine, yellow birch, hemlock .......... Acad,an ................................... ~pcuce, b a l s a m fir, b i r c h , m a p l e , b e e c h , p i n e . . . . . . . . . . . . i::: : : : : t
......................................
Douglas
TREE
Coast
PRINCIPAL
LEOEND
~spe~ ..................................................................... r~zx~ Spruce .................................................................... It/////) Engelmann S p r u c e . I o d ~ l e p o l e p i n e , a l p i n e fir . . . . . . . . . . . . . . I : Lodgepole p i n e , a s p e n , s p r u c e , D o u g l a s fir . . . . . . . . . . . . . . . . . ~ l
REGIONS
i
Forest &~d ~rassla~d ............... Fores1 and Barren .................... S u b a l p l n e ................................. M o n t a n e ...................................
FOREST Eloreal
P
/
/
,.e
0
>
0
0
-t
m ,.e
0
0
z
o
44
P . A . ADDISON
s .~
"~.
~
)
/ 9 9
i
/.
/
I'
,
ol
"~\ -.
--~.....
~
~
i
9
, i
Fig. 2.
9
o_ 9
C a n a d a showing site locations for the Canadian Acid Rain National Early Warning System.
each province (Table III) concentrating on white spruce; the only commercial tree species common across Canada. The ARNEWS system has proven its capability to detect damage to forests, and both maple decline and birch deterioration were identified by the monitoring system. 3.1. MAPLE DECLINE Initial surveys of declining maple stands in cooperation with the Province of Quebec indicated that no one factor such as elevation, management practices, tapping, or insects could account for the observed damage. Since the immediate cause or causes of the current maple decline could not be identified, a research project was initiated in 1986. This project started a process by which research into the maple decline phenomenon has been coordinated at several levels. The CFS, which has traditionally studied maple silviculture and management, expanded its program to include work on nutrient cycling, symptomology of air pollution injury, and the influence of ozone on maple. The Government of Quebec also increased its efforts through both the Ministry of Energy and Resources and the Ministry of Agriculture, Fisheries and
MONITORING THE HEALTH OF A FOREST: A CANADIAN APPROACH
45
T A B L E III Distribution of A R N E W S plots by province
Province Newfoundland Prince Edward Island Nova Scotia New Brunswick Quebec Ontario Manitoba Saskatchewan Alberta British Columbia Total
Number of Sites 10 1 6 10 25 27 4 3 5 15 106
Food. These two ministries, respectively, deal with the mechanisms of air pollution impact and the survey and monitoring of the health of maple stands. A joint project has also been developed with the United States Forest Service and several northeastern states. This project will act as a unifying structure for the numerous studies into the maple decline problem in both Canada and the United States. Its objectives are to: (1) Determine the rate of change in the condition of sugar maple trees during the 1988-90 period. (2) Determine whether the rate of change in sugar maple condition is affected by: (a) SO4 deposition level, (b) forest management (sugar bush versus unmanaged forest), (c) initial level of forest decline. (3) Determine the possible causes of sugar maple decline and the geographic relationship between cause and extent of decline. In 1987, a methods manual was developed through an iterative process among the scientists on both sides of the border. The manual was tested in the field during the summer of 1987 by a joint US/Canadian team of scientists. This manual with its quality assurance plan (Millers and Lachance, 1988) is available through either the Hardwood Cooperative of the United States NAPAP Forest Response Program or the Canadian Forestry Service Long-Range Transport of Air Pollution Program. 3.2. BIRCH DETERIORATION Early leaf browing and premature leaf drop of birch was detected in southern New Brunswick along the Bay of Fundy (Magasi, 1985). The intensity of effect has varied greatly among years and extended to alder, largetooth and trembling aspen, mountain ash, and mountain maple in some locations. Many natural factors were considered as possible causes (Table IV) but after a detailed analysis, none either
46
P. A. ADDISON TABLE IV Possible factors causing birch deterioration in the Bay of Fundy area (personal communication, L.P. Magasi 1986).
Biological Factors: Septoria betulina Agrilus anxius Trypodendron betulae Xylococculus betulae Acaphylla distata
(Leaf spot fungus) (Bronze birch borer) (Birch ambrosia beetle) (Birch scale) (Eriophyid mite)
Physical Factors: Drought Logging practices Road salting Ocean salt spray Storm events Global climate change Local air pollution Long-range air pollution
individually or in combination could account for the overall pattern (personal communication, L.P. Magasi, 1986). Since the symptoms could not be attributed to any known vector, a project was initiated to determine the cause. This study is being carried out in cooperation with the Province of New Brunswick and Environment Canada. Measurements include continued monitoring of visible symptoms at 11 locations supported by studies into the effects of rain chemistry, fog chemistry, and ozone concentrations on the birch forest. Initial observations indicate that a pollution response is the most likely hypothesis. The pH of fog and precipitation can be very low and the ozone levels are relatively high. Since there are local sources of both SO2 and the precursors of ozone, the contribution from long-range versus short-range transport of air pollutants is a critical component that has yet to be determined. 4. Conclusions
Generally, the Canadian Acid Rain National Early Warning System deals with extraordinary forest damage. The term 'Early Warning' does not refer to detecting previsible injury which has never been possible in any rigorous and reproducible manner under field conditions (Addison et al., 1986). The system does, however, provide an early warning of large-scale forest injury such as that reported in Europe. It accomplishes this by detecting relatively small areas where the causes of forest injury are not obvious. This detection mechanism, when combined with the potential to determine those causes through research, provides a system that identifies the natural and anthropogenic factors that can effect the productivity and survival of Canada's forests.
MONITORING THE HEALTH OF A FOREST: A CANADIAN APPROACH
47
Acknowledgements The ARNEWS system is the result of a great deal of discussion among scientists from both the Forest Insect and Disease Survey and the Long-Range Transport of Air Pollution Program of the Canadian Forestry Service. The system could not have been developed or implemented without the tremendous amount of cooperation and good will between these two programs.
References Addison, P. A.: 1980, 'Baseline Condition of Jack Pine Biomonitoring Plots in the Athabasca Oil Sands Area, 1976 and 1977', Alberta Oil Sands Environmental Research Program Report No. 98, Alberta Environment, 38 pp. Addison, P. A.: 1982, 'Biomonitoring in the Athabasca Oil Sands Area: Progress and Pitfalls', p. 331-367, in Symposium/Workshop Proceedings: Acid Forming Emissions in Alberta and their Ecological Effects, Alberta Department of Environment, Canadian Petroleum Association, Oil Sands Environmental Study Group, Edmonton, Alberta. 648 pp. Addison, P. A., L'Hirondelle, S. J., Maynard, D. G., Malhotra, S. S., and Khan, A. A.: 1987, 'Effect of Oil Sands Processing Emissions on the Boreal Forest', Canadian Forestry Service Information Report NOR-X-284, Edmonton, Alberta. Addison, P. A., Linzon, S. N., and Hogan, G. D. (eds.): 1986, 'Assessment of the State of Knowledge on the Long-Range Transport of Air Pollutants and Acid Deposition: Part 4, Terrestrial Effects', Research Monitoring and Coordinating Committee, Downsview, Ontario. Economics Branch: 1987, 'Selected Forestry Statistics Canada 1986', Canadian Forestry Service Information Report E-X-38, Ottawa, Canada, 180 pp. Fraser, G. A., Phillips, W. E., Lamble, G. W., Hogan, G. D., and Teskey, A. G.: 1985, 'The Potential Impact of the Long-Range Transport of Air Pollutants on Canadian Forests', Canadian Forestry Service Information Report E-X-36. Katz, M.: 1929, 'Suphur Dioxide in the Atmosphere and its Relation to Plant Life', Ind. Eng. Chem. 41, 2450. Linzon, S. N.: 1958, 'The Influence of Smelter Fumes on the Growth of White Pine in the Sudbury Region', Joint Publ. Ontario Dept. Lands and Forests, Ontario Dept. Mines. Toronto. Magasi, L. P.: 1985, 'Forest Pest Condition in the Maritimes', Canadian Forestry Service Information Report M-X-159, Fredericton, New Brunswick. Magasi, L. P.: 1988, 'Acid Rain National Early Warning System Manual on Plot Establishment and Monitoring', Canadian Forestry Service Information Report, DPC-X-25, Ottawa, Canada. Maynard, D. G. and Addison, P. A.: 1986, 'Variability in Forest Systems as it Relates to Elemental Sulphur Effects', p. 255-285, in Proc. Second Symposium/Workshop on Acid Forming Emissions in Alberta and their Ecological Effects, Research Management Division, Alberta Environment, Edmonton. 354 pp. Millers, I. and Lachance, D.: 1988, 'Quality Assurance and Quality Control Plan', North American Sugar Maple Decline Project, Joint Report of the U.S. Forest Service, Durham, NH, and the Canadian Forestry Service, Sainte-Foy, Quebec. Program Co-ordinating Centres: 1986, 'International Co-Operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests Manual on Methodologies and Criteria for Harmonized Sampling, Assessment, Monitoring and Analysis of the Effects of Air Pollution on Forests', Prep. by the Programme Co-ordinating Centres with the Assistance of the United Nations Environment Programme and the Secretariat of the United Nations Economic Commission for Europe, Hamburg, West Germany. Rennie, P. J.: 1986, 'A Review of Canadian Investigation', in Proc. of the 67th Annual Meeting, Canadian Pulp and Paper Association, Session 9 on Acid Deposition and Forest Health, Montreal, Quebec. Rennie, P. J.: 1987, 'The Significance of Air Pollution to Forest Decline in Canada', in Proc. Workshop
48
P . A . ADDISON
on Forest Decline and Reproduction: Regional and Global Consequences, International Institute for Applied Systems Analysis and Polish Academy of Sciences, Krakow, Poland. Rennie, P. J.: 1987, 'Air Pollution and the Forestry Sector: Challenges and Requirements', in Lavender, D. P. (ed.), Proc. of the IUFRO Workshop on Woody Plant Growth in a Changing Physical and Chemical Environment. 27-31 July, 1987. Vancouver, British Columbia (in press). Rowe, J. S.: 1972, 'Forest Regions of Canada', Canadian Forestry Service Publication No. 1300, Ottawa, Canada, 172 pp. Sidhu, S. S.: 1979, 'Fluoride Levels in Air, Vegetation and Soil in the Vicinity of a Phosphorus Plant', J. Air Pollut. Control Assoc. 29, 1069.
THE HEALTH
A CANADIAN
OF A FOREST:
APPROACH
*
P. A. A D D I S O N Canadian Forestry Service, Ottawa, Canada
(Received July 5, 1988) Abstract. In Canada, acid rain is the generic term encompassing all forms of air pollution - wet and dry
deposition, gaseous pollutant concentrations, and airborne particulates. It was because these pollutants, alone or in combination, may directly or indirectly affect the health of Canada's forests, that in 1984, the Canadian Forestry Service initiated a national forest monitoring program (Acid Rain National Early Warning System or ARNEWS). Research studies on pollutant effects of the past 15-20 years have demonstrated that it is not possible to define specific symptoms of acid rain or mixtures of pollutants on native tree species or specific responses of the forest ecosystem. Consequently, ARNEWS monitored incipient acid rain effects by determining the forest's state of health rather than by concentrating on specific pollutant responses. The detection system entails experienced insect and disease survey forest rangers assessing both specific plots and the forest as a whole for extraordinary forest damage. The techniques used include mensurational and symptomatological measurements as well as evaluation of stands for damage from natural and anthropogenic causes. Critical also to the system was the capability of the Canadian Forestry Service to support the detection system with research staff who could carry out studies to explain any abnormalities in forest condition detected during the annual surveys. The ultimate outcome of the monitoring system if unexplained forest damage is detected is a research project on possible causes.
1. Introduction
There is much concern in Canada over the impact of acid rain on our natural resources. Almost half of Canada is forested and although only 64~ is accessible, forest products were the single largest export, contributing $16 billion annually in international trade to the economy (Table I; Economics Branch, 1987). The forests of Canada are also an important part of the heritage of Canadians. This latter aspect is particularly important since Canadians place a very high value on environmental quality. This is demonstrated by the apparent inconsistency of having one of the lowest population densities in the world while having one of the greatest per capita participations in organized environmental advocacy organizations. In dealing with the terrestrial ecosystem in Canada, the term acid rain is used to encompass all forms of air pollution - wet and dry deposition of SO4 and NO3, gaseous pollutant concentrations, and airborne particulates (Addison et al., 1986). We are as concerned about the effects of ozone on the forest as we are about acidic deposition and, in many areas close to the source of pollutants, gas concentrations of SO2 and NOx may be the main pollutant stresses. In addition, volatile organic compounds, other oxidants, and heavy metals may be important components of the * Contribution from 'Fourth World Wilderness Congress - Acid Rain Symposium, Denver (Estes Park), Colorado', September 11-18, 1987.
Environmental Monitoring and Assessment 12: 39-48, 1989. 9 1989 Kluwer Academic Publishers. Printed in the Netherlands
40
P. A. ADDISON
TABLE I The Canadian forest - selected production and problem statistics (adapted from Economics Branch 1987) Area:
Total Area of Canada Inventoried Forested Area Inventoried Productive Forest
917 million ha 342 million ha 220 million ha
Production:
1984 Harvest Species Mix - Softwoods - Hardwoods Total Exports of Wood Products (1985)
168 million m3 92% 8% $16.2 billion
Losses:
Annual Loss to Fire (1973-82) Annual Loss to Insects and Disease (1977-81) Forest Dead and Dying from Spruce Budworm
1.1 million ha 107 million m3 25 million ha
regional pollutant mixture. It was because these pollutants, alone or in combination, have the potential, either directly or indirectly, to affect the health of C a n a d a ' s forests, that in 1984, the Canadian Forestry Service (CFS) initiated a national forest monitoring program (Acid Rain National Early Warning System or ARNEWS). The specific objectives of the A R N E W S program are: ( 1 ) T o detect any forest damage that can not be attributed to natural causes or management practices, and (2) to monitor vegetation and soils on a long-term basis to detect changes attributable to air pollutants and natural stresses in representative forest ecosystems. The situation concerning regional air pollution effects in Canada is substantially different f r o m those in Europe where concerns for the forest are very great. We have few areas where there are declines (Rennie, 1987), and in only a very few stands is there any evidence that pollutants are either present in high concentrations or have an effect. The stands that do show classic pollutant effects are all around strong point sources. C a n a d a has lower pollutant levels than either Europe or the United States both on a regional and national basis (Rennie, 1986). In addition, the forests that are most heavily utilized (softwoods), are those that are most remote from pollution sources (Rennie, in press). Despite the lower pollutant levels and the lack of observed effects, a study that synthesized the opinion of air pollution biologists indicated that they believed that growth losses m a y occur in the future, even at current pollution levels (Fraser et al., 1985). The CFS felt, therefore, that it should be alert for air pollution effects on the forest. 2. Measurement System The Canadian Forestry Service has had about 50 years of experience in detecting and monitoring air pollution effects on the forests around point sources such as Trail,
M O N I T O R I N G T H E H E A L T H OF A FOREST: A C A N A D I A N A P P R O A C H
41
British Columbia (Katz, 1929), Sudbury, Ontario (Linzon, 1958), Fort McMurray, Alberta (Addison, 1980), and Long Harbour, Newfoundland (Sidhu, 1979). Initially, therefore, it was thought that specific measurable effects of air pollution impact could be selected and incorporated into the national network. A monitoring network must demonstrate that the pollutants of interest are both present and affecting the forest ecosystem (Addison, 1982). The measurement of pollutant presence was the first step, but it rapidly became apparent that the expense of operating a network of atmospheric monitoring stations for all possible phytotoxic pollutants was impracticable. As a result, attempts were made to use biological measures of pollutant deposition such as pollutant content of plant and soil material. The potential for the pollutant content of lichen and vascular plant and oil material to provide an estimate of the deposition of air pollutants was examined quantitatively. There was tremendous variability in chemical composition of plant and soil material within the forest ecosystem (Maynard and Addison, 1986). In addition, it was not possible to measure pollutants such as ozone or hydrogen peroxide in soil and plant material. Deposition rates were low both in absolute terms (heavy metals) and relative to the natural occurrence of these compounds (SO4, NOa). Therefore, it would not be possible to monitor the deposition rates expected in Canada precisely and only large changes could be detected. The network had to rely on the general pattern of air pollution deposition determined by the national atmospheric monitoring program to compare with forest responses. The problems with precise monitoring of biological responses to pollutant deposition were even greater. Many biological processes have been demonstrated to respond to air pollutants in the laboratory and around strong point sources. In regional air pollution, however, specific responses of forest ecosystems to air pollution have not been found. Variability in biological measurements is even greater than that of soil and vegetation chemical composition (Maynard and Addison, 1986). In addition, biological systems tend to respond to the environmental complex rather than to any specific factor in that complex such as air pollution. Many other components of the environmental complex such as insect damage, diseases, climate, fire, and soils affect the 342 million hectares of the Canadian forest (Table I). These natural factors have such a tremendous impact on the forest that any subtle response caused by air pollution is exceptionally difficult to quantify or even detect. The CFS approach, therefore, was to assess the forest's state of health rather than to try to use specific quantitative measures of air pollution deposition or response. This approach entailed the use of a common set of measurements taken at specific plots established for ARNEWS by the Forest Insect and Disease Survey (FIDS). Also, air pollution was added as a factor in all assessments of forest condition carried out as part of the regular survey of the 220 million hectares of productive forest by FIDS. The role of FIDS in ARNEWS was to identify areas where forest damage could not be explained by natural factors. Critical also to the system was the capability of the CFS to support the survey with research staff who could carry out studies to explain any abnormalities in forest condition detected during the annual surveys. The
42
P . A. ADDISON
TABLE II Monitoring parameters for ARNEWS plots (adapted from Magasi 1988) Base year plus every-5-year assessment:
Radial growth Vertical growth Crown structure and density Foliage sampling for analysis Soil sampling for analysis Base year plus annual assessment:
Tree mortality Tree condition Visible foliar symptoms (pollution and natural stresses) Base year plus two assessments per growing season:
Insect and disease conditions Visible foliar symptoms (pollution and natural stresses) Seed production
ultimate outcome of the monitoring system if unexplained forest damage is detected is the development of a research project on possible causes. Various quantitative methods are used to provide a measure of forest condition that can be monitored over time (Table II; Magasi, 1988). Specific plots were used so that the variation f r o m location to location could be eliminated through the repetitive examination of permanently marked sites. Tree growth measurements are used extensively because of the potential for economic losses to C a n a d a ' s major industry. Records of leaf chlorosis and defoliation are similar to those of the European monitoring system except that no attempt is made to relate either measurement to a theoretically 'healthy' tree (P.C.C., 1986). Measurements of foliage and soil chemical composition are collected to provide information on site fertility and a baseline with which to compare future measurements. The parameters measured are divided into three classes based upon both the frequency and purpose of the measurements (Magasi, 1988). Five year intervals are used between measurements of growth, crown structure and density, and foliar and soil elemental contents. These measures together with the standard measurements taken to characterize site and stand (for example, slope, aspect, dominants etc.) provided the initial description of the plots. Tree condition and foliar symptom assessment as well as insect and disease conditions are evaluated on an annual or twice annual basis. In most cases, surveys for insects and diseases must be carried out at various times of the year to quantify the impact of all m a j o r forest pests. 3. Results Owing to the nature of pollution distribution (Figure 1), a total of 106 plots were established across C a n a d a (Figure 2), with most sites located in Eastern Canada. Attempts were made to monitor and assess commercially important forest types in
SPECIES
~
'
~
fir,
hemlock,
Sitka
spruce .............................
IHI:HI[I
Fig. 1.
~
I
-~
~
~
~_J ~ _ _ ~ o
0o
~" ~ -~ ~/~._. ~'\\
\
~
~ .
1957
kg ha- 1 yr- 1
Acid Sulphate Deposition i
CANSAP DATA, 1981
S C A L E IN M I L E S
FOREST CLASSIoFIFCATION
Forest Regions of Canada (Rowe 1972) with isopleths of 1981 levels of SO4 deposition (Rennie 1987a),
~3ra~sland ................................................................................................................. Tundra .....................................................................................................................
C o ~ u m b , ~ .................................. White pine, lerch, Dougt~ fir, s p r u c e . . . . . . . . . . . . . . . . . . . . . . . . ~ 1 Dec,duous ................................. Maple beech, lulip - tree, walnut ere .......................... I ~teat Lakes - St L~w~ence ....... M~ple, beech wh~te pine, yellow birch, hemlock .......... Acad,an ................................... ~pcuce, b a l s a m fir, b i r c h , m a p l e , b e e c h , p i n e . . . . . . . . . . . . i::: : : : : t
......................................
Douglas
TREE
Coast
PRINCIPAL
LEOEND
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REGIONS
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44
P . A . ADDISON
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C a n a d a showing site locations for the Canadian Acid Rain National Early Warning System.
each province (Table III) concentrating on white spruce; the only commercial tree species common across Canada. The ARNEWS system has proven its capability to detect damage to forests, and both maple decline and birch deterioration were identified by the monitoring system. 3.1. MAPLE DECLINE Initial surveys of declining maple stands in cooperation with the Province of Quebec indicated that no one factor such as elevation, management practices, tapping, or insects could account for the observed damage. Since the immediate cause or causes of the current maple decline could not be identified, a research project was initiated in 1986. This project started a process by which research into the maple decline phenomenon has been coordinated at several levels. The CFS, which has traditionally studied maple silviculture and management, expanded its program to include work on nutrient cycling, symptomology of air pollution injury, and the influence of ozone on maple. The Government of Quebec also increased its efforts through both the Ministry of Energy and Resources and the Ministry of Agriculture, Fisheries and
MONITORING THE HEALTH OF A FOREST: A CANADIAN APPROACH
45
T A B L E III Distribution of A R N E W S plots by province
Province Newfoundland Prince Edward Island Nova Scotia New Brunswick Quebec Ontario Manitoba Saskatchewan Alberta British Columbia Total
Number of Sites 10 1 6 10 25 27 4 3 5 15 106
Food. These two ministries, respectively, deal with the mechanisms of air pollution impact and the survey and monitoring of the health of maple stands. A joint project has also been developed with the United States Forest Service and several northeastern states. This project will act as a unifying structure for the numerous studies into the maple decline problem in both Canada and the United States. Its objectives are to: (1) Determine the rate of change in the condition of sugar maple trees during the 1988-90 period. (2) Determine whether the rate of change in sugar maple condition is affected by: (a) SO4 deposition level, (b) forest management (sugar bush versus unmanaged forest), (c) initial level of forest decline. (3) Determine the possible causes of sugar maple decline and the geographic relationship between cause and extent of decline. In 1987, a methods manual was developed through an iterative process among the scientists on both sides of the border. The manual was tested in the field during the summer of 1987 by a joint US/Canadian team of scientists. This manual with its quality assurance plan (Millers and Lachance, 1988) is available through either the Hardwood Cooperative of the United States NAPAP Forest Response Program or the Canadian Forestry Service Long-Range Transport of Air Pollution Program. 3.2. BIRCH DETERIORATION Early leaf browing and premature leaf drop of birch was detected in southern New Brunswick along the Bay of Fundy (Magasi, 1985). The intensity of effect has varied greatly among years and extended to alder, largetooth and trembling aspen, mountain ash, and mountain maple in some locations. Many natural factors were considered as possible causes (Table IV) but after a detailed analysis, none either
46
P. A. ADDISON TABLE IV Possible factors causing birch deterioration in the Bay of Fundy area (personal communication, L.P. Magasi 1986).
Biological Factors: Septoria betulina Agrilus anxius Trypodendron betulae Xylococculus betulae Acaphylla distata
(Leaf spot fungus) (Bronze birch borer) (Birch ambrosia beetle) (Birch scale) (Eriophyid mite)
Physical Factors: Drought Logging practices Road salting Ocean salt spray Storm events Global climate change Local air pollution Long-range air pollution
individually or in combination could account for the overall pattern (personal communication, L.P. Magasi, 1986). Since the symptoms could not be attributed to any known vector, a project was initiated to determine the cause. This study is being carried out in cooperation with the Province of New Brunswick and Environment Canada. Measurements include continued monitoring of visible symptoms at 11 locations supported by studies into the effects of rain chemistry, fog chemistry, and ozone concentrations on the birch forest. Initial observations indicate that a pollution response is the most likely hypothesis. The pH of fog and precipitation can be very low and the ozone levels are relatively high. Since there are local sources of both SO2 and the precursors of ozone, the contribution from long-range versus short-range transport of air pollutants is a critical component that has yet to be determined. 4. Conclusions
Generally, the Canadian Acid Rain National Early Warning System deals with extraordinary forest damage. The term 'Early Warning' does not refer to detecting previsible injury which has never been possible in any rigorous and reproducible manner under field conditions (Addison et al., 1986). The system does, however, provide an early warning of large-scale forest injury such as that reported in Europe. It accomplishes this by detecting relatively small areas where the causes of forest injury are not obvious. This detection mechanism, when combined with the potential to determine those causes through research, provides a system that identifies the natural and anthropogenic factors that can effect the productivity and survival of Canada's forests.
MONITORING THE HEALTH OF A FOREST: A CANADIAN APPROACH
47
Acknowledgements The ARNEWS system is the result of a great deal of discussion among scientists from both the Forest Insect and Disease Survey and the Long-Range Transport of Air Pollution Program of the Canadian Forestry Service. The system could not have been developed or implemented without the tremendous amount of cooperation and good will between these two programs.
References Addison, P. A.: 1980, 'Baseline Condition of Jack Pine Biomonitoring Plots in the Athabasca Oil Sands Area, 1976 and 1977', Alberta Oil Sands Environmental Research Program Report No. 98, Alberta Environment, 38 pp. Addison, P. A.: 1982, 'Biomonitoring in the Athabasca Oil Sands Area: Progress and Pitfalls', p. 331-367, in Symposium/Workshop Proceedings: Acid Forming Emissions in Alberta and their Ecological Effects, Alberta Department of Environment, Canadian Petroleum Association, Oil Sands Environmental Study Group, Edmonton, Alberta. 648 pp. Addison, P. A., L'Hirondelle, S. J., Maynard, D. G., Malhotra, S. S., and Khan, A. A.: 1987, 'Effect of Oil Sands Processing Emissions on the Boreal Forest', Canadian Forestry Service Information Report NOR-X-284, Edmonton, Alberta. Addison, P. A., Linzon, S. N., and Hogan, G. D. (eds.): 1986, 'Assessment of the State of Knowledge on the Long-Range Transport of Air Pollutants and Acid Deposition: Part 4, Terrestrial Effects', Research Monitoring and Coordinating Committee, Downsview, Ontario. Economics Branch: 1987, 'Selected Forestry Statistics Canada 1986', Canadian Forestry Service Information Report E-X-38, Ottawa, Canada, 180 pp. Fraser, G. A., Phillips, W. E., Lamble, G. W., Hogan, G. D., and Teskey, A. G.: 1985, 'The Potential Impact of the Long-Range Transport of Air Pollutants on Canadian Forests', Canadian Forestry Service Information Report E-X-36. Katz, M.: 1929, 'Suphur Dioxide in the Atmosphere and its Relation to Plant Life', Ind. Eng. Chem. 41, 2450. Linzon, S. N.: 1958, 'The Influence of Smelter Fumes on the Growth of White Pine in the Sudbury Region', Joint Publ. Ontario Dept. Lands and Forests, Ontario Dept. Mines. Toronto. Magasi, L. P.: 1985, 'Forest Pest Condition in the Maritimes', Canadian Forestry Service Information Report M-X-159, Fredericton, New Brunswick. Magasi, L. P.: 1988, 'Acid Rain National Early Warning System Manual on Plot Establishment and Monitoring', Canadian Forestry Service Information Report, DPC-X-25, Ottawa, Canada. Maynard, D. G. and Addison, P. A.: 1986, 'Variability in Forest Systems as it Relates to Elemental Sulphur Effects', p. 255-285, in Proc. Second Symposium/Workshop on Acid Forming Emissions in Alberta and their Ecological Effects, Research Management Division, Alberta Environment, Edmonton. 354 pp. Millers, I. and Lachance, D.: 1988, 'Quality Assurance and Quality Control Plan', North American Sugar Maple Decline Project, Joint Report of the U.S. Forest Service, Durham, NH, and the Canadian Forestry Service, Sainte-Foy, Quebec. Program Co-ordinating Centres: 1986, 'International Co-Operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests Manual on Methodologies and Criteria for Harmonized Sampling, Assessment, Monitoring and Analysis of the Effects of Air Pollution on Forests', Prep. by the Programme Co-ordinating Centres with the Assistance of the United Nations Environment Programme and the Secretariat of the United Nations Economic Commission for Europe, Hamburg, West Germany. Rennie, P. J.: 1986, 'A Review of Canadian Investigation', in Proc. of the 67th Annual Meeting, Canadian Pulp and Paper Association, Session 9 on Acid Deposition and Forest Health, Montreal, Quebec. Rennie, P. J.: 1987, 'The Significance of Air Pollution to Forest Decline in Canada', in Proc. Workshop
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P . A . ADDISON
on Forest Decline and Reproduction: Regional and Global Consequences, International Institute for Applied Systems Analysis and Polish Academy of Sciences, Krakow, Poland. Rennie, P. J.: 1987, 'Air Pollution and the Forestry Sector: Challenges and Requirements', in Lavender, D. P. (ed.), Proc. of the IUFRO Workshop on Woody Plant Growth in a Changing Physical and Chemical Environment. 27-31 July, 1987. Vancouver, British Columbia (in press). Rowe, J. S.: 1972, 'Forest Regions of Canada', Canadian Forestry Service Publication No. 1300, Ottawa, Canada, 172 pp. Sidhu, S. S.: 1979, 'Fluoride Levels in Air, Vegetation and Soil in the Vicinity of a Phosphorus Plant', J. Air Pollut. Control Assoc. 29, 1069.
