Motorists fortunate enough to be able to cruise Highway # 16 between Wynyard and Kandahar can't help but notice the miles of field shelterbelts that have been planted. Some of the trees were planted in the late 40's so have been a regular feature of the landscape for a long time. One of the tree rows of caragana on the north side of the road is especially interesting because every so often, 10 m of the row has been cut back to ground level. Those trees were part of a study conducted by the PFRA Shelterbelt Centre to determine the biomass production and carbon fixation of prairie field shelterbelts.
Using funds from the Green Plan, John Kort and Bob Turnock conducted the study from 1994 to 1996. The objective of the project was to determine the amount of biomass and carbon in prairie shelterbelts and to explore the potential of future plantings to offset atmospheric carbon emissions. John Kort explained how this is accomplished, "Carbon emissions end up in the atmosphere as carbon dioxide, the main greenhouse gas. Plants take the carbon dioxide out of the air through photosynthesis using the carbon to build tissue and grow".
Kort and Turnock then set about taking samples of mature deciduous trees, coniferous trees and deciduous shrubs in 3 soil zones: the Black, Dark Brown and Brown. They took a number of shelterbelt measurements including the height and width of the rows and the moisture content of the trees. Based on these measurements, they were then able to do some calculations that showed that each species contains about 50% carbon. They were also able to calculate total carbon per tree and the amount of carbon per km of row of each species (Table 1).
Table 1. Carbon Content of Shelterbelt Trees and Shrubs.
|
Species |
Total C/tree (kg/tree) |
Total C (tonnes/km) |
|
Green ash |
125.2 |
62.6 |
|
Manitoba maple |
117.0 |
58.5 |
|
Hybrid poplar |
294.8 |
117.9 |
|
Siberian elm |
145.2 |
72.7 |
|
White spruce |
180.1 |
80.0 |
|
Scots pine |
113.1 |
62. 9 |
|
Colorado spruce |
147.8 |
82.2 |
|
Caragana |
29.1 |
38.9 |
|
Chokecherry |
35. 1 |
30.2 |
|
Villosa lilac |
29.2 |
25.1 |
|
Buffalo berry |
23.4 |
23.4 |
|
Sea-buckthorn |
14.6 |
16.1 |
Since hybrid poplar are fast growing trees and may have the greatest potential as a carbon sink, the Shelterbelt Centre, with support from Sask Power and local cooperators, is establishing several poplar plantations throughout Saskatchewan. The plantations will enable the researchers to study the growth of hybrid poplar, its value as a carbon sink and the feasibility of growing poplar as a source of wood.
The Shelterbelt Centre has been distributing trees since 1903. Since that time, over 500 million trees have been planted in prairie fields and farm yards. While it has been recognized for many years that field shelterbelts protect the soil from wind erosion, provide wildlife habitat and control blowing snow, Kort and Turnock have proven that trees offer one more very important benefit - growing trees are carbon sinks. The ability of trees to store significant amounts of atmospheric carbon enhance their value to both the farm and society.