Changes to the US Renewable Fuel Standard Program:

Petition for an Aggregate Compliance Approach 

for Canadian Crops and Crop Residues

Procedure and Rationale for Trend Analysis used in 

Data Comparability, Analysis and Justification

Estimates for Pastureland

The annual surveys of field crops and hays (as mentioned in Section 3 of Canada’s 

petition, page 4) do not collect information on land area segregated for tame or seeded 

pasture (pastureland). Annual crop surveys collect information on land for pasture, 

which includes all categories of land in pasture (such as tame/seeded pasture and 

rangeland) and does not segregate pastures by type. Furthermore, the objective of the 

sample design of annual crop surveys is to estimate field crop areas and yields. As a 

result, the quality of estimates for total land in pasture often falls below Statistics 

Canada’s data quality standards, and therefore, the estimates are not published. 

In order to estimate tame or seeded pasture acreage in 2007, the data on tame or seeded 

pasture are obtained from the past 5 Censuses of Agriculture from 1986 to 2006 and 

analyzed for the trend. First, the acreage of tame or seeded pasture for these census years 

is regressed on a constant and a simple linear time trend T, where T varies from 1 to 5 

with 1 representing the earliest census year (1986) and 5 representing the latest census 

year (2006) in the census cycles covered in the analysis. The results show that the data 

fitted very well to the linear regression model (Chart 1 and the Summary Output in the 

attached Excel file). The adjusted R-square value of the regression, which is a measure 

of the goodness of fit of data in the regression model and the power of the model in 

predicting future outcomes, is 0.9367. In other words, the estimated regression 

coefficients are capable of explaining about 94% of the variability in the data.

Estimates (Estimate_1 on the worksheet “PastureEst” in the attached Excel file) for the 

years between census cycles are derived by adding the immediate past census year’s data 

to the coefficient of the time trend (T) distributed over the years between two successive 

census years (i.e., the coefficient divided by 5). Following the standard practice of 

benchmarking survey estimates for the census years with the census data, the census 

acreages for tame or seeded pasture are kept unchanged as benchmarks. 

The annual estimates thus derived have not been smooth over the years. Therefore, a 

second set of annual estimates (Estimate_2 in the attached Excel file) is derived by

distributing the difference in acreage between two successive censuses over the years 

within the two censuses. In distributing the differences between 2001 and 2006, both 

current and immediate past period’s differences have been accounted for at a ratio of 2:1 

to keep the estimates at a lower level. The same factor has been used for extrapolating 
the acreage beyond 2006 to derive Estimate_2 for the years 2007-2010. As evident in 

Chart 2 in the attached Excel file, the Estimate_1 and Estimate_2 virtually overlap in all 

years except the periods 1993-1995 and 2004-2005, and tend to diverge slightly at the 

end (i.e., after 2008). To avoid higher and lower estimates, a simple average of 

Estimate_1 and Estimate_2 is taken to derive Estimate_3, which has been used as the 

final estimate in Table 5 of Canada’s petition.

For EPA’s annual evaluation, annual estimates (Estimate_3) for tame or seeded pasture 

areas will be derived from the model. After the publication of census data on tame or 

seeded pasture in the year following the census year (e.g., 2011 data will be available in 

2012), the estimates will be validated with the census data, and if necessary, the model 

will be reviewed and re-adjusted. 

Estimates for Christmas tree

Statistics Canada began collecting data for Christmas tree through the annual survey of 

greenhouse, sod and nursery in 2008. However, the area data for Christmas tree acreage 

is not published as the sample frame covers only a subset of farms producing Christmas 

tree (i.e., only greenhouse and nursery operations that also produce Christmas tree). 

To estimate the Christmas tree, sod and nursery acreage for 2007, the land area data for 

Christmas tree are obtained from the Censuses of Agriculture. Annual data for Christmas 

tree for the years between censuses have been derived by equally distributing the 

difference in acreage between two successive censuses over the years within the two 

censuses (Worksheet “XmasTr” in the attached Excel file). The data on sod and nursery

acreages have been obtained from annual survey1results for years 1997 to 2010, except 

for 2007, the year for which the data was not published. The sod and nursery acreage for 

1996 has been taken from the census data, while that for 1995 has been obtained by

subtracting one-fifth of the difference in acreage between 1996 and 2001 from the 1996 

acreage. The sod and nursery acreage for 2007 has been estimated as a simple average of 

2006 and 2008 data. 

The total acreages for Christmas tree, sod and nursery thus estimated remained 

unchanged at 0.2 million acres since 1995 mainly due to its lower magnitude and the 

rounding of decimal points. Therefore, this number is expected to remain unchanged over 

the short and medium term. 

Following the same procedure, annual estimates for Christmas tree, sod and nursery

acreage will be derived for EPA’s annual evaluation. 

 

1 There is a lag of one year in nursery and sod survey data collection and publication. The data for the past 

year are collected through the current year’s survey.