The energy used and thus C emissions associated with
chemical herbicide manufacture are available for only a relative
small number of products. Helsel (1992) lists eight products
that include the forestry herbicides 2,4-D and glyphosate. These
products differ in C emissions associated with production
ranging from 0.7 to 3.9 kg C/lb (1.5 to 8.6 kg C/kg) of product.
In the case of herbicide application, rates can also vary broadly
and thus will affect total C emissions as will method of
application (i.e., aerial or ground, broadcast or banded)