Attachment I Description of Project.docx

ATTACHMENT I

THE NORTHERN FOREST ECOSYSTEM EXPERIMENT

The Northern Forest Ecosystem Experiment (NFEE) is a long-term, large-scale manipulative experiment designed to study the effects in increasing concentrations of carbon dioxide and ozone on naturally regenerating trembling aspen forests. The experiment resides on a secure, 32 ha site operated by the Northern Research Station’s Institute for Applied Ecosystem Studies (IAES) located at the USFS Harshaw Research Farm in Oneida County, Wisconsin. It consists of twelve, 30 m diameter rings formed from PVC pipes which encircle model forests of pure trembling aspen, aspen mixed with paper birch, and aspen mixed with sugar maple. Each of the twelve rings receives on of four experimental treatments: control (current ambient air), or ambient air enriched with CO2, O3, or both CO2 and O3. Thus, each of the four treatments is replicated three times.

The CO2 and O3 gasses are dispersed into the treatment plots by a series of 32, independently valved, vertical vent pipes surrounding each ring. Gas concentrations are regulated by computer-controlled mass flow controllers. The gasses are delivered to each ring via copper or stainless steel pipe for CO2 and O3, respectively, from a centralized storage and supply facility at the site. Ozone is manufactured on-site from pure oxygen with a commercial ozone generator. Liquid oxygen is stored in a 3000 gallon storage tank and vaporized with an ambient air heat exchanger. Liquid CO2 is also stored on-site in two, 55 ton receiver tanks, and is vaporized by two banks of four ambient air vaporizer towers.

The Forest Service seeks to purchase liquid CO2, delivered by truck to the research site, and rent the CO2 storage and supply equipment. The purveyor will provide:

a) About 2200 tons of liquid carbon dioxide as needed from mid May 2010 until mid October 2010. This usage estimate is conservative. The actual amounts purchased will depend entirely upon usage. The actual amount of CO2 used will depend upon the number of days leaves are on the trees, and weather. The dates of usage are approximate and depend entirely upon the timing of spring sprouting and autumn leaf senescence of the experimental trees.

b) On-site liquid carbon dioxide storage and supply equipment, which includes the on-site storage tanks, ambient-air vaporizer towers, and associated pipes and other equipment.

c) The CO2 delivered must meet specific chemical requirements regarding the relative abundances of the two carbon isotopes, carbon-12 (12C) and carbon-13 (13C). Delivered CO2 must have 13C between -8 and -10 o/oo (Footnote 1). The 13C of CO2 deliveries will be verified by laboratory analysis by the IAES or their research collaborators.

Delivery location:

Harshaw Research Farm 4398 Grace Ln.

Harshaw, WI 54529

On-Site Phones: 715- 282-7240 (Site Operator’s office) 715-181-7509 (Karnosky Laboratory)

Footnote 1.

The two stable (non-radioactive) isotopes of carbon 12C and 13C comprise the bulk of CO2 molecules. Isotopes are simply atoms of a particular element that contain differing numbers of protons and neutrons in the nucleolus. Thus, for carbon, 12C has twelve neutrons and protons, and 13C and one additional neutron. In the natural environment, 12C is by far the most abundant carbon isotope. Because 13C has more mass than 12C, it enters into chemical processes more slowly than does 12C. Thus, various chemical processes are said to discriminate against 13C. Different chemical processes, including those in both biological and industrial systems, have varying degrees of 13C discrimination. Consequently, CO2 that is produced from various biological and industrial systems has varying abundances of 13C.

The ratio of 13C to 12C in any substance is described relative to that of a universal standard. One usual standard is the 13C/12C ratio that occurs in certain fossilized cephalopods (belemnites) found in the Cretaceous Pee Dee shale formations in South Carolina (referred to as the Pee Dee Belemnite, or PDB standard). The 13C/12C of the PDB standard is 0.0112372. The notation used to express this comparison is the lower-case Greek letter Delta (), and is expressed in terms of parts per thousand, i.e., per mil (o/oo). Substances with 13C/12C less than that of the PDB standard have values less than zero, and those with 13C/12C greater than the standard have values greater than zero. For example, current ambient air has 13C = -8 o/oo.