TCS Daily

Our Gift to Christmas Trees

By Robert C. Balling - December 22, 2003 12:00 AM

Like most of you, we have a new family member in the house decorated with lights, balls, angels, a star, and a miniature bullet train racing around its base. These trees get more attention than many children, and for the time they stay in our homes, they are literally part of the family with plenty of pictures to remember their time with us. Neighbors even stop by to tell us how beautiful our latest family member looks in the house... sound familiar?

Anyway, it is also the time of year to wonder if these precious pines will reap any significant biological benefits from the continued increase in atmospheric CO2. A trip to the library reveals another seven recent articles in the scientific literature on various pine trees with great news for the holiday season.


  • Greenep et al. grew pine trees in open-top chambers at near-ambient (360 ppm) and elevated (650 ppm) CO2 concentrations. They found that the photosynthetic rate in young needles increased by 38 percent in elevated CO2 levels while the rate increased by 41 percent in older needles. The water use efficiency of the trees increased by 49 percent in the higher CO2 chambers. (1)


  • Kainulainen et al. enclosed 22-year-old Scots pine trees for three years in open-top chambers with atmospheric CO2 concentrations of 350 and 600 ppm and ambient and elevated ozone concentrations. Their focus was not on the trees, but rather on the needle litter collected on the ground. The team found that elevated CO2 or ozone had no effect on the decomposition rate of Scots pine needles. Scrooges claim that elevated CO2 may disrupt soil nutrient cycling, but no such evidence appeared in their study. (2)


  • Kilpeläinen et al. exposed 15-year-old Scots pine trees in open-top chambers to ambient and elevated atmospheric CO2 and temperature with a focus on the properties of the resulting wood. They found that "Absolute radial growth over the 3-year period was 54% greater" due to elevated CO2 and 25 percent greater in trees with elevated CO2 and temperature. (3)


  • Sallas et al. grew Scots pine and Norway spruce seedlings for 50 days in environmental growth chambers with ambient and twice-ambient CO2 concentration and ambient and elevated temperatures. They observed the greatest growth rate in the chambers with the combined elevated CO2 and temperature treatment. (4)


  • Schafer et al. used numerical models and actual measurements in their study of Duke University's pine forest growing in ambient and elevated CO2 concentrations. While their study focused on testing the accuracy of numerical models, they found that that net ecosystem production increased by 44 percent under elevated CO2. (5)


  • Rathgeber et al. examined tree-ring chronologies from Aleppo pine trees in southeastern France to calibrate a numerical model of forest productivity. Given their estimates of future climate change in terms of temperature and precipitation, they predicted an increase of forest productivity from 17 to 24 percent. The effects of elevated CO2 alone increased productivity by 72 to 86 percent. But when climate change and elevated CO2 were considered together, the productivity of these pine trees increased by 107 to 141 percent! (6)


  • George et al. grew lobolly pines in ambient and elevated CO2 with a focus on the impact on fine-root growth (RG). The authors concluded "A substantial increase in fine-root production contributed to a 151% increase in RG for loblolly pine in elevated CO2." (7)


These many different pine trees, like the ones in our houses this season, believe in Santa Claus all right, and they cannot expect a greater gift from us than more atmospheric CO2. The evidence in the scientific literature is overwhelming, and evidence confirms the biological miracle that comes from higher levels of CO2.


Have a great holiday season.


(1) George, K., Norby, R.J., Hamilton, J.G., and DeLucia, E.H. 2003. Fine-root respiration in a loblolly pine and sweetgum forest growing in elevated CO2. New Phytologist, 160, 511-524.


(2) Greenep, H., Turnbull, M.H., and Whitehead, D. 2003. Response of photosynthesis in second-generation Pinus radiata trees to long-term exposure to elevated carbon dioxide partial pressure. Tree Physiology, 23, 569-576.


(3) Kainulainen, P., Holopainen, T., and Holopainen, J.K. 2003. Decomposition of secondary compounds from needle litter of Scots pine grown under elevated CO2 and O3. Global Change Biology, 9, 295-304.


(4) Kilpeläinen, A., Peltola, H., Ryyppö, A., Sauvala, K., Laitinen, K., and Kellomäki, S. 2003. Wood properties of Scots pines (Pinus sylvestris) grown at elevated temperature and carbon dioxide concentration. Tree Physiology, 23, 889-897.


(5) Rathgeber, C., Nicault, A., Kaplan, J.O., and Guiot, J. 2003. Using a biogeochemistry model in simulating forests productivity responses to climatic change and [CO2] increase: Example of Pinus halepensis in Provence (south-east France). Ecological Modelling, 166, 239-255.


(6) Schafer, K.V.R., Oren, R., Ellsworth, D.S., Lai, C.-T., Herrick, J.D., Finzi, A.C., Richter, D.D., and Katul, G.G.. 2003. Exposure to an enriched CO2 atmosphere alters carbon assimilation and allocation in a pine forest ecosystem. Global Change Biology, 9, 1378-1389.


(7) Sallas, L., Luomala, E.-M., Utriainen, J., Kainulainen, P., and Holopainen, J.K. 2003. Contrasting effects of elevated carbon dioxide concentration and temperature on Rubisco activity, chlorophyll fluorescence, needle ultrastructure and secondary metabolites in conifer seedlings. Tree Physiology, 23, 97-108.



TCS Daily Archives