Lopatin, E. 2007. Long-term trends in height growth of Picea obovata and Pinus sylvestris during the past 100 years in Komi Republic (north-western Russia). Scandinavian Journal of Forest Research 22: 310-323.
What was done
Working in the Komi Republic of northwestern Russia, where large areas of natural boreal forest still exist, the author analyzed the apical growth history of 108 Scots pine (Pinus sylvestris L.) and 88 Siberian spruce (Picea obovata Ledeb.) trees via cohort comparison, whereby "differences in average height growth curves between trees with different germination dates were used as indicators [of] changes in forest site productivity over time," focusing on two age classes: 1900-1949 and 1950-2000, based on year of germination.
What was learned
Lopatin reports that "statistically significant height increment increases were found in the middle taiga zone for Siberian spruce of 240% and Scots pine of 140%, while northern taiga Siberian spruce increased by 164%. For the entire Komi Republic (the forested area of which comprises 33% of northwest Russia's total forest area), he further states that "a statistically significant increase in height increment of 40% for Siberian spruce and 30% for Scots pine was identified."
What it means
Taking account of the fact that "trees were sampled in remote untouched pristine forests," Lopatin writes that "the main causes of increased height increment are suggested to be climatic," noting there was "a large increase in temperature (0.43°C during the past 30 years)," to which we would merely add that the atmosphere's growth-promoting CO2 concentration rose by close to 50 ppm over the same period. Hence, it would appear that the "twin evils" of the radical environmentalist movement (rising air temperatures and atmospheric CO2 concentrations) have been nothing but good for the boreal forests of the Komi Republic.
Also of note is the fact, as described by Lopatin, that "the directions and magnitude of observed trends in this study were opposite [our italics] to the decline in annual radial increment during the century (Briffa et al., 1998a) in the northern hemisphere, including Russia." He suggests that this discrepancy "is possibly due to the sensitivity problem (Briffa et al., 1998b), which appears to arise mainly because the dendroclimatic methods used [by Briffa et al.] were unable to cope with large increases in growth rate," such as those detected in the Komi Republic in Lopatin's study; and he adds that "the discrepancies between a satellite-observed increase in NDVI [normalized difference vegetation index] and decrease in radial increment over Eurasia [as found by Briffa et al.] could be clarified by analyzing height increment with annual resolution," as he did in the Komi Republic study, and which he feels is "a better approach."
Briffa, K.R., Schweingruber, F.H., Jones, P.D., Osborn, T.J., Harris, I.C., Shiyatov, S.G. et al. 1998a. Trees tell of past climates: But are they speaking less clearly today? Philosophical Transactions of the Royal Society of London Series B, Biological Sciences 353: 65-73.
Briffa, K.R., Schweingruber, F.H., Jones, P.D., Osborn, T.J., Shiyatov, S.G. and Vaganov, E.A. 1998b. Reduced sensitivity of recent tree-growth to temperature at high northern latitudes. Nature 391: 678-682.Reviewed 30 January 2008