Root Nutrition, Photosynthesis, and Net Primary Production in Tree Stands of the genus Picea at the Organism Level within the Range in Russia

A complex retrospective ecological and physiological analysis of the tabular data on the dry weight of stands of the genus Picea growing from the Northwest to the Russian Far East was carried out. Ecological and physiological indicators are calculated per an organism (conditional tree of average weight). Biological productivity (BP, times) was determined by the relative increase in the average dry weight of a tree in adjacent age periods. Quantitative data of mineral productivity (MP, mg/m2/per day) were found by the method of VM. Lebedev, and the net productivity of photosynthesis (NPPh, g/m2/per day) was calculated according to A.A. Nichiporovich at the organism level in stands of each age period in the range from 10–30 to 120–210 years. In all regions, there was a decrease in the element uptake by trees with age: nitrogen (N) by 14.9–93.7, phosphorus (P) by 18.7–119.9 and potassium (K) by 15.4–134.4 times. A sharp decrease in the element uptake continued until the age of 50–60 years, after which it stabilized at an extremely low level. The decline in the root uptake activity resulted in a 2.88–14.0 and 1.64–2.60-fold drop in NPPh and BP, respectively. The correlation between N, P and K uptake with NPPH and BP was highly positive in all zones. Within Russia in 30, 60, 90, and 120-year-old stands differences in the values of net primary production (NPP, g/m2 of nutrition area) reached 5.0, 4.7, 4.6, and 5.2 times, respectively, and net mineral productivity by nitrogen (NMP(N), g/m2 of nutrition area) reached 4.0, 4.3, 4.8, and 4.6 times, respectively. The correlation between these two indicators was described as highly positive. The correlation between the amount of nitrogen uptaken by spruce roots and the efficiency of its use in forming a unit of biomass was highly negative in all regions. The center of the Russian Plain and the Middle Volga region were the best regions for the growth of spruce plants, while the Krasnoyarsk and Khabarovsk (north) Krais were the worst.