Needle-age related variability in nitrogen, mobile carbohydrates, and δ13C within Pinus koraiensis tree crowns.

For both ecologists and physiologists, foliar physioecology as a function of spatially and temporally variable environmental factors such as sunlight exposure within a tree crown is important for understanding whole tree physiology and for predicting ecosystem carbon balance and productivity. Hence, we studied concentrations of nitrogen (N), non-structural carbohydrates (NSC = soluble sugars + starch), and δ(13)C in different-aged needles within Pinus koraiensis tree crowns, to understand the needle age- and crown position-related physiology, in order to test the hypothesis that concentrations of N, NSC, and δ(13)C are needle-age and crown position dependent (more light, more photosynthesis affecting N, NSC, and δ(13)C), and to develop an accurate sampling strategy. The present study indicated that the 1-yr-old needles had significantly higher concentration levels of mobile carbohydrates (both on a mass and an area basis) and N(area) (on an area basis), as well as NSC-N ratios, but significantly lower levels of N(mass) (on a mass basis) concentration and specific leaf area (SLA), compared to the current-year needles.

Soil respiration in relation to photosynthesis of Quercus mongolica trees at elevated CO2.

Knowledge of soil respiration and photosynthesis under elevated CO(2) is crucial for exactly understanding and predicting the carbon balance in forest ecosystems in a rapid CO(2)-enriched world. Quercus mongolica Fischer ex Ledebour seedlings were planted in open-top chambers exposed to elevated CO(2) (EC = 500 µmol mol(-1)) and ambient CO(2) (AC = 370 µmol mol(-1)) from 2005 to 2008. Daily, seasonal and inter-annual variations in soil respiration and photosynthetic assimilation were measured during 2007 and 2008 growing seasons.

[Spatial heterogeneity of soil inorganic nitrogen in a broadleaved-Korean pine mixed forest in Changbai Mountains of northeast China].

Geostatistic methods were applied to study the spatial heterogeneity of top soil (0 - 10 cm) ammonium N and nitrate N in a broadleaved-Korean pine mixed forest of Changbai Mountains, Northeast China. The semi-variogram of soil ammonium N and nitrate N could be well fitted by spherical or Gaussian model. The spatial distribution of soil ammonium N and nitrate N all exhibited moderate autocorrelation, with the structural ratio being 0.

[Woody plant fine root biomass and its spatial distribution in top soil of broad-leaved Korean pine forest in Changbai Mountain].

Geostatistic method was applied to study the spatial distribution of woody plant fine root biomass in a natural broad-leaved Korean pine (Pinus koraiensis) mixed forest soil in Changbai Mountain. The investigation was carried out in three selected plots, sized 50 m x 50 m, in 2008. In the three plots, the living fine root biomass in surface soil (0-20 cm) was 3.