VARIATIONS OF ELEMENT CONCENTRATIONS IN ROOTS OF DIFFERENT TREE SPECIES

Element concentrations of roots play an important role for plant growth and below ground biochemical cycles in forest ecosystems. It can show a change among species. This research aimed to determine changes in the nutrient content for different root diameters of trees in the Belgrad forest. Natural species of Sessile oak (Quercus petraea L.), Scots pine (Pinus sylvestris L.), Austrian pine (Pinus nigra Arnold.), Turkish fir (Abies bornmuelleriana L.), and Oriental spruce (Picea orientalis L.) were studied. Root sampling was carried out by randomly collecting twenty soil samples within each species once every three months (from April 2007) over one year. Roots were classified by fine root (5mm) diameter classes. Total concentration of elements (K, Ca, P, Fe, Mg, Cu, Mn, Al, Ni, Zn, Na) in each root classes were determined. The macro elements Mg, K, and P and all microelements in the included species showed a tendency to decrease in concentration with increasing root diameters. Macro elements except K and P and microelements except Pb, Al, Zn, and Cu showed a significant temporal difference between species based on the root diameters. Al, Pb, Ni, Mn, and Fe showed different antagonistic relations with Ca, Mg, P, and K between species with regard to their concentration in fine roots. There was no significant negative correlation between small and coarse roots in species (except in oak species). The results have shown that nutrient storage characteristics differ between different species in the same site

Temporal changes of soil respiration under different tree species

Soil respiration rates were measured monthly (from April 2007 to March 2008) under four adjacent coniferous plantation sites [Oriental spruce (Picea orientalis L.), Austrian pine (Pinus nigra Arnold), Turkish fir (Abies bornmulleriana L.), and Scots pine (Pinus sylvestris L.)] and adjacent natural Sessile oak forest (Quercus petraea L.) in Belgrad Forest-Istanbul/Turkey. Also, soil moisture, soil temperature, and fine root biomass were determined to identify the underlying environmental variables among sites which are most likely causing differences in soil respiration. Mean annual soil moisture was determined to be between 6.3 % and 8.1 %, and mean annual temperature ranged from 13.0A degrees C to 14.2A degrees C under all species. Mean annual fine root biomass changed between 368.09 g/m(2) and 883.71 g/m(2) indicating significant differences among species. Except May 2007, monthly soil respiration rates show significantly difference among species. However, focusing on tree species, differences of mean annual respiration rates did not differ significantly. Mean annual soil respiration ranged from 0.56 to 1.09 g C/m(2)/day. The highest rates of soil respiration reached on autumn months and the lowest rates were determined on summer season. Soil temperature, soil moisture, and fine root biomass explain mean annual soil respiration rates at the highest under Austrian pine (R (2) = 0.562) and the lowest (R (2) = 0.223) under Turkish fir

Effects of thinning on soil respiration and microbial respiration of forest floor and soil in an oak (Quercus frainetto) forest

The effects of tree thinning on soil respiration and microbial respiration in a Hungarian oak (Quercus frainetto Ten.) forest were examined over a 2-year period (2010-12). Tree density was reduced to 50% of the basal area. The research focus was on the main factors influencing the soil respiration (R-S) and microbial respiration in the forest floor (R-FFM) and in the soil (R-SM): soil temperature, moisture, carbon (C), nitrogen (N), and pH; groundcover biomass (GC); forest floor mass, carbon and nitrogen; and fine root biomass. R-S was measured twice monthly with the soda-lime method, and the incubation method was used to measure R-SM and R-FFM separately. The results were evaluated annually and over the 2-year research period. Correlation and stepwise regression analyses were used for statistical evaluation. Annual mean R-S was significantly higher in thinned plots (1.92gCm(-2)day(-1)) than in the control plots (1.79gCm(-2)day(-1)). Over the 2-year research period, R-S was higher in the thinned plots, and had linear correlations with GC, soil temperature and fine root biomass. GC was found to be the main factor that determined R-S. The control plots had significantly higher R-SM in first year, whereas the thinned plots had significantly higher R-SM in second year; no significant difference was found over the 2-year research period. R-FFM was significantly higher in the control plots than in the thinned plots, by 84% in the second year and by 34% over the 2-year study period. R-SM had a linear correlation with soil N content and soil pH, whereas R-FFM had linear correlations with C concentration and the C:N ratio of the forest floor in the thinned plots

Thinning effects on biomass and element concentrations of roots in adjacent hornbeam and oak stands in Istanbul, Turkey

Background Thinning is a commonly used treatment in forest management which affects the tree root systems. The effects of thinning on element concentrations and seasonal change of roots were evaluated in adjacent oak (Quercus frainetto Ten.) and hornbeam (Carpinus betulus L.) stands according to the different root diameter classes. Method Two replicated control and thinning plots (50 m x 50 m) were set for each species (hornbeam and oak). Thinning treatments (November 2010) reduced 50% of the basal area in both oak and hornbeam stands. Roots were assessed by seasonal collection over 2 years (from October 2010 to October 2012). The roots were then sorted into diameter classes of 0-2 mm (fine roots), 2-5 mm (small roots) and > 5 mm (coarse roots). C, N, P, K, Ca, Na, Mg, S, Mn, Fe, Al, Zn, Pb, Ni, Cu and Cd were analyzed. Results Except coarse roots, the highest root biomasses were determined in April-2011 in all plots. Fine-root biomass in oak was found significantly higher in control plots. In contrast to the oak, the fine-root biomass in the thinned hornbeam plots was higher than in the controls. The small-root biomass did not significantly differ between the thinned and the control plots in both oak and hornbeam stands. However, the coarse-root biomass showed significant differences between the control (1989 g center dot m(- 2)) and thinned plots (1060 g center dot m(- 2)) in oak, while no difference was detected in hornbeam. The concentrations of C, Al, Pb, Cd, Ni, Zn, Mn, Na, K, Mg and P in the fine roots of oak were significantly higher in the thinned plots. However, the concentration of Pb, Cd and Fe in the fine roots was significantly higher in the thinned plots of hornbeam. Significant differences were observed between the species for all elements in the fine roots except for C, N and P. In particular, elements in the fine roots tended to increase in July in the oak. In the hornbeam, all element concentrations in the fine roots (except C, N, and S) in the thinned plots showed a tendency to increase in April. The concentrations of Pb, Ni, Al, Fe, Cu, Ca, Na, K, Mg and P in the hornbeam control plots increased during the April 2011 period. Conclusion The results indicated that thinning effects on temporal changes and concentrations of elements in the roots could be attributed to species-specific characteristics