Ender Makineci

Temporal variations of biomass, carbon and nitrogen of roots under different tree species

Abstract Seasonal changes of root biomass, concentrations and masses of carbon and nitrogen in roots and root diameter classes (<2mm, 2–5mm and>5mm) were evaluated under four adjacent coniferous plantation sites: Oriental spruce (Picea orientalis L.), Austrian pine (Pinus nigra Arnold), Turkish fir (Abies bornmulleriana L.), Scots pine (Pinus sylvestris L.) and natural Sessile oak (Quercus petraea L.) forest. The root biomass, carbon and nitrogen concentrations, carbon and nitrogen masses, C/N ratio of roots were evaluated with regards to species, root diameter classes and seasons. The significantly (p<0.05) lowest annual mean root biomass was 258 g/m2 in Austrian pine compared with tree species. The fine root class has significantly the lowest carbon content, with the 42% value, among other root diameter classes. However, the temporal variations of root C (%) presented no statistical significance. The annual mean nitrogen concentrations ranged from 0.56% (Turkish fir) to 0.74% (Austrian pine) among species. We also found that root nitrogen concentrations in January were significantly different from those of other sampling times. C/N ratios showed statistically significant differences in root diameter classes that the ratios were found, 49 for fine roots, 111 for small roots and 143 for coarse roots, respectively.

Plant Species Recovery on a Compacted Skid Road

This study was executed to determine the plant species of herbaceous cover in a skid road subjected to soil compaction due to timber skidding in a beech (Fagus orientalis Lipsky.) stand. Our previous studies have shown that ground based timber skidding destroys the soils extremely, and degradations on ecosystem because of the timber skidding limit recovery and growth of plant cover on skid roads. However, some plant species show healthy habitat, recovery and they can survive after the extreme degradation in study area. We evaluated composition of these plant species and their cover-abundance scales in 100 m x 3 m transect. 15 plant species were determined belongs to 12 plant families and Liliaceae was the highest representative plant family. Smilax aspera L., Epimedium pubigerum (DC.) Moren et Decaisne, Carex distachya Desf. var. distachya Desf., Pteridium aquilinum (L.) Kuhn., Trachystemon orientalis (L.) G. Don, Hedera helix L. have the highest cover-abundance scale overall of determined species on compacted skid road.

Variations in carbon and nitrogen ratios and their effects on seed germination in Cupressus sempervirens populations

This study investigated the variations in the carbon (C), nitrogen (N), and C/N ratios in the seeds of the Mediterranean Cypress (Cupressus sempervirens L.), a typical forest tree of the Mediterranean Region. The data were gathered from populations distributed across Turkey. We also evaluated the relationship between these variations and germination parameters such as the germination percentage (GP) and mean germination time (MGT). All of the evaluated characteristics demonstrated statistically significant variations among the populations. The GPs were generally low and varied between 14% in Datça and 51% in the Köprülü Kanyon. The MGTs ranged from 14.9 in the Köprülü Kanyon to 18.9 in Marmaris. In addition, the C ratios varied between 46% in Marmaris and 52% in the Köprülü Kanyon, while the N ratios ranged from 1.1% in Beycik and Göksu to 1.8% in the Köprülü Kanyon. Furthermore, we observed a positive correlation between the GP and the C and N contents (R2 = 0.51 and R2 = 0.49, respectively) but found a negative correlation between the MGT and the C and N contents (R2 = 0.56 and R2 = 0.32, respectively). Moreover, with regard to the combined C and N seed ratios of the regression models, R2 = 0.95 for the GP and R2 = 0.87 for the MGT, and the populations with higher quantities of C and N in their seeds had shorter MGTs and higher GPs.

Estimating the age-dependent changes in carbon stocks of Scots pine (Pinus sylvestris L.) stands in Turkey

Abstract• Key messageSimulated and observed carbon stocks in Scots pine forests varied considerably with stand age. The contribution of biomass to the total forest carbon stocks increased and that of dead organic matter decreased with increasing stand age.• Context Understanding changes in forest carbon stocks over time is important to estimate carbon inventory. Although Scots pine (Pinus sylvestris L.) is a main species in Turkey, studies on such changes are still lacking.• Aims We aimed to estimate the changes in carbon stocks, with stand age, of Scots pine stands in Turkey using field work data and a forest carbon model (FBDC model).• Methods Biomass and dead organic matter carbon stocks were investigated to adjust the forest carbon model and to verify the model estimates. Forest carbon stocks with regards to stand age were simulated.• Results The simulated carbon stocks were generally in clear agreement with the observed values on a stand scale. Changes in simulated and observed carbon stocks of biomass and dead organic matter varied with stand age. The contribution of biomass to total forest carbon stocks increased, and that of dead organic matter decreased, with increasing stand age.• Conclusion We found that the carbon stocks in each pool and their contribution to the total forest carbon stocks varied with stand age. Our results are expected to contribute to the understanding of annual changes in the carbon stocks of Turkish forests.

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 (RS) and microbial respiration in the forest floor (RFFM) and in the soil (RSM): soil temperature, moisture, carbon (C), nitrogen (N), and pH; groundcover biomass (GC); forest floor mass, carbon and nitrogen; and fine root biomass. RS was measured twice monthly with the soda-lime method, and the incubation method was used to measure RSM and RFFM 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 RS was significantly higher in thinned plots (1.92 g C m–2 day–1) than in the control plots (1.79 g C m–2 day–1). Over the 2-year research period, RS 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 RS. The control plots had significantly higher RSM in first year, whereas the thinned plots had significantly higher RSM in second year; no significant difference was found over the 2-year research period. RFFM 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. RSM had a linear correlation with soil N content and soil pH, whereas RFFM had linear correlations with C concentration and the C : N ratio of the forest floor in the thinned plots.

Effects of parent material, stand type and oak species on defoliation of coppice-originated oak (Quercus spp.) forests in Northern Turkish Thrace

Cases of significant defoliation in oak (Quercus spp.) forests have been reported in Turkey and throughout the world. Oak trees are important in Turkish forests and forestry and cover vast pieces of land in Thrace. In this study, in a quest to determine the general health condition of pure oak forests in Northern Turkish Thrace, the defoliation rate of tree crowns was evaluated for 8,769 trees in 336 sample plots corresponding to different geological parent materials, regions, oak species and stand types. The defoliation rates were designated and assessed based on the criteria of the European Union Forest Health Monitoring Program (UNECE-ICP Forests). The defoliation rate was, to a significant extent, affected by stand type, the geological parent material, and oak species. In general, 47 % of trees exhibited defoliation. The highest ratio of defoliation was found in Kirklareli Region, where water deficit was the highest, and the parent material was schist-calcschist. Medium diameter forests (MDF, mean dbh: 8-20 cm, ratio of defoliated trees = 65 %) among stand types, and sessile oaks (ratio of defoliated trees = 53 %) among oak species, had the highest defoliation rates. Achieved results demonstrated that the defoliation classes in observed oak stands have a significant relation with variables concerning stand types, oak species and geological parent materials.

Estimating the effect of abandoning coppice management on carbon sequestration by oak forests in Turkey with a modeling approach

A significant area of the oak forests in Turkey has been historically managed by short-rotation coppicing for wood production. Coppice management was almost abandoned in Turkey in 2006 and so investigating its impact on forest carbon (C) sequestration has become an important issue. Therefore, we investigated the net effect of this change in management on C sequestration by oak forests in Turkey using field measurement data and a forest C model (Forest Biomass and Dead organic matter Carbon (FBDC) model). The FBDC model estimated the annual forest C dynamics and considered the effect of the substitution of wood for fossil fuels under two management scenarios over a 100-year period: (1) abandoning coppice (no management) and (2) continuing coppice (20-year-interval harvest). The field measurement data were used to parameterize the FBDC model to the study sites and to verify the simulated C stocks. Continuing coppice management constrained an increase in the C stocks (116.0-140.3 Mg C ha-1) and showed a mean annual C sequestration of 0.6 Mg C ha-1 yr-1 if wood was substituted for fossil fuels. In contrast, abandoning coppicing practices increased the level of forest C stocks (128.1-236.2 Mg C ha-1), enhancing the mean annual C sequestration to 1.1 Mg C ha-1 yr-1. Accordingly, the abandonment of coppice management increased the mean annual C sequestration by 0.5 Mg C ha-1 yr-1 in the long-term. However, sensitivity analysis showed a possibility of a larger difference in C sequestration between the two scenarios due to a decrease in the stand productivity by repeated coppices and a high likelihood of a lower substitution effect. The verification supported the scientific reliability of the simulation results. Our study can provide a scientific basis for enhancing C sequestration in coppice forests.

Seasonal and altitudinal variations of soil arthropods in Abies nordmanniana subsp. bornmulleriana forests

Seasonal and altitudinal variations in the abundance and diversity of soil arthropods were investigated in a pure Abies nordmanniana subsp. bornmulleriana (Uludag fir) forest ecosystem. Sample plots were set at three different altitudes (1,200 m, 1,400 m and 1,550 m), and samplings were performed in four seasons in February, May, August and November in 2010. Soil properties varied significantly among the seasons; higher soil nitrogen (N) and carbon (C) concentrations were found in summer while C/N ratio and pH were higher in autumn. Litter mass decreased from winter to summer; however, litter nitrogen concentration was inversely correlated with litter mass. Litter C/N, potassium and magnesium concentrations were different among the seasons although litter pH, carbon, phosphorus and calcium concentrations did not show significant differences. Soil pH, phosphorus, calcium and magnesium concentrations mainly showed a decreasing trend with altitude; however, soil nitrogen and carbon concentrations had a significantly increasing trend. Litter mass did not have any significant difference although litter pH, calcium and magnesium concentrations showed a significantly decreasing trend with altitude. In total, 54,348 individual soil arthropods were counted, identified and classified from 144 litter and soil samples collected in the study. The arthropods that were identified belonged to 90 different taxa within six classes and 28 orders, which were significantly different depending on habitats (soil or litter), altitudes and seasons throughout the year.

Abundance of Apodemus spp. varies by stand age in coppice-originated oak forest, Thrace, Turkey

Recently, oak (Quercus spp.) management strategies in Turkey have transitioned from predominantly coppice-regeneration to seed regeneration. However, impacts of this change on the small mammal community is unknown. To address this issue we evaluated abundance of Apodemus spp. (Rodentia, Muridae) in relation to stand age and forest characteristics in the northern Thrace, Turkey. We sampled 43 plots using box-style live traps. A total of 75 individuals (0.125 ± 0.013 mice/trap nights) was captured. Apodemus flavicollis (n = 69) was the most abundant, although A. agrarius (1) and A. sylvaticus (4) also occurred. Apodemus spp. abundance was superior in older than in younger stands (P = 0.038). The number of specimens was positively related to diameter at breast height (DBH) (y = 0.18 + 0.015x, R2 = 0.21) and forest floor mass (y = 0.005 + 0.00005x, R2 = 0.22). Increasing the amount of forest floor mass and mast production will benefit the population of Apodemus spp. Abandonment of the coppice management on oak forests in Thrace may positively affect the local abundance of Apodemus spp., particularly A. flavicollis.

Effects of carbon and nitrogen content on seed germination of calabrian pine (Pinus brutia) populations

Semillas de pino de Calabria (Pinus brutia) recolectadas de 15 poblaciones fueron analizados en su contenido de carbono (C) y nitrogeno (N). Ademas fueron evaluados los porcentajes de germinacion (GP) y tiempos medios de germinacion (MGT) de las semillas segun sus concentraciones de carbono y nitrogeno, relacion C/N, masa total de carbono (CM) y masa total de nitrogeno (NM). Excepto en las relaciones C/N, las variables mostraron diferencias significativas entre las poblaciones. La mayor concentracion de carbono de las semillas fue de 54 %, y la mas baja fue de 50 %. Las concentraciones de nitrogeno en las semillas variaron de 2,6 a 3,2 %. Las correlaciones mas altas se encontraron entre el GP de las semillas estratificadas (GPFS) y las concentraciones combinadas de carbono y nitrogeno (R2 = 0,65), y entre los GPFS y concentraciones de carbono (R2 = 0,63), ambas significativas. Las relaciones entre los parametros de germinacion y las concentraciones combinadas de carbono y nitrogeno, asi como los rasgos CM y NM fueron generalmente mayores que cualquiera de las evaluaciones individuales, a excepcion de las concentraciones de carbono.