Jaeyeob Jeong

Carbon storage and soil CO2 efflux rates at varying degrees of damage from pine wilt disease in red pine stands.

We evaluated the carbon (C) storage and soil CO2 efflux rates of red pine (Pinus densiflora S. et Z.) stands damaged by pine wilt disease (PWD) in Korea. Ten red pine plots at varying degrees of damage from PWD were established and grouped into five categories (very slightly, slightly, moderately, severely, and very severely damaged plots) based on differences in the tree density. The incidence of PWD was a major cause of C loss from forest ecosystems, but the magnitude of loss depended on the severity of disease damage. An exponential regression of the CO2 efflux rates against the corresponding soil temperature was highly significant (R(2)=0.82-0.95, P<0.01) for the varying degrees of damage from PWD. The rates of change in the CO2 efflux rates with temperature, as defined by the Q10 values, were generally lower in the slightly (2.94) versus the moderately (3.60) or severely (4.26) PWD-damaged stands. The cumulative soil CO2-C efflux rates for two years were significantly higher in the slightly (10.8 Mg Cha(-1) yr(-1)) or moderately (10.9 Mg Cha(-1) yr(-1)) versus the very severely (7.9 Mg Cha(-1) yr(-1)) PWD-damaged stands. The results indicate that the C storage and soil CO2 efflux rates in red pine stands can be impacted by the incidence of PWD, with a significant C reduction in the severely damaged stands.

Influence of forest tending (Soopkakkugi) works on litterfall and nutrient inputs in a Pinus densiflora stand

This study was conducted to examine litterfall and nutrient inputs following forest tending works (FTW) which are one of the most important forest management activities in Korea. We measured litterfall and nutrient (C, N, P, K, Ca, Mg) inputs from needle litter in FTW and non-FTW (control) stands of approximately 40-year-old red pine (Pinus densiflora S. et Z.) forests in the Hwangmaesan Soopkakkugi model forest in Sancheonggun Gyeongsangnam-do, Korea. Seasonal inputs of litterfall components such as needle, broadleaf, branch, bark and total litter inputs followed a similar pattern between the FTW and control stands. Annual average needle and total litterfall were significantly lower in the FTW (2483 kg ha−1 yr−1; 4038 kg ha−1 yr−1) than in the control stands (3377 kg ha−1 yr−1; 5589 kg ha−1 yr−1) during the study period. Nitrogen concentration of needle litter was significantly affected by FTW (P < 0.05), while other nutrient (C, P, K, Ca, Mg) concentrations were not significantly different between the FTW and control stands. There was a significant difference (P < 0.05) in the organic C, N, P and Ca inputs by needle litter following FTW, whereas K and Mg inputs were not significantly different between the FTW and control stands. The results indicate that the reduction of litterfall and nutrient inputs following FTW can be attributed to reduced needle litterfall and vary considerably nutrient cycle in FTW stands.

Relationships between Litterfall Amounts and Stand Attributes in a Quercus accutissima Stand

This study was carried out to evaluate the relationships between stand attributes and litterfall amounts in a 28-year old Quercus acutissima stand. Eighteen sampling plots of were chosen and litterfall was collected from May 2005 to December 2006. There was no correlation between stand attributes(tree density, mean diameter at breast height, mean height, basal area) and litterfall amounts except for flower and miscellaneous litter for the study period. There were no significant relationships between leaf litter and basal area(r

Litter decomposition and nutrient dynamics following forest tending (Soopkakkugi) works in a Pinus densiflora stand

This study was conducted to determine mass loss rates and nutrient dynamics from decomposing litter following forest-tending (Soopkakkugi) works (FTW) which are one of the most important forest management activities in Korea. We measured litter decomposition rates for 2 years in FTW and non-FTW (control) stands of approximately 40-year-old red pine (Pinus densiflora S. et Z.) forests in the Hwangmaesan Soopkakkugi model forest in Sancheonggun Gyeongsangnam-do, Korea. Mass loss rates from decomposing needle litter were significantly lower (P < 0.05) in the FTW than in the control stands for three of the six sampling dates during the study period. Nutrient concentrations and nutrients remaining such as carbon, nitrogen, phosphorus, potassium, and magnesium from decomposing litter were significantly different (P < 0.05) between the FTW and control stands because of decreased mass loss rates by increased gaps following FTW. The results indicate that FTW clearly influence litter decomposition and nutrient dynamics from decomposing needle litter because of the change of environmental factors caused by partial canopy removal such as FTW.

Carbon and nitrogen status in litterfall of a red pine stand with varying degrees of damage from pine wilt disease

We evaluated the carbon (C) and nitrogen (N) status of litterfall in a natural red pine (Pinus densiflora ) stand damaged by pine wilt disease in Jinju City, which was one of the areas severely affected by the disease in Korea. A significant cor relation (P < 0.05) was found between tree density and basal area and the C and N status of litterfall components, but C and N status was not correlated with mean diameter at breast height in the pine wilt disease stands. Needle-litter C and N concentrations were linearly related (P < 0.05) to basal area in pine wilt disease stands. Needle-litter C concentration decreased with a decrease in damage intensity due to pine wilt disease, whereas litter N concentration increased with an increase of basal area in pine wilt disease stands. The linear regression equations developed for litterfall C and N inputs were significant ( P < 0.05), with basal area accounting for 50-86% of the variation, except for cone and flower litter. The results indicated that the incidence of pine wilt disease could impact the quality and quantity of C and N in litterfall of pine stands suffering from pine wilt disease.

Effects of Forest Tending Works on Carbon Storage in a Pinus densiflora Stand

We conducted research to determine the effects of forest tending works (FTW) on forest carbon (C) storage in Korean red pine forests by estimating changes in the quantity and distribution of stored organic C in an approximately 40-year-old red pine stand after FTW. We measured organic C storage (above- and belowground biomass C, forest floor C, and soil C at 50 cm depth) in the Hwangmaesan Soopkakkugi model forest in Sancheonggun, Gyeongsangnam-do before and after the forest was thinned from a density of 908 trees/ha to 367 trees/ha. The total C stored in tree biomass was 69.5 Mg C/ha before FTW and 38.6 Mg C/ha after FTW. The change in total C storage in tree biomass primarily resulted from the loss of 19.9 Mg C/ha stored in stem biomass after FTW. The total C pool in this red pine stand was 276 Mg C/ha before FTW and 245.1 Mg C/ha after FTW. Prior to FTW, 71.5% of the total C pool was stored in mineral soil, 25.2% in tree biomass, and 3.3% in the forest floor, where as after FTW 80.5% of the total C pool was stored in mineral soil, 15.7% in tree biomass and 3.7% in the forest floor. These results suggest that the development of site-specific tending techniques may be required to minimize the loss of tree biomass C storage capacity in red pine stands from FTW.

Nutrient dynamics by decomposing leaf litter at the Guemsan (Mt.) Long-Term Ecological Research site, Korea

Litter decomposition represents a major contribution to the carbon and nutrient fluxes in forest ecosystems. Nutrient dynamics from decomposing leaf litter were measured for 3 years (1095 days) from three dominant tree species (Quercus serrata, Carpinus laxiflora, Carpinus cordata) in a broadleaved deciduous forest of the Geumsan (Mt.) Long-Term Ecological Research (LTER) site in Korea. Mass loss rates from decomposing leaf litter were significantly lower in the Q. serrata leaf litter (63.4% of the original mass) than in C. laxiflora (80.0%) and C. cordata (83.1%) leaf litter over 1095 days. There was a significant linear relationship between the remaining mass of leaf litter and the incubation months of litterbag (Q. serrata: r2 = 0.96; C. laxiflora: r2 = 0.96; C. cordata: r2 = 0.95). Nitrogen and phosphorus concentrations (mg g−1) and remaining stocks (mg bag−1) from decomposing leaf litter were significantly lower in Q. serrata leaf litter than in C. laxiflora and C. cordata leaf litter during the study period. Calcium and magnesium concentration and remaining stocks of initial stage from decomposing litter were significantly higher in C. cordata leaf litter than in that of C. laxiflora and Q. serrata. However, potassium concentration and remaining stocks were not affected by the three leaf litter types. The results indicate that Carpinus spp. (C. laxiflora, C. cordata) leaf litter is a significant and easily decomposable source of nutrients among dominant tree species of a mixed broadleaved deciduous forest in the Geumsan LTER site.

Distribution of carbon and nitrogen in forest floor components in Pinus radiata plantations of different ages in South Australia

ABSTRACT This study was conducted to evaluate the effects of plantation age on the distribution of carbon (C) and nitrogen (N) in forest floor components in radiata pine (Pinus radiata D. Don) plantations. Forest floor samples from plantations of three age classes (13-year-old; 27-year-old; 41-year-old) with various site qualities (II–VII) were collected from the Kuitpo radiata pine plantations in the Mount Lofty forest region of South Australia. The C concentrations of the forest floor components were significantly higher in the 41-year-old plantation than in the 13-year-old plantation, whereas the N concentrations were significantly lower in the 41-year-old plantation than in the 13-year-old plantation, except for the needle component. The C and N content of needles was significantly larger in the 13-year-old plantation than in the 41-year-old plantation, whereas fine woody materials, such as branches and bark, contributed less to the total C and N contents in the 13-year-old plantation. The total C content of the forest floor did not significantly differ with age, whereas the N content was significantly affected by age in the radiata plantations. The results reflect the existence of considerable variation in the quality and quantity of the C and N in forest floor components associated with different ages of radiata pine growing in sites of various qualities.