Kwang-Soo Lee

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.

Effects of Fertilizer on Growth, Carbon and Nitrogen Responses of Foliage in a Red Pine Stand

This study was to examine growth, carbon and nitrogen responses in foliage following forest fertilization in a red pine stand. Two types of fertilizer (N:P:K=113:150:37 kg ha -1 ; P:K=150:37 kg ha -1 ) were applied on late April 2011. Growth, carbon and nitrogen responses of foliage were monitored 3 times (July, September, November) after fertilization. Morphological growth responses (dry mass, leaf area, specific leaf area) with foliage age were not significantly (P > 0.05) affected by fertilizer application, while needle dry mass and leaf area of July were significantly lower in current-year-old than in one-year-old or two-year-old needles of September or November. Carbon concentration and content in foliage was little affected by fertilizer application compared with sampling month or needle age, while the NPK fertilizer produced high nitrogen concentration and content of foliage. The results indicate that nitrogen concentration and content in foliage may serve as an indicator of the nitrogen status by fertilization in a red pine stand.

Biomass conversion factors for tree species and verification of applicability for national factors in Korea

Biomass conversion factors such as stem densities and biomass expansion factors of eight tree species and their applicability as national factors were determined. The stem densities of Cryptomeria japonica (III), Chamaecyparis obtuse (III), Pinus densiflora (IV), Pinus rigida (IV), Pinus koraiensis (IV), Larix leptolepis (IV), Quercus acutissima (III), and Liriodendron tulipifera (IV) were 0.37, 0.33, 0.46, 0.41, 0.58, 0.65, 0.88, and 0.58 g/ cm3, respectively. The biomass expansion factors of C. japonica (III), C. obtuse (III), P. densiflora (IV), P. rigida (IV), P. koraiensis (IV), and L. leptolepis (IV) were 1.393, 1.360, 1.150, 1.136, 1.212, and 1.097 (aboveground), respectively. Q. acutissima (III) had biomass expansion factors of 1.133 (aboveground) and 1.185 (underground), and L. tulipifera (IV) had biomass expansion factors of 1.161 (aboveground) and 1.216 (underground). As a result of verifying applicability as national factors using the investigated factors, it could be assumed that the stem density (0.47 g/ cm3) and biomass expansion factor (1.29 aboveground) in coniferous trees and the stem density (0.65 g/ cm3) and biomass expansion factor (1.22 aboveground) in hardwood trees were suitable for determining biomass. Based on these results, precise estimation of forest biomass classified by forest type, tree species, and age classes of Jeonbuk region would be possible.

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.