Koraiensis Plantation Research Articles

Effect of soil phenolic acids on soil microbe of coal-mining depressed land after afforestation restoration by different tree species

Phenolic acids are one of the most important factors that influence microbial community structure. Investigating the dynamic changes of phenolic acids and their relationship with the microbial community structure in plantation soils with different tree species could contribute to better understanding and revealing the mechanisms of microbial community changes under afforestation restoration in coal-mining subsidence areas. In this study, plantations of three conifer and one deciduous species (Pinus koraiensis, Larix gmelinii, Pinus sylvestris var. mongolica, and Populus ussuriensis) were established on abandoned coal-mining subsidence areas in Baoshan District, Shuangyashan City. The contents of soil phenols, 11 types of phenolic acids, and microbial communities in all plots were determined. The results showed that the contents of soil complex phenol in plantations were significantly higher than that of abandoned land overall. Specifically, soils in larch and poplar plantations had higher contents of complex phenol, while soils in larch and Korean pine plantations had greater contents of total phenol. Moreover, soil in the P. koraiensis plantation had a higher content of water-soluble phenol compared with abandoned lands. The determination of 11 phenolic acids indicated that the contents of ferulic acid, abietic acid, β-sitosterol, oleanolic acid, shikimic acid, linoleic acid, and stearic acid were higher in plantation soils. Although soil phenol contents were not related with soil microbial biomass, the individual phenolic acids showed a significant relationship with soil microbes. Ferulic acid, abietic acid, and β-sitosterol showed significant promoting effects on soil microbial biomass, and they showed positive correlations with fungi and fungi/bacteria ratio. These three phenolic acids had higher contents in the poplar plantation, suggesting that poplar affo-restation had a beneficial effect on soil quality in coal-mining subsidence areas.

6种温带森林凋落量年际及年内动态

PDF HTML阅读 XML下载 导出引用 引用提醒 6种温带森林凋落量年际及年内动态 DOI: 10.5846/stxb201509091861 作者: 作者单位: 东北林业大学生态研究中心,东北林业大学生态研究中心,东北林业大学生态研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 教育部长江学者和创新团队发展计划（IRT15R09）；中央高校基本科研业务费专项资金项目（2572014AA11） Inter- and intra-annual dynamics in litter production for six temperate forests Author: Affiliation: Center for Ecological Research,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University,Center for Ecological Research,Northeast Forestry University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:森林凋落物量及其组分因生态系统结构特征和环境变化而表现出明显的时间动态，从而影响森林生态系统物质循环和生态服务功能。连续6年观测帽儿山地区6种温带森林凋落物量及组份的时间动态、温度和降雨量等气象因子，旨在深入了解该地区森林生态系统的物质循环过程及调控因子。结果表明：6种森林的年落凋落量差异显著，平均值依次为：蒙古栎林（4.60 t/hm2） > 杂木林（4.21 t/hm2） > 硬阔叶林（4.03 t/hm2） > 红松林（3.95 t/hm2） > 杨桦林（3.89 t/hm2） > 落叶松林（3.85 t/hm2）。各森林年凋落量的年际变化表现为“升高-降低”交替波动模式，但总体上呈上升趋势。凋落物各组份的年际变化不同，枝凋落量变化较为稳定；叶凋落量与凋落总量一致，升高-降低波动明显；繁殖器官及其他凋落量随林龄增加而增加。各森林凋落物量的年内变化呈单峰曲线波动，最大值出现时间因林型而异。枝凋落量在年内表现为双峰曲线模式波动；叶凋落量年内呈单峰曲线模式波动，并与凋落总量年内动态一致；繁殖器官与其他凋落量年内动态波动平缓，无明显凋落峰值。降雨量显著影响年凋落物量（P < 0.05），分别解释了凋落总量、叶凋落量90%、87%变化。平均温度、积温和总降雨量显著影响凋落量年内动态，总降雨量的影响作用最为突出。因此，除林分自身的生物学特性外，降雨是影响该温带森林凋落量年内、年际动态的重要因素。 Abstract:Litter production and its composition in temperate forests show seasonal dynamics due to changes in the ecosystem structure and environment, which directly affect the nutrient cycling and ecological services in the ecosystems. In this study, we investigated seasonal dynamics in the litter production and its composition for six forest types in Maoershan region for six continuous years in order to reveal the factors driving the inter- and intra-annual variability of the litter production. The results showed that annual litterfall (t/hm2) decreased in the order of:Quercus mongolica stand (4.60) > mixed deciduous stand (4.21) > hardwood stand (4.03) > Pinus koraiensis plantation (3.95) > Populus-Betula stand (3.89) > Larix gmelinii plantation (3.85). There was a significant difference in total litterfall among the six stands. The litter production fluctuated interannually and showed an overall increasing tendency. The interannual variation in the litter composition depended upon its compoents:the litter production of woody tissues was relatively stable; that of foliages was consistent with the total litter production; and that of reproductive tissues and others increased with stand age. The production of total litter showed a mono-peak seasonal pattern for all the stands, and the occurrence of the peak varied with forest type. The litter production of woody tissues displayed a bimodal seasonal course; that of foliages was a mono-peak curve; and that of reproductive tissues and others was relatively stable intra-annually. Total rainfall significantly influenced the inter-annual litter production (P < 0.05), and explained 90% and 87% of the variability in the total litter production and the production of woody tissues, respectively. Mean temperature, cumulative temperature and total rainfall significantly affected intra-annual variability in litter production, among which the effect of total rainfall was dominant. In conclusion, rainfall, in addition to the biological characteristics of the forests, was a key factor driving the inter- and intra-annual dynamics in litter productions. 参考文献 相似文献 引证文献

帽儿山红松人工林鞘翅目成虫群落小尺度空间异质性变化特征

帽儿山红松人工林鞘翅目成虫群落小尺度空间异质性变化特征

A Study on Annual Carbon Emission Characteristic Changes Affected by Rainfall

For better understand of the soil respiration characteristic in ecosystem, it is necessary to accurately determine the daily, monthly and seasonal CO₂ flux related to various environmental factors. In general, soil respiration is being measured on a sunny day. But soil respiration is known to be affected by soil temperature and soil moisture content. In case of forestry, changes in soil moisture content are entirely dependent on rainfall. If we calculated the monthly soil respiration measured based on sunny days data only, it could be a factor that loses credibility soil respiration. On this study, we measured soil respiration on Pinus koraiensis plantation at Mt. Taehwa of Gwangju, Gyeonggi-do on sunny and rainy days in 2012, using Automatic Open-Closed Chamber system (AOCC) and portable CO₂ analyzer (GMP343). Then we computed the regression equations using sunny days data, precipitation less than 10 mm data, and precipitation over 10 mm data. At first, there were no significant differences in observed data and computed data. But less than 10 mm precipitation, computed data was 26.5% lower than observed data. Precipitation over 10 mm, on the other hand, the former was 29.3% higher than the latter. In each case, it showed significant differences between observed and computed data (p0.05). So if we computed regression equation using soil respiration measured sunny days only, about 30% of annual soil respiration could be overestimated. Through further study, we suggest the subdivision and computation of regression equation on the basis of the rainfall intensity.

Carbon Density and Its Distribution of Pinus koraiensis Plantations in Different Regions of Heilongjiang Province

We explored the importance of forest carbon density and its distribution pattern for forest and global carbon cycling. By using the forest inventory and allometric approaches,we measured carbon density and its distribution characteristics of young growth Pinus koraiensis plantations in different regions of Heilongjiang Province including southern slope of Xiaoxing 'an Mountains,eastern slope of Zhangguangcai Mountains,western slope of Zhangguangcai Mountains,and Wanda Mountain). Among different regions,vegetation C pool and detritus C pool of P. koraiensis plantations varied significantly,but there was no significant differences in soil C pool and total C density. Vegetation,detritus,soil and total ecosystem C density were 35. 95- 76. 36,3. 52- 11. 34,101. 96- 173. 37 and 154. 54- 256. 78 tC·hm- 2,respectively. The distribution proportion of each ecosystem components were 18. 78%- 30. 34%,1. 79%- 5. 24% and 65. 58%- 79. 43%,respectively,and all differed significantly among regions. Overstory organs( except leaf) C density and its distributions were different significantly among regions. The C density of stem,branch,leaf and root were22. 47- 47. 11,2. 30- 12. 31,2. 90- 5. 80 and 7. 02- 17. 16 tC·hm- 2,respectively. And the corresponding distribution proportion were 51. 98%- 64. 80%,6. 68%- 17. 19%,6. 55%- 8. 34% and 20. 23%- 22. 55%,respectively. Root-shoot ratio(R /S) and ratio of soil C density(include detritus C density) to vegetation C density(SC /VC) were 0. 26- 0. 29 and 2. 31- 4. 69,respectively,with significant difference among regions.Basal area exhibited highly significant positive correlation with overstory C density,vegetation C density and forest ecosystem total C density(P 0. 01),which can well reflect the dynamic of forest ecosystem C density.

Modelling primary branch growth based on a multilevel nonlinear mixed‑effects model: a Pinus koraiensis plantation case study in north‑east China

On the basis of a multilevel nonlinear mixed‑effects model approach, branch diameter and length growth models were developed for a Pinus koraiensis plantation in north‑east China. The models developed were able to better capture the residual variation successfully by partitioning the residual variance into plot‑, tree‑ and branch‑ level variations via random parameter modeling at the three levels. In addition to random effects, various time series correlation structures were evaluated to account for residual autocorrelation, and the AR(1) and ARMA(1,1) structures were selected for the branch diameter and length growth models, respectively. Model validation results using an independent data set confirmed that multilevel mixed models with an appropriate correlation structure produced more accurate and precise branch‑specified diameter and length predictions. Overall, the models were suitable in describing the trends and inherent variability of crown profile and good enough to be included in growth simulation systems for Pinus koraiensis plantations.

Prediction Model of Nut Yields for Korean Pine Plantation

Logistic and non-linear models were developed for predicting nut yields for Korean pine( Pinus koraiensis) plantation based on 579 Korean pines measured in 12 sample plots in Mengjiagang forest farm, Jiamusi,Heilongjiang Province. First,the statistical analysis system( SAS 9. 22) was employed using data of pine nut yields to establish Logistic model for predicting whether individual pine could seed or not. Second,a non-linear regression was set up for predicting nut yields of individual seeded pines using tree variables. The results showed that the predicting accuracy of whether individual pine could seed or not,was above 65% for Logistic model. The optimal model of predicting nut yields was y = a( D2CW)bdue to the best fitting performance,which included the prediction accuracy of 77% and evenly distributed model residuals. The accuracy assessment was 92. 78% for the two models using the observed pine nut yield data of Plot 2,which indicated a good prediction performance. This paper has been provided suitable method for predicting pine nut yields for Korean pine plantation.

강원 중ㆍ북부 지역의 잣나무 임분구조 및 생장특성

The purpose of this research was to figure out the stand structure and growth characteristic with relation to DBH, height, and volume in sixteen Pinus koraiensis plantations of Gangwon province region. Age class was diversely distributed from age class II (16 yr) to age class VIII (77 yr), and, in terms of site index, sixteen regions were superior: nine regions 'high', seven regions 'middle'. The distribution of DBH by sites appeared a bell-shaped curve, and the number of trees was the most in diameter section of 18-22 cm. The dispersion of DBH was various with age and widest ranging from 18 cm to 58 cm in age class VII-VIII. The distribution of height was also a bell-shaped curve with the smaller deviation than the distribution of DBH, and most of trees were in height section of 14-18 m. The correlation of DBH and height was high (r=0.75), and the volume bigger than 1.0 <TEX>$m^3$</TEX> was presented from DBH 35 cm, height 20 m.

The effect of forest-thinning works on tree growth and forest environment

This research was conducted to provide effective forest management through forest tree production and forest land changes which took place after the forest-tending works in the plantation of Pinus koraiensis. It has been shown that the current annual diameter growth of trees in regions which implemented forest-tending projects in 2005 had increased by 142.9% compared to those which did not implement the forest-tending projects. In 2006, the current annual diameter growth of trees in implemented regions increased by 132.6% compared to those which did not implement forest-tending. Additionally, in the Pinus koraiensis plantation of Ⅲ·Ⅳ age classes where forest-tending projects works were implemented, the growth in diameter started to show a clear increase in the year following the implementation, and the maximum effects were displayed within 3–5 years. Thereafter, the growth gradually started to slow down. Therefore, implementing forest-tending works repetitively with a minimum period of 5 years would be considered appropriate. Soil moisture during the rainy season did not show significant differences as the soil moisture content remained at 40.4–43.0%. However, during the dry season, regions which did not implement forest-tending showed an average of 20.4%, and regions which implemented forest-tending showed an average of 26.6%, and the differences were greater when compared to the rainy season. Due to the control in the density of the number of forest trees due to forest-tending and forest thinning works, the number of understory woody plant species increased from 17 to 30 and the number of herbaceous plant species increased from 20to 44. Furthermore, as the density of standing trees was reduced to about 50% in places where forest-tending works were implemented, crown length ratios increased greatly from 46.1% to 62.1% and became a great help to the growth of forest trees.

Rain Fall Partition of the Forest Canopy beside Songhua River

Through field investigation and room experiment, the characteristics of the rainfall partition in the canopy layer of six forest types beside Songhua River were studied. The canopy interception of the rainfall was different in six forest types; from maximum to minimum was Quercus monglica forest, Pinus koraiensis plantation, Tilia mandshurica forest, Fraxinus mandshurica-Larix olgensis forest, Fraxinus mandshurica-Populus davidiana forest and Juglans mandshurica forest. There were significant linear correlation between through fall and precipitation and significant exponential correlation between canopy interception and precipitation in studied forest types; The stem flow ratio to gross rain fall ranged from 0.74% to 16.61% in six forest types, from maximum to minimum was Juglans mandshurica forest, Quercus monglica forest, Pinus koraiensis plantation, Fraxinus mandshurica-Larix olgensis forest, Fraxinus mandshurica-Populus davidiana forest and Tilia mandshurica Forest. In the same precipitation condition, the stem flow ratio to gross rain fall should be affected negatively by canopy size.

The Spatial Heterogeneity of the Soil Bulk Density under Different Management Types of &lt;i&gt;Pinus koraiensis&lt;/i&gt; Forests

Through the manner of field investigation and room experiments, by using software SPSS 13.0, software ArcGis 9.3 and geostatistical analysis tool, the spatial heterogeneity of the soil bulk density under virgin Pinus koraiensis forest, Betula platyphylla and Pinus koraiensis mixed forest (Pinus koraiensis natural regeneration), Betulaplatyphylla and Pinus koraiensis mixed forest (Pinus koraiensis planted) and pure Pinus koraiensis plantation were studied. The characteristics of the spatial heterogeneity of the soil bulk density under different forest types were different, the spatial heterogeneity of the soil bulk density under four forest types were influenced by random factors, but the auto relationship part of the soil bulk density spatial heterogeneity under Betula platyphylla and Pinus koraiensis mixed forests were bigger, and the change distance was smaller than that under pure Pinus koraiensis plantation. The spatial distribution pattern of the soil bulk density under Betula platyphylla and Pinus koraiensis mixed forests was superior to that under pure Pinus koraiensis plantation. The results would provide a theory basis for the recovery and the sustainable management of the Pinus koraiensis forest.

Biomass and nutrient concentrations of fine roots in a Korean pine plantation and a sawtooth oak stand

Fine root (<2 mm in diameter) biomass and nutrient concentrations were examined by a sequential core method at a soil depth of the top 15 cm in a Korean pine (Pinus koraiensis) plantation and a sawtooth oak (Quercus acutissima) stand in the Forest Practice Research Center, Gyeonggi-do, Korea. Live and dead fine root biomass showed a seasonal variation in pine and oak stands. Live fine root biomass generally decreased in the late growing season (September–November) with a seasonal peak in the early growing season (April–June), while dead fine root biomass in both stands showed high values in summer (July or August). Mean fine root (live, dead, total) biomass (g m−2) during the study period was higher for the Korean pine (142, 266, 408) than for the sawtooth oak stands (124, 193, 317). Nitrogen and phosphorus concentrations of live fine roots were little changed during the growing season, while other nutrient concentrations showed seasonal fluctuations during the study period. Nutrient concentrations were generally higher in the Korean pine than in the sawtooth roots except for calcium and phosphorus concentrations. The results indicate that fine roots could be attributed to below-ground nutrient cycling by the difference of biomass and nutrient concentrations induced from each stand type.

The Dynamic Process of the Soil Water under Six Forest Types beside Songhua River

The soil saturated water content, soil water permeability and the soil water content dynamic process under six forest types (Pinus koraiensis plantation, Fraxinus mandshurica-Populus davidiana forest, Fraxinus mandshurica- Larix olgensis forest, Tilia mandshurica forest Quercus monglica forest and Juglans mandshurica forest) beside Songhua River were measured in the sample forests and experiment room during May to September 2006. The soil saturated water contents under six forest types were from 2693.50 t/hm2 to 3184.31 t/hm2, the biggest value occurred under Fraxinus mandshurica-Populus davidiana forest, and the smallest value occurred under Quercus monglica forest. The initial permeability coefficient and stable permeability coefficient of the various soil layers under six forest types were bigger than that of bare land, and the biggest value occurred under Tilia mandshurica forest. The soil water content under six forest types had the same change tendency during growth season that was, high-low-high-low in May-June-July and August-September. The results would provide the theories basis for the forest management beside Songhua River.

Effects of Management Measures on Soil Properties of &lt;i&gt;Pinus koraiensis&lt;/i&gt; Plantations

The effects of four management measures (A: All broad-leaved trees and shrubs were cut, B: All broad-leaved trees were cut, C: All shrubs were cut, D: Partial upper broad-leaved trees were cut uniform.) of Pinus koraiensis plantations on the soil properties were studied in National Natural Reserve located in Lesser Xingan Mountains. Litter mass, soil organic matter mass, soil physical properties, soil chemical properties and microbial characteristics were affected significantly by management activities in the Pinus koraiensis plantations no matter what kind of management measures. The rate of undecomposed layer was bigger than 50% in measure A and measure B, and smaller than 50% in measure C and measure D. The lowest surface soil bulk density was in measure C and D. Soil organic matter mass of measure C and D was bigger than that of measure A and B. In the upper soil layer, the nutrient of measure C and D was higher than that of measure A and B. The totoal number of bacterium, fungi and actinomycetes was the bigger in measure C and D, and the smaller in measure A and B. The rusults of the soil properties under different management measures seems to confirm that increasing the degree of close-to-nature forest management could be conductive to improve the soil quality of Pinus koraiensis plantation.

잣나무림조림지에서 간벌이 절지동물 풍부도와 군집구조에 미치는 영향

Thinning treatment has a huge effect on understory and litter structures in forest ecosystem, and the resulting changes may impact some arthropod groups such as plant-feeders and detritivores. This study was carried out to find a change in arthropod abundance and their structures in relation to the thinning activity in a Pinus koraiensis plantation in Chuncheon, Korea, where thinning was conducted twice: in 1998-2000 (old-thinning) and 2007 (new-thinning). Arthropods were collected using pitfall traps in 2006 and 2008. Effects of old-thinning on change of abundance and community structure of arthropod were significant, but the effects of new-thinning were not significant. The most significant thinning effect was found in detritivores, followed by plant feeders, but the effect was hardly significant in predators. Among detritivores the changes in abundance was diverse. The abundance of orthopteran plant-feeder increased, but Curculionidae declined after thinning. There was not different in abundance of total arthropods between thinned and unthinned areas because the difference may have cancelled each other out by increased or decreased abundance of taxa. Community structures of arthropods were most greatly affected by years, followed by the old-thinning, but the new-thinning did not affect community structures.

Carbon pool structure and carbon density of soil in Pinus koraiensis plantation ecosystem

The organic carbon contents, carbon density and carbon storage of the soil in the Pinus koraiensis plantation ecosystem were investigated in Maoershan experimental forest farm, Shangzhi County, Heilongjiang, on the west slope of the Zhangguangcai Mountains in northeastern China for providing data to evaluation of the carbon balance in forest ecosystem of northeastern China. These soil carbon indicators were measured in three forest types, pure P. koraiensis plantation, P. koraiensis and Betula platyphylla mixed forest, and the P. koraiensis and Quercus mongolica mixed forest. The soil carbon pool consisted of four compartments, namely L layer, F layer, H layer and B layer. With variance analysis, we found that both organic carbon content and carbon density of the soil were significantly affected by forest types, soil compartments and slope positions. The highest soil carbon density (278.63 Mg·ha−1).was observed in the mixed forest of P. koraiensis and Q. mongolica. The B layer had the highest carbon density (212.28 Mg·ha−1) among all the soil compartments. In terms of slope position, the highest soil carbon density (394.18 Mg·ha−1) presented in the low slope. Besides, soil carbon content and carbon density had a marked change with the organic matter content and vertical depth of the soil in each compartment. The results of this study implied that in the temperate humid region, the mixed ecosystem of regional Pinus koraiensis plantations and natural forest had relatively high carbon storage capability.

Soil structure characters of different soil and water conservation plantations in typical black soil region

A study was conducted to determine the characters of soil structure in different water and soil conservation forests in Keshan County, northwest of Heilongjiang Province, China. The soil bulk density, the ratio of non-capillary porosity and capillary porosity (NCP/CP), and the generalized soil structure index (GSSI) were measured for Fraxinus mandshurica, Larix gmelini, Pinus sylvestris var. mongolica, and Picea koraiensis plantations as well as the abandoned land (as control) adjacent to the forests in typical black soil region. Results show that at soil depth of 0–30cm, the soil bulk density of F. mandshurica forest and L. gmelini forest was lower than that of P. sylvestris var. mongolica forest and P. koraiensis forest, with the relative decrease of 8.04%–11.01%. The soil bulk density of L. gmelini forest was significantly different from that of the P. sylvestris var. mongolica forest and P. koraiensis forest. The NCP/CP values of the four types of plantations were all higher (59.75%–128.82% relatively) than that of abandoned land (p<0.05), indicating that the soil aeration and permeability under forest were enhanced, especially under L. gmelini forest. GSSI values of the four types of forests were also relatively higher (2.98%–4.36%) than abandoned land (p<0.05), indicating that those soil and water conservation forests, especially the F. mandshurica forest and P. koraiensis forest, can promote soil condition to approximate ideal soil structure. The result of this study can provide theoretical basis for scientifically evaluating the effects of vegetation restoration on soil quality in typical black soil region.

The Chemical Properties of Water in &lt;i&gt;Pinus&lt;/i&gt;&lt;i&gt; koraiensis&lt;/i&gt; Plantation at Mountainous Region in Heilongjiang Province

In this paper, the Pinus koraiensis plantation at mountainous region in Heilongjiang Province is the research object. Four different types of water in Pinus koraiensis plantation including rainfall, throughfall, stemflow and runoff are respectively selected to study the influence of Pinus koraiensis plantation on the water quality from May to November of 2004. The indicator included pH, Do, TURB, TDS, COND, ORP, K, Na, Ca, Mg, Cu, Zn, Mn and Fe. The results show that the chemical properties of rainfall have been changed after it passing through forest canopy. The value of pH, Do and ORP in throughfall are lower than those of rainfall, the value of TURB and TDS increase obviously, 3.2 and 6.4 times higher than the rainfall. The concentrations of Na, Ca and Zn in the throughfall are lower than those in the rainfall but other metal elements show higher concentrations. The value of pH and Do in stemflow are lower than other water. The element contents in stemflow increase greatly except Cu. The values of pH, TURB, TDS and COND in the runoff are higher than those in stemflow, throughfall and rainfall. The variance of pH and Do don’t change significantly, and the variance coefficients of pH and Do are lower in rainfall, throughfall, stemflow and runoff. The value of TURB, TDS and COND vary remarkably, and the variance coefficients of which are higher. The leaching coefficient of throughfall is in the following order: K&gt;Mg&gt;Mn&gt;Fe&gt;Cu&gt;Na&gt;Zn&gt;Ca. The leaching coefficient of stemflow is in the order of Fe&gt;Mn&gt;Mg&gt;K&gt;Na&gt;Ca&gt;Cu&gt;Zn. After atmospheric precipitation passing through the Pinus koraiensis plantation, the value of pH in the throughfall, stemflow and runoff increase gradually closer to neutral, which shows that the Pinus koraiensis plantation have good buffer function to the acidification of the water.

The Effects of Thinning on Fine Root Distribution and Litterfall in a Pinus koraiensis Plantation

The purpose of this study was to investigate the effects of thinning on fine root biomass and vertical distribution. and litterfall amount in a 50 year old Pinus koraiensis plantation in Chuncheon, Kangwon Province. Fine root (< 2 mm in diameter) biomass (<TEX>$367\;g/m^2$</TEX>) in the site 'OC_75', thinning once in 1975, was 68% of those in the site 'CON', no thinning after planting, and in the site 'TC_00', thinning twice in 1975 and 2000. There were no significant differences of dead roots among treatments. Diameter <TEX>$0{\sim}1\;mm$</TEX> roots were vertically decreased only in the TC_00 site. The litterfall was very similar between OC_75 (<TEX>$5.2\;Mg\;ha^{-1}\;yr^{-1}$</TEX>) and TC_00 (<TEX>$4.7\;Mg\;ha^{-1}\;yr^{-1}$</TEX>), but the composition of litterfall was different: The proportion of leaves and branches was 80% and 13% in OC_75 and 56% and 36% in TC_00, respectively. Reduction of P. koraiensis density by thinning decreased leaf litter as well as fine roots of P. koraiensis, but increased fine roots production by neighboring understory plants offset the reduction of fine roots of P. koraiensis. We suggest that belowground as well as aboveground responses, including both over- and understory vegetation, should be considered to measure the responses of trees in thinned forest ecosystems.

Soil organic carbon, nitrogen and microbial properties in contrasting forest ecosystems of north-east China under different regeneration scenarios

We compared soil organic carbon (SOC), nitrogen (N), and microbial populations and biomass in a natural Pinus koraiensis forest, a secondary (regenerated) forest, and P. koraiensis and Larix gmelinii plantations in Liangshui Nature Reserve, north-east China. Surface SOC, total N and microbial populations and biomass from the P. koraiensis plantation were significantly lower compared to natural and regenerated forests. Although surface SOC from the L. gmelinii plantation was not significantly different from either the natural and secondary forests, surface soil microbial populations and biomass from the L. gmelinii plantation were significantly lower. Differences among sites became less pronounced in subsoils (10–20 and 20–30 cm). There were positive and significant correlations between SOC, total N and microbial populations and biomass. The study showed that the tested soil characteristics, both abiotic and biological, from a naturally regenerated forest were more similar to those of an intact, natural forest, than either of the plantations. The P. koraiensis plantation demonstrated more impacts (e.g., lower microbial densities and reduced SOC) than the L. gmelinii plantation. Soil microbial properties appeared to be more sensitive than SOC or total N as indicators of damage to the soil microcosm.