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Tian G.-H.,Agricultural University of Hebei | Wang D.-Q.,Forest Survey and Design Institute of Jilin Province | Gu J.-C.,Agricultural University of Hebei | Tan X.-Q.,Agricultural University of Hebei | Lu G.-Q.,Agricultural University of Hebei
Beijing Linye Daxue Xuebao/Journal of Beijing Forestry University

This study compared the spatial structures among different stand types in Saihanba Mechanized Forest Farm by using three indices, i.e. the neighborhood comparison, uniform angle index and mingling degree. The results show that there exists competition within the stands, which did not affect the growth of trees. In the sample plots, No.2, 3, 5, 7, the differentiation within stands was quite obvious, indicating that we should take some forest management and tending measures. The mean values of uniform angle index in nine sample plots ranged from 0.50 to 0.60, which showed an aggregation distribution pattern. In the mixed forests, the average mingling degree were low, suggesting a less-mixed degree. According to spatial structures and different management purposes of the stands, we can take reasonable measures for forest management. Source

Han M.-G.,Northeast Forestry University | Shi B.-K.,Northeast Forestry University | Shi B.-K.,Forest Survey and Design Institute of Jilin Province | Jin G.-Z.,Northeast Forestry University
Journal of Soils and Sediments

Purpose: There is a paucity of data regarding the multiple timescale variations of heterotrophic respiration (RH) and autotrophic respiration (RA) as well as the primary controlling factors. The objective of this study is to find the temporal variations of total soil respiration (RS) and its components, revealing the driving factors at different timescales. Materials and methods: A trenching method was used to distinguish RS, RH, and RA in a spruce-fir valley forest in northeastern China. We used the closed dynamic chamber method to measure the soil respiration rate. Analyses of RS, RH, and RA in relation to biotic and abiotic factors were conducted to realize the temporal variations at different timescales. Results and discussion: Only RS and RH showed a distinct diurnal variation and soil temperature (TS) can explain 68 and 59 % of the daily variation, respectively. RS, RH, and RA showed a pronounced, single peak curve seasonally, and TS can explain 11–95 % of the seasonal variation. Soil moisture (WS) maintained at a relatively high level and was not related to RS, RH, or RA on a seasonal scale, and there was no significant relationship between the seasonal RS, RA, and root biomass. However, for 5 years, only the mean RA of the growing season was significantly related to the mean WS, which can explain 39 % of the inter-annual variation of RA. The annual variations of litterfall and the relative growth rate of stems were not related to RS, RH, or RA. The contribution of RH to RS was larger, and the temperature sensitivity was 2.01–3.71 for RS, 1.90–3.08 for RH, and 2.20–5.65 for RA. Conclusions: RS, RH, and RA show different temporal variations at multiple timescales. When WS is not restricted, TS is the primary driving factor of daily and seasonal variation of RS and RH. In this site, RH accounts for a large proportion of RS and plays a crucial role in determining the magnitude and temporal variation of RS. © 2016 Springer-Verlag Berlin Heidelberg Source

Shi B.,Northeast Forestry University | Shi B.,Forest Survey and Design Institute of Jilin Province | Gao W.,Northeast Forestry University | Cai H.,Northeast Forestry University | Jin G.,Northeast Forestry University
Plant and Soil

Aims: The aim of this study was to quantify and understand the driving factors of the spatial variation of soil respiration (RS) in an old-growth mixed broadleaved-Korean pine forest in northeastern China. Methods: All woody stems ≥1 cm diameter at breast height (DBH) were measured in the 9 ha plot. Simultaneous measurements of RS, soil temperature (TS) and soil water content (WS) were conducted for 256 sampling points on a regular 20-m grid refined with 512 additional sampling points randomly placed within each of the 20-m blocks in May, July and September of 2014. Results: The variogram analyses revealed 87–91 % of the sample variance was explained by autocorrelation over a range of 15 to 23 m during the observation periods. The RS were highly correlated among the measurements made in May, July and September. The model indicated that the WS, bulk density (BD) and maximum DBH for trees within 3 m (radius) of the measurement collars explained 46 % of the spatial variation in RS seasonally averaged across three observations. Conclusions: The spatial patterns of RS remained constant across the three measurement campaigns. The spatial variation in RS was primarily controlled by the WS and forest stand structure. © 2015, Springer International Publishing Switzerland. Source

Shi B.,Northeast Forestry University | Shi B.,Forest Survey and Design Institute of Jilin Province | Jin G.,Northeast Forestry University
Biology and Fertility of Soils

To identify the controlling factors of the variability of soil respiration (RS) at multiple spatial scales, RS was measured along with environmental factors, tree diameter at breast height (DBH), and soil properties for four typical forest types in northeastern China, including the primary mixed broad-leaved Korean pine (Pinus koraiensis) forest (BKPF), spruce-fir valley forest (SVF), selective cutting of mixed broad-leaved Korean pine forest (SCF), and Korean pine plantation (KPP), throughout the growing season (May–October) in 2013. The variability of RS was quantified and compared at the following three spatial scales: among collars within a plot, among plots within a specific forest stand, and among forest stands within the landscape. The average coefficients of variations of RS within plots (30–52 %) were significantly higher than those of RS among plots (20–25 %) in each forest stand (P < 0.05). The water-filled pore space and mean DBH of trees within 8 m of the measurement collars explained 72 % of the variability of RS within the BKPF. The variabilities of RS within the SVF, SCF, and KPP were explained by the soil organic C content, soil C:N ratio, and mean DBH and total basal area of trees within a few meters of the measurement collars. The variability of RS across the four forest stands was best explained by the soil C:N ratio (R2 = 0.63, P = 0.001). © 2016, Springer-Verlag Berlin Heidelberg. Source

Shi B.,Northeast Forestry University | Shi B.,Forest Survey and Design Institute of Jilin Province | Gao W.,Northeast Forestry University | Jin G.,Northeast Forestry University
European Journal of Soil Biology

To evaluate the effects of forest transition (conversion of primary temperate forest into secondary forest and plantations) on rhizospheric (RR) and heterotrophic respiration (RH), we used the trenching-plot and infrared gas exchange analyzer approaches to partition soil respiration (RS) for four temperate forest types in northeast China, including the primary mixed broadleaved-Korean pine (Pinus koraiensis) forest, secondary birch (Betula platyphylla) forest, Dahurian larch (Larix gmelinii) plantation and Korean pine plantation, throughout the growing season (May-October) in 2011 and 2012. The results showed that RS and its components displayed obvious seasonal dynamics and were mainly controlled by soil temperature. Furthermore, incorporating soil moisture into the pure RS (RH)-temperature model improved the prediction of RS and RH in most forest types (RS, R2=0.687-0.799; RH, R2=0.721-0.849). The apparent temperature sensitivity (Q10) of RR (2.69-5.16) was higher than that of RH (2.34-2.56) in all forest types. The average RH was increased by 35% following the conversion of primary forest to secondary birch forest, 31% to larch plantation and 19% to pine plantation. Such increment of RH could be explained by the increase of soil organic carbon storage in the top soil. When the primary forest was converted to secondary birch forest, the average RR significantly increased (P<0.05), but no significant differences in RR between primary forest and two plantations were detected (P>0.05). The differences in RR between secondary birch forest and primary forest and two plantations may reflect differences in small root biomass (<5mm in diameter) at a depth of 0-40cm and with soil microbial biomass carbon in the top soil. Our results suggest that mechanisms controlling RH and RR are probably different and that partitioning soil respiration when evaluating the effect of forest conversion on soil respiration is important. © 2014 Elsevier Masson SAS. Source

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