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    抚育强度对不同林型“栽针保阔”红松林碳源/汇影响

    Effects of tending intensity on carbon source/sink of Korean pine forests with different forest types by planting coniferous forest and reserving broadleaved forest

    • 摘要:
        目的  揭示透光抚育对不同林型中期“栽针保阔”红松林碳源/汇影响规律,为恢复地带性顶极植被阔叶红松林提供依据。
        方法  运用静态箱−气相色谱分析及相对生长方程法,同步测定小兴安岭3种中期“栽针保阔”红松林(蒙古栎红松林、白桦红松林和山杨红松林冠下栽植红松25 ~ 35年及透光抚育25 ~ 30年)在不同透光抚育强度(对照、轻度透光抚育、强度透光抚育)下的土壤异养呼吸净碳排放量(CO2和CH4)、植被年净固碳量及相关环境因子(温度、土壤含水率、有机碳、全氮等),并依据生态系统净碳收支,确定林型和透光抚育强度对中期“栽针保阔”红松林碳源/汇的影响规律及其机制。
        结果  (1)3种林型土壤CO2年均通量(159.94 ~ 207.43 mg/(m2·h))既受透光抚育强度影响(强度透光抚育使蒙古栎红松林显著提高18.9%),也受林型影响(对照林分白桦红松林显著大于蒙古栎红松林和山杨红松林,轻、强度透光抚育下3种林型相近);各透光抚育强度对3者的土壤CH4年均通量(−0.047 ~ −0.028 mg/(m2·h))无显著影响,但白桦红松林和山杨红松林显著高于蒙古栎红松林;(2)轻、强度透光抚育对3种林型的植被年净固碳量(1.66 ~ 3.99 t/(hm2·a))无显著影响,但在各透光抚育强度下白桦红松林显著高于蒙古栎红松林和山杨红松林(105.4% ~ 124.1%和31.0% ~ 32.6%),山杨红松林又显著高于蒙古栎红松林(55.7% ~ 71.1%);(3)轻度透光抚育对蒙古栎红松林(−1.93 ~ −1.12 t/(hm2·a))、白桦红松林(−0.13 ~ 0.46 t/(hm2·a))和山杨红松林(−1.03 ~ −0.65 t/(hm2·a))碳汇已无显著影响,而强度透光抚育的影响程度和方向与林型密切相关(蒙古栎红松林源强显著提高72.3%,白桦红松林由碳汇转化为弱源,山杨红松林源强变大但差异性不显著)。
        结论  因此,从中期“栽针保阔”红松林维持森林碳汇方面考虑,对恢复较快的白桦红松林和山杨红松林可以采取强度透光抚育,而对恢复较慢的蒙古栎红松林则适宜采取轻度透光抚育。

       

      Abstract:
        Objective  This paper aims to reveal the influencing rule of forest type and light-felling intensity on the carbon source and sink of Korean pine forests by planting coniferous forest and reserving broadleaved forest (PCRBT), and to provide basis for the restoration of zonal climax vegetation broadleaved Korean pine forest.
        Method  The annual net carbon sequestration of vegetation, net carbon emission (CH4, CO2) of soil heterotrophic respiration with related environmental factors (temperature, water content of soil, organic carbon, total nitrogen, etc.) under different light-felling intensities (control, low-intensity, heavy-intensity) were measured simultaneously by static chamber-gas chromatograph and relative growth equation in three types of Korean pine forests by PCRB (Mongolian oak-Korean pine forest and white birch-Korean pine forest, and Korean pine was planted under secondary crown for 25−35 years and light-felling for 25−30 years) in temperate in Xiaoxing’an Mountains of northeastern China, in order to reveal the influence of forest type and light-felling intensity on the carbon source/sink of Korean pine forest according to the net carbon balance of ecosystem.
        Result  (1) The annual average efflux of soil CO2 (159.94−207.43 mg/(m2·h)) in three forest types was influenced by both the intensity of light-felling (heavy-intensity light-felling significantly increased by 18.9% from Mongolian oak-Korean pine forest), and the forest type (control was white birch-Korean pine forest, which was significantly higher than aspen-Korean pine forest and Mongolian oak-Korean pine forest, low and heavy light-felling had no significant impacts among three forest types); low and heavy light-felling had no significant impacts on the annual average flux of soil CH4 uptake (−0.047 − −0.028 mg/(m2·h)) from three forest types but white birch-Korean pine forest and aspen-Korean pine forest were significantly higher than Mongolian oak-Korean pine forest. (2) Low and heavy-intensity light-felling made the annual net carbon sequestration of vegetation (1.66−3.99 t/(ha·year)) from three forest types had no significant effect, but white birch-Korean pine forest was significantly higher (105.4%−124.1% and 31.0%−32.6%) than aspen-Korean pine forest and Mongolian oak-Korean pine forest , aspen-Korean pine forest was significantly higher(55.7%−71.1%) than Mongolian oak-Korean pine forest. (3) Low-intensity light-felling had no significant impacts on carbon sink in Mongolian oak-Korean pine forest (−1.93 − −1.12 t/(ha·year)) and aspen-Korean pine forest (−1.03 − −0.65 t/(ha·year)) and White birch-Korean pine forest (−0.13−0.46 t/(ha·year)), but the level and direction of the effect of heavy-intensity light-felling were closely related to the forest type, Mongolian oak-Korean pine forest had significantly increased by 72.3%, white birch-Korean pine forest converted into carbon source, aspen-Korean pine forest had slightly increased carbon source.
        Conclusion  Therefore, considering the maintenance of forest carbon sink in Korean pine forests by PCRBT, the faster recovering white birch-Korean pine forest and aspen-Korean pine forest is more appropriate to take heavy-intensity light-felling, while the slower recovering Mongolian oak-Korean pine forest is suitable to be low-intensity light-felling.

       

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