作 者 ：李国雷,刘勇*,于海群,吕瑞恒,李瑞生
期 刊 ：生态学报 2009年 29卷 3期 页码：1264~1275
关键词：油松人工林；生长规律；林下植被；物种多样性；生物量；
Keywords:Pinus tabulaeformis plantation, growth rhythm, undergrowth, species diversity, biomass,
摘 要 ：林下植被作为森林生态系统的一个重要组成部分，对维持林分结构和土壤质量起着重要作用。不同年龄树种对林下植被发育的影响已有所涉及，但这些为数不多的研究往往割裂了林木种群的生长规律与其林下植被间的相互作用，以林龄为尺度探讨林下植被发育的差异必然掩盖了林分种群对林下植被作用的异质性。采用时序研究法，按照油松(Pinus tabulaeformis)高速生期、径速生期、材积慢生期和材积速生期等不同发育时期，探讨林下植被组成、多样性、生物量和元素积累量的差异性。结果表明，高速生期阶段油松与林下植被竞争最为激烈，林下植被物种丰富度、多样性、生物量、元素积累量均最低。因此，高速生期阶段应及时对油松采取较大强度的抚育间伐以缓和油松种群与林下植被剧烈竞争的关系。径速生阶段林下植被与油松竞争最为缓和，草本层Gleason、Shannon-Wiener、Pielow指数由高生长阶段的7.817、2.222和0.769剧增到19.978、3.470和0.907，灌木层、草本层地上部分生物量、元素积累量也均达到最大。径速生阶段对油松林分的管理可相对粗放一些。进入材积阶段，油松与林下植被的关系日趋紧张。材积慢生阶段灌木层、草本层生物量由径速生期的2 262.61、461.92 kg/hm2分别下降至1 54985、 220.84 kg/hm2，而灌木层Gleason、Shannon-Wiener指数均达到峰值。相对于材积慢生期，材积速生期灌木层、草本层物种多样性指数、元素积累量进一步下降，而生物量略有上升，材积速生期阶段应对油松林分适度间伐或主伐。可见，林下植被可作为人工纯林乔木生长规律的指示剂，根据林下植被发育状况选择林分经营方式具有一定的参考价值。
Abstract:Undergrowth, one important component of the forest ecosystem, plays an important role in maintaining the forest structure and soil quality. The effect of forest at different age on undergrowth has been well documented in a few previous studies. However, those studies, thosen aregarding forest age as time scale tended to neglect the interactions between tree population growth and its undergrowth, thus overlapping inevitably the heterogeneous response of the undergrowth to tree population itself. In this paper, we investigated plant composition, diversity, biomass and nutrient accumulation in the undergrowth of Pinus tabulaeformis forest using a time scale of development rhythm: the height rapid growth, diameter rapid growth, volume slow growth and volume rapid growth. Results showed that it was at the height rapid growth stage when the competition between Pinus tabulaeformis and its undergrowth was severest and abundance, diversity, biomass and nutrient accumulation in the undergrowth were lowest. Therefore, severe thinning should be proposed to be adopted at this stage to relieve the strong competition between them. The slightest competition between Pinus tabulaeformis and its undergrowth occurred at the diameter rapid growth stage, when the aboveground biomass and nutrient accumulation of both the shrub and herb layers reached the maximum and the Gleason, Shannon-wiener and Pielow indices of herb layer have increased from 7817, 2.222 and 0.769 at the height rapid growth stage to 19.978, 3.470 and 0.907 at the diameter rapid growth stage, respectively. Accordingly, forest can be relatively extensively cultivated during this stage. When entered the volume stages, the competition between Pinus tabulaeformis and its undergrowth became daily intensive. The biomass of shrub and herb layer decreased from 2 262.61kg/hm2 and 461.92 kg/hm2 at the former stage to 1 549.85 kg/hm2and 220.84 kg/hm2 at the volume slow growth stage, respectively. While the Gleason and Shannon-wiener indices of the shrub layer increased to the maximum at the stage. Compared with volume slow growth, the diversity indices and nutrient accumulation of both shrub and herb layers were lower at the volume rapid growth stage. While the aboveground biomass in the shrub and herb layers was slightly enhanced further. Moderate thinning or cutting should be taken at the volume rapid growth stage. These results indicated that the development of undergrowth could be regarded as an indicator as growth rhythm of the arbor of pure plantations. And It is of reference values to select forest management ways according to the development of undergrowth.
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