Effects of close-to-natural thinning on ground vegetation and tree regeneration of Quercus wutaishanica forest | 近自然经营间伐对辽东栎林植物组成及林木更新的影响

Chinese. 研究不同间伐强度下辽东栎林的植物组成及林木更新状况，为辽东栎林间伐经营与伐后管理提供依据。2004年对黄土高原黄龙山林区辽东栎林固定样地进行近自然经营间伐，采用间伐材积强度为13.4%（弱度）间伐后天然更新和间伐材积强度为30.0%（强度）间伐后人工补植油松2种经营措施,以未间伐为对照，研究伐后第1年（2005年）和第6年（2010年）林地乔灌草植物组成、单一物种盖度和林木更新状况。①间伐后第6年，除乔木层盖度外，弱度与强度间伐样地乔灌草层的物种数、高度和盖度均高于对照样地，其中乔灌草的物种数及乔木层和草本层高度与对照均无显著差异，而灌木层高度及乔灌草层盖度与对照均有显著差异。②与伐后第1年相比，伐后第6年的林地单一物种盖度发生了改变。③间伐措施使林下乔木幼苗幼树密度增加，尤其是辽东栎、油松、茶条槭和山杨，其幼苗幼树密度均随着间伐强度的增加而增大。④调查期间，辽东栎更新没有困难,但近自然间伐后，显著提高了其幼苗幼树密度。⑤间伐后第6年，油松天然更新幼苗幼树数量匮乏，且间伐措施不能显著提高其幼苗幼树密度，而人工补植油松是促进幼苗幼树更新的有效手段。在黄土高原黄龙山林区，近自然经营间伐措施能够促进辽东栎次生林的植物合理组成以及林木更新，是一种有效的森林经营方式。积极的经营策略，如间伐、人工种植幼苗等，能增加目的树种的数量，促进森林朝着健康的演替方向发展。近自然经营进行间伐材积强度为30.0%间伐后人工补植油松,更适合当地辽东栎次生林的抚育管理。

English. In this paper, the effects of close-to-natural thinning on ground vegetation and tree regeneration of Quercus wutaishanica forest were studied. This would provide reference for cutting operation and management after felling. We conducted investigation on plots of Q. wutaishanica forest after thinning with different silvicultural treatments in Huanglongshan region on the Loess Plateau in 2004. Compared with the uncut treatment, managements were close-to-natural forest management thinning 13.4% (light thinning) and self-regenerating forests thinning 30.0% (heavy thinning) and planting of Pinus tabulaefomis. The vegetation changes and tree regeneration were observed following the first (2005) and sixth (2010) growing seasons after thinning. ① Growth factors were different under different thinning levels after 6 years’ of thinning. There were no significant differences in species number of tree, shrub and herb. The growth height of tree and herb showed no significant difference whereas the shrub did. The coverage of tree, shrub and herb showed significant difference. ② Compared with the first year, the cover values of single vegetation had changed after 6 years’ thinning. ③ The individual number of the seedling in thinning plots was increased, such as, e.g., Q. wutaishanica, P. tabulaefomis, Acer ginnala and Populus davidiana, whose seedling increased with intensity thinning. ④ Q. wutaishanica saplings successfully regenerated during the observation period. But the close-to-natural plantation thinning was the key to speed up regeneration development. ⑤ Few natural seedlings of P. tabulaefomis was found in un-thinning and thinning plots, which proved that this species wasn’t able to establish spontaneously. Artificial planting P. tabulaefomis seedling after heavy thinning was an effective management to make up for lack of seedling. The close-to-natural forest management was more advantageous to ground vegetation and tree regeneration of Q. wutaishanica forest. This can be integrated into silviculture as positive forest conversion management in Huanglong forest region on the Loess Plateau. An active treatment like thinning of stands, or planting of trees, can accelerate forest conversion with regard to number of trees species. Close-to-natural plantation thinning 30.0% (including planting of Pinus tabulaefomis) was more suitable for the management of Q. wutaishanica secondary forest.