海南岛陆均松天然更新障碍机制研究

Forest regeneration is an important ecological process, decide deveoplment directation of forest, produce important role and effect to change and benefects of ecologic, economic and social of forest. It may lead to reducing of natural regeneration effect if natural regeneration barriers are not seriously. It may lead tree ectinct if natural regeneration barriers are seriously. Dacrydium pierrei de Laubenfels belong to Dacrydium Solander ex G．Forster of Podocarpaceae, it is a good tree for timber, environment protection and garden green, only distributed in Hainan Island, one of symbol trees of tropical mountain rain forest in Hainan Island. It was third protection plant in 《Red book on Protection of Rare and Endangered Plants in China》.According to investigation in 1995 year, big tree are more, seedling and young tree is serious lack in Dacrydium pierrei de Laubenfels natural forest in Hainan, indicate it's natural regeneration produced serious barriers. This project will adopt contrast experiment way with present stand investigation and artificial regeneration under canopy and gap of forest, research character of seed, seed rain, soil seed bank, seedling and young tree of Acrydium pierrei de Laubenfels, delineate menchanism of natural regeneration barriers of Acrydium pierrei de Laubenfels from bio-control, environment factors change, disturb of person and nature. Provide support of theory, means and technology to diagnosis of natural regeneration barriers, and protection, restoration, development of Acrydium pierrei de Laubenfels forest

森林更新是一个重要的生态过程，决定森林群落的发展方向，对森林的演变和生态、经济和社会效益产生重要影响。天然更新障碍的发生，轻者降低天然更新的效果，重者导致树种的灭绝。陆均松属罗汉松科树种，是优良的用材、环境保护和园林绿化树种，我国仅在海南岛有分布，是海南岛热带山地雨林标志树种之一。《中国珍稀濒危植物红皮书》将其列为三级保护植物。1995年调查，海南岛天然陆均松群落中分布大量的中大径级立木，而中小径级立木及幼苗幼树十分缺乏，表明其天然更新出现严重障碍问题。为此，本项目将采用陆均松天然林现状调查和林下、林窗人工播种更新试验对比的方法，研究不同生境条件下陆均松天然更新的种源、种子雨、种子库、幼苗成活和幼树生长的特征，揭示陆均松天然更新障碍的生物抑制、生境限制和自然、人为干扰机制，为珍稀濒危树种陆均松天然更新障碍诊断和种群的保护、恢复与发展提供理论、技术和方法支持。

本项目通过对研究区陆均松资源、更新幼苗幼树、群落生境、种子产量与品质、种子雨、种子库、枯落物化感等调查、观测和分析研究，揭示了陆均松天然更新障碍因素及影响机制。（1）种源障碍，陆均松种子产量少、品质低，缺少足够的健康种子；（2）动物障碍。大多数陆均松成熟种子在脱落前被动物啃食，进一步加重了陆均松天然更新种子的不足。（3）年龄障碍。陆均松老树多，青壮年树少，健康种子生产的母树缺乏；（4）生境障碍。林分郁闭度大、阴坡及陡坡等形成的林地温度低、湿度大、光照弱、地面固定难，不利于陆均松种子保存、萌发、幼苗幼树的生长；（5）化感障碍。陆均松群落中的香润楠、乐东抑单性木兰、白花含等的枯落物对陆均松种子萌芽不利。本项目研究成果包括5篇已发表论文、2篇已录用论文，4篇在审论文，1部专著已出版，2名硕士研究生已毕业。本项目研究成果可为陆均松资源的保护、恢复和可持续发展提供科技支撑，可为森林天然更新障碍机制研究提供方法参考。