海岸带多树种结构基干林带的构建及其调控技术研究

STUDIES ON THE STRUCTURE OF MULTISPECIES,ESTABLISHMENT OF TRUNK SHELTERBELT AND ITS CONTROL TECHNIQUES AND EFFECTS IN COAST ZONE

自1992年以来,在福建省东山县赤山林场和惠安县赤湖林场等地海岸沙地,结合木麻黄基千林带更新改造技术研究,对多树种组成结构基干林带构建和调控技术,复层林带培育和冠层结构、多树种组成结构林带混交配置模式和快速成林造林技术以及混交林带防风效益等进行长期试验研究,取得了阶段性的成果。在木麻黄、湿地松混交林混交配置模式早期研究成功的基础上,对其种间关系通过行状疏伐法对林带树种结构比例进行合理调控。调控1年后,通过2个树种树高、直径、单株材积等年生长率的变化分析,提出调控后形成新的混交模式为木麻黄行数应控制在2～3行之内,而湿地松行数应增至3行以上带状混交配置模式,以形成树种间交界行宽行距和树种内窄株距的宽行窄株混交配置模式,对种间关系和林木生长比较有利。这种混交配置模式对新1代多树种混交林带构建有较大应用价值。研究表明,通过稀疏和低效基干林带林下用木麻黄优良无性系、湿地松、厚荚相思等树种进行造林的方法,平均保存率75%～96%,2年生幼林高度为老林带1/3左右,预计2～3a 后可达林带高度,实现对低效基干林带快速更新,并形成多树种组成的复层结构林冠,提高林带防护功能。稀疏低效林带林下造林关键技术为,一是控制林带郁闭度,一般不超过0.4;二是造林后3～4a 间,需对老林带进行疏伐,伐后郁闭度控制在0.2左右。在海岸风口多树种组成结构林带混交配置模式的研究方面,经对多树种多行混交,树种间带状混交和树种间行状混交等3种混交配置模式试验研究结果,认为在幼林期各混交造林树种的生长效果、林带结构特征、种间关系和防风效能等均以前2种混交配置模式较好,幼林保存率90%以上,主要树种树高年平均生长量1.5～2 m,大部分林带2a 内郁闭成林,达到速生和短期内恢复林带的根本目的。研制出以干旱沙地抗旱造林为主的快速成林造林配套技术。经测定2年生幼林,林带前和林带内风降率分别为20%～30%和70%～80%,开始发挥防风作用。研究表明,构建和培育多树种组成结构林带的关键技术,一是必需选用速生和抗逆性强的优良树种和木麻黄无性系;二是进行科学合理的混交配置,试验证明以多树种多行混交和树种间带状混交配置模式较好;三是对混交树种进行树种交介行间宽行距、树种内窄株距的宽行窄株造林配置;四是在林带成林过程中及时进行种间关系调整和密度管理。

In combination with studying on regeneration transforaation techniques of trank shleterbelts was con- ducted a long-term of experiment and research on establishment of trunk shelterbelts from multispecires and its regulation and control,cultivation of compound storied forest,disposition models of mixed forests with structure composed from multispecies,techniques and fast estabishing plantations of protection effects of mixed shelter- belt from 1992.On the basis of success of research on disposition of mixed forest of Casuarina with slash pine, was conducted the retional regulation and control of the structural proportion of species by thinning in row. Based on analysis of the changes of the two species in heght,diameter and single plant volume after one year of the regulation,was presented the new mixed model 2～3 rows of Casuarina and above 3 rows of shash pine, thus formed such disposition:wide row spacing of interspecies,and close plant spacing in the same species. By means of using superior clones of Casuarina,slash pine,Acacia crassicarpa,etc.in the sparse and lower- effective sbelterbelts,the average survival rate of plantations was 75%～96%;the height of 2～annual young growth was one third of the old shelterbelt.The key techniques of planting under sparse,low effective shelter- belts:1.controling crown density,not beyond 0.4;2.thinning the old shelterbelt in 3～4 years after planting, and crown density formed was 0.2 or so.In aspect of research on mixed disposition models of shelterbelt hav- ing the structure from multispecies at wind gaps of coast,the results of researching on 3 mixed models—mixing of multispecies and multirows,mixing in strip system in interspecies and mixing in row system in interspecies showed,that the former two mixed models were better in growth,shelterbelt structure,relation of interspecies and protection effect.The survival rate of young growth was above 90%;the annual average height growth was 1.5m～2m;the crown closed within 2 years.The major techniques of cultivating and eslablishing of shelter- belt with the structure composed of multispecies were 1.application of fast-growing and high adverse-resistant species and superior clones of Casuarina;2.scientific and rational mixed disposition;3.planting disposition of wide row spacing between species and close plant spacing in the same species;4.regulation of relation of spe- cies in time and density controling during growth process of shelterbelt.