黄土丘陵子午岭针阔混交林隙更新规律

2 0 1 1届本科毕业生毕业论文题目：黄土丘陵子午岭针阔混交林隙更新规律

院系：生命科学与技术学院

学科专业：科学教育

指导教师：张希彪（教授）

作者姓名：雷宏王超赵玉杰

黄土丘陵区子午岭针阔混交林林隙更新规律

雷宏，王超，赵玉杰，张希彪

（陇东学院生命科学与技术学院，甘肃庆阳745000）摘要：以黄土丘陵区子午岭针阔混交林为研究对象，采用样线法研究了林隙的形状、大小、形成方式、形成木的种类、数量、径级、形成年龄、林窗内物种组成及更新状况等。结果表明:该林区林隙砍伐形成方式与海拔呈显著正相关，根拔形成方式与坡度呈显著正相关，林隙形成木的数量与坡向也呈显著正相关，更新树种组成较形成木丰富。在林冠下和林隙内，辽东栎的优势度在更新幼苗物种组成中都居最高，其他依次为油松、茶条槭、杨树。对相对优势度位于前4 位的更新乔木幼苗进行Spearman相关分析，除油松与辽东栎存在显著正相关关系之外，其余种类幼苗间的相关性均不显著，但杨树与辽东栎、杨树与茶条槭均存在不显著的负相关关系；对林隙更新优势度位于前4 位的乔木更新数量与林隙环境因子主成分进行相关分析表明，杨树幼苗更新受地形因子影响较大，油松幼苗更新受土壤养分特征影响显著，茶条槭的更新受地形因子和林隙形成木的特征影响显著，辽东栎幼苗更新与上述5 种环境因子主成分无显著相关性。

关键字：林隙；针阔混交林；更新；优势度

The regeneration rules of coniferous-broadleaved mixed forest gap in

Zi Wu Ling the loess hilly

Leihong ,Wangchao, Zhaoyujie, Zhangxibiao

(College of life science and technology, Longdong University, Qingyang, 745000 ,Gansu) Abstract: Taking the coniferous-broadleaved mixed forest inZi wu ling the loess hilly as the research object, adopt line transects method to study the shape, size, form the way, forming wood species, number, diameter level, formation age, gaps update status within species composition and etc. Results show that: The forest with altitude formed gaps cut way is a significant positive correlation with slope, formed root pulling way is a significant positive correlation with slope angel, the number of gap maker and slope to also shows significant positive correlation, Richness was higher for seedlings than gap makers. the amount of Quercus liaotungensis seedlings is the most in the canopy gaps and within ,others Pinus tabulaeformi s, Acer ginnala Maxim. , Populus. Located on the front of relative advantage degree 4 updates on tree seedlings Spearman correlation analysis, the existence of Pinus tabulaeformis and Quercus liaotungensis is a significantly positive correlation

relationship, other kinds seedlings are not significant correlation between, But Poplar and Quercus liaotungensis, Poplar and Acer ginnala Maxim.there are micro significantly negative correlation relationship . For seedling trees and gap environmental parameters principal component correlation analysis shows that ,the Poulus seedlings was correlated significantly with topographical factors ,while that of Pinus tabulaeformis was affected heavily by soil characteristics, that of Acer ginnala Maxim. was correlated significantly with topographical factors and gap maker characteristics, but Quercus liaotungensis seedling was not correlated significantly with 5 kinds of environmental factors.

Key words: gap; Needle broadly mixed forests; Update; Advantage degree

0 引言

林隙是指1株以上林冠层(主林层)树木死亡而形成的林间空隙，是新个体占据与更新的空间[1-3]。林窗作为森林景观流动镶嵌结构的基础，是不同类型森林更新循环和动态维持的重要因素，也是森林群落苗木更新的主要场所和维持生物物种多样性的重要环境，是森林生态系统长期变化中必不可少的驱动因素[1,2]。由于林窗更新的循环往复使森林处于不断地发育与变化之中，林窗的形成与消亡过程也正是森林不断发育与更新的生态学过程[3,4]。对林窗动态特征的认识，将有助于进一步揭示林窗对森林群落组成、结构和动态的影响及其维持机制[5]。

林隙的形成和变化构成了森林景观的流动镶嵌结构，对植被的正常更新具有重要作用[1，4，5]。林隙作为一种经常发生的小规模的干扰，是森林循环更新的一个重要阶段[6]。作为森林循环的重要一环，林隙已被看成是保护和维持森林群落物种多样性的具体地段和主要场所。

近年来，我国学者已对温带红松阔叶林[6，7]、红松阔叶混交林[8]、亚高山暗针叶林[9~11]、亚热带针阔混叶林[12,13]、亚热带常绿阔叶林[14~17]、常绿阔叶混交林[18]以及热带山地雨林[19]等植被类型的林窗特征及更新进行了大量的研究，但对于以暖温带森林草原为基带的亚顶极群落的油松（Pinus tabulaeformis Carr.）次生林的林窗动态特征及更新状况研究未见报道。本文以位于黄土丘陵区的油松天然次生林群落为研究对象，对其林隙干扰特征和林隙更新调查的基础上，深入探讨了该区林隙干扰环境与更新的关系，以掌握林隙更新规律及其影响因素，对子午岭林区林隙更新特征及规律的研究，有助于揭示子午岭森林演替及发展前途，为子午岭森林更新和可持续经营对策提供科学依据。

1 研究地概况

甘肃子午岭位于黄土高原中心，甘肃省东部，纵跨庆阳地区的华池、合水、宁县、正宁四县，地理坐标为东经107°59′～108°43′，北纬33°18′～36°39′，林区总面积4970.2km2[7]。地势