植物生态学报 ›› 2019, Vol. 43 ›› Issue (9): 783-792.doi: 10.17521/cjpe.2018.0232

• 研究论文 • 上一篇    下一篇

模拟氮沉降对北京东灵山辽东栎林树木生长的影响

邹安龙,李修平,倪晓凤,吉成均()   

  1. 北京大学城市与环境学院, 北京大学生态研究中心, 地表过程分析与模拟教育部重点实验室, 北京 100871
  • 收稿日期:2018-09-18 接受日期:2019-02-28 出版日期:2019-09-20 发布日期:2020-01-03
  • 通讯作者: 吉成均 E-mail:jicj@pku.edu.cn
  • 基金资助:
    国家自然科学基金(31770431);国家科技基础性工作专项(2011FY110300)

Responses of tree growth to nitrogen addition in Quercus wutaishanica forests in Mount Dongling, Beijing, China

ZOU An-Long,LI Xiu-Ping,NI Xiao-Feng,JI Cheng-Jun()   

  1. Institute of Ecology, College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
  • Received:2018-09-18 Accepted:2019-02-28 Online:2019-09-20 Published:2020-01-03
  • Contact: JI Cheng-Jun E-mail:jicj@pku.edu.cn
  • Supported by:
    Supported by the National Natural Science Foundation of China(31770431);and the National Basic Work of Science and Technology of China(2011FY110300)

摘要:

传统的元素限制模型认为氮是温带森林生长的限制元素, 不过该结论更多是从地上生物量以及群落水平进行阐述, 忽视了不同物种以及不同径级树木对外源氮的响应差异。辽东栎(Quercus wutaishanica)林是华北地区常见的森林类型, 该研究以北京东灵山辽东栎林为研究对象, 通过设置3个氮添加水平的实验, 即对照CK (0 kg·hm -2·a -1), N50 (50 kg·hm -2·a -1)和N100 (100 kg·hm -2·a -1), 模拟氮沉降对群落和物种水平以及不同径级树木生长的影响。经过7年氮添加, 实验结果显示: 物种水平上, 氮添加明显促进了优势树种辽东栎的生长; 群落水平上, 树木生长随氮浓度增加有不断上升趋势, 但统计学差异不显著; 氮添加显著抑制了辽东栎以及群落内小径级(3-10 cm)树木生长, 中(10-20 cm)、大径级(>20 cm)树木生长随氮沉降水平增加呈上升趋势, 但统计学差异不显著。表明氮是辽东栎以及温带森林树木生长的限制元素; 不同径级的辽东栎和群落内其他植物对氮添加响应不一致, 氮添加抑制了小径级树木生长, 中、大径级树木生长对氮添加响应不明显。

关键词: 氮沉降, 辽东栎, 树木生长, 温带森林

Abstract:
Aims Temperate forest is one of the most important components of the global forests and main carbon pools. Nitrogen (N) is considered as the limiting nutrient for the forest growth. However, the heterogeneities in plant species and stem sizes were largely ignored in previous researches on the effects of N addition on plant growth. Quercus wutaishanica is one of the most common and dominant tree species in the temperate forests in North China. In this study, we investigated the responses of growth of trees and forests to N addition in the Quercus wutaishanica forests in Mt. Dongling in Beijing.
Methods We conducted a 7-year N fertilization experiment in Quercus wutaishanica forests in Mt. Dongling, Beijing, since 2011. The N addition was conducted at three treatment levels, i.e., 0 kg hm -2·a -1, 50 kg hm -2·a -1 and 100 kg hm -2·a -1. Nitrogen was added at the beginning of each month from May to October each year. We used electronic vernier caliper to measure tree growth rate for each year. All trees were divided into three groups based on their diameter at breast height (DBH), namely small trees (DBH = 3-10 cm), median trees (DBH =10-20 cm) and large trees (DBH > 20 cm). Particularly, we considered growth at species level for all Quercus wutaishanica and the growth at community level for all tree species in the stands.
Important findings (1) At species level, N addition enhanced the growth rate of Q. wutaishanica. (2) At community level, the growth rate showed no difference among different N addition treatments. (3) Small trees were restrained, while median and large Q. wutaishanica trees were not significantly influenced, by the N addition.

Key words: nitrogen deposition, Quercus wutaishanica, tree growth, temperate forest