摘要
沙地樟子松是三北防护林工程中最重要的常绿针叶造林树种。然而,自20世纪90年代初起,最早引种的沙地樟子松人工林在林龄30~35 a后出现枝梢枯黄、长势衰弱、病虫害发生、继而全株死亡且不能天然更新的衰退现象。以科尔沁沙地的樟子松疏林草地和呼伦贝尔沙地的樟子松天然林为参照,以热扩散、稳定同位素和遥感监测等技术开展的系列研究,基本明确了樟子松人工林衰退机制。本文对以往相关研究结果进行了系统总结:确定了沙地樟子松人工林严重水分胁迫的土壤含水量阈值(20%田间持水量),阐明了沙地樟子松人工林水分利用策略(9~21年生樟子松人工林仅利用土壤水,而31~41年生既利用土壤水也利用地下水),明确了沙地樟子松人工林水量平衡特征(水量失衡,吸收至少39mm地下水方能维持水量平衡),量化了樟子松人工林耗水对区域水资源消耗的贡献(消耗12.3%水资源),揭示了樟子松人工林衰退过程,找出了樟子松人工林发展存在的问题及产生的原因。在此基础上,提出了解决衰退对策与营林方案,为防止现存沙地樟子松人工林衰退、合理经营,未来该林种合理布局提供参考。
Pinus sylvestris var.mongolica（MP） is the most important evergreen conifer tree species for afforestation in the Three North Shelter Forest Program.Since the beginning of 1990 s,however,the MP plantations in the earliest introduced area（more than 30-35 years old） have declined,which are characterized by withered top,low growth rate,dead stems and no natural regeneration.A series of experiments in comparison with the sparse MP-grassland in Keerqin sandy land and natural MP forests in Hulunbeier sandy land have been conducted by using thermal dissipation,stable isotope and remote sensing technologies.As a result,the mechanisms of the decline of the MP plantations have been almost determined.In this paper,we systematically summarized the previous results about the decline mechanisms of the MP plantations.The major conclusions are as follows：the soil moisture threshold of severe water stress for the MP plantation was determined（20% of field capacity）;the water use strategy（9-21 years old trees only used soil water,but 31-41 years old trees used both soil water and groundwater） and the water balance of MP plantations（water imbalance,39 mm of groundwater was used to maintain water balance） were tested;as well as the contribution of transpiration of MP plantations to consumption of water resources at a regional scale was quantified（consuming 12.3% of total water resources）.Finally,the decline processes of the MP plantations were revealed.Based on these findings,countermeasures solving the decline of MP plantations and afforestation programs have been proposed,which provides reference for preventing decline and rational management for existing MP plantations,and spatial layout for this tree species in the future.
出处
《生态学杂志》
CAS
CSCD
北大核心
2017年第11期3249-3256,共8页
Chinese Journal of Ecology
基金
中国科学院前沿科学重点研究计划(QYZDJ-SSW-DQC027)
国家自然科学基金项目(31025007
31300592
31400614)资助
关键词
沙地樟子松
衰退
水分胁迫
水分利用策略
Pinus sylvestris var. mongolica
decline
water stress
water use strategy
