Journal of Forestry Research, 15(1): 39-44 (2004) 39

Living characteristics of rare and endangered species ¾ Davidia involucrata

WU Gang*, HAN Shan-heng, WANG Hong-chang, LUO Yue-chu, DENG Hong-bing, ZHAO Jing-zhu Key Laboratory of Systems Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China

Abstract: Dovetree (Davidia involucrate), one of the first-class protective in China, is a relic species of paleotropical kingdom in Tertiary period, belonging to Davidiaceae with a single . In recent years, the increase of regional developing projects has led to a sharp decrease of this ancient and rare in naturally distributed habitats and natural population. In this paper, the biological and ecological characteristics of Dovetree were described, and the geographically distributed condition of this species in different geologic periods as well as the major reasons for dynamic changes of its population were systematically analyzed in accordance with field researches and references. The investigations conducted in different years by setting up standard sample plots showed that the population number of Dovetree increased yearly in the areas without human interference but decreased yearly in the areas with human interference. With the increase of population density and human activities de- creased as the logarithmic curve: Y = -100.7ln(x)+178.09, and it has turned from a dominant population into an endangered population. Based on the former and present studies on Dovetree, some protection strategies were put foreword for protecting this ancient and rare species. Key words: Davidia involucrate; Dovetree; Geographical Distribution, Biological Characteristics, Protection Policy CLC number: S718.4 Document code: A Article ID: 1007-662X(2004)01-0039-06

1994,1995). In 1921, New York Nature Museum of America delegated persons to collect seeds and specimen of rare Introduction flowers and rare plants in China. They transported some

Dovetree seedlings back to America and planted them in Dovetree (Davidia involucrate Baill), which is rated as the White House (Zhang 1995). In June of 1954, Chinese first class protective plant in China, is a tertiary paleotropi- Premier Chou Enlai thought highly of the beautiful scene of cal kingdom relic species rare to China (Fu 1992). It be- Dovetree in bloom during Genevese Meeting. When he longs to Davidiaceae with a single genus, and its system- learned that its ancestral home was China, he directed atical position is relatively solitary. Dovetree is usually re- Chinese forestry researchers to carry out the research and garded as a "Botanic Living Fossil" and also called Chinese propagation of Dovetree (Yang 1980). However, up to date, dove , because its capitulum with two beautiful is the research on this rare species has been still being in the exactly like a flying dove (Yang 1986; Zhang 1988). beginning phase because of lacking ecology and environ- Southwest of China is the original place of the Dovetree ment data. In this paper, we discussed the biological char- (Tao 1986; Zhang, 1992; Zhang 1995). In 1869, Armond acteristics of Dovetree, systematically analyzed the natural David, a French priest, found a solitary tree in Muping of and artificial disturbances in different geologic periods to its Sichuan Province. He delivered articles and regarded that survival, and probed into conservation policy on this spe- Dovetree was distributed only in Muping and Shennongjia cies. The objective of this paper is to provide basic data (Wang 1995); nevertheless, the correctness of this report such as phenology, regeneration and community charac- was doubtful because of the hard transportation in South- teristics, for intensively studying and introducing the rare west China (He 1995). In 1904, Qi'an Company of the species, protecting species resources and genes, and all of United Kingdom delegated Wilson to collect this rare tree relic species in Southwest of China. and made an exploratory search in Southwest China. He fully completed the task and presented it to Anderrow Ar- Biological and ecological characteristics boretum of Harvard University. Wilson also delivered a masterpiece of Mother of Chinese Gardens (Zhang Biological characteristics Dovetree is low-rooted lofty defoliated arbor tree. Its av- Foundation Item: This research was coordinated by the National Natural Science Foundation of China (No. 39970591) erage height is 10~25 m, and the maximum height reaches Biography: WU Gang* (1965-), Male, Professor in Key Laboratory of to 30 m. DBH (Diameter at Breast Height) can reach Systems Ecology, Research Center for Eco-Environmental Sciences, Chinese 1.0-1.5 m. Dovetree is a hygrophilous plant species. Before Academy of Sciences, Beijing 100085, China. [email protected] Received date:: 2003-11-26 the age of 10, it does not have obvious taproots andbranch Responsible editor: Chai Ruihai

40 WU Gang et al. roots, and its root system is greatly distributed in 10-20 cm example, Castanopsis hunii, Cyclobalanopsis oxyodon, and layer of soil. When Dovetree is fifteen to thirty years old, its Lithocarpus sp. are prevalent. The proportion of evergreen taproots only reach 0.8-1.5 m in length and branch roots broad-leaved in the lower arbor layer greatly in- compress 30-70 cm soil. The root's distributing breadth is creases, but they are frequently little arbors such as Ca- about 10-15 cm (Wang 1993). Dovetree begins to bloom mellia cuspidata, Symplocus stellaris, Eurya sp., Camellia when it is 6-8 years old, fruit at age of 10-15, with a fruiting pitardii, Michelia sp., Sorbus sp. and the seedlings of up- peak at age of 30~90, and for isolated cases, some indi- per-layer arbors. The species of Styrax hypoglauca or viduals even bloom and fruit at age of over 100 years. The Pterostyrax psilophylla of Styracaceae in the arbor layer is buds of natural individuals sprout in the last ten-day of well developed. The tall Pterostyrax psilophylla can be February, enlarge in the first ten-day of March, completely regarded as a reference species to find Davidia involucrata. outspread in the last ten-day of March, begin to grow in the The shrub layer, with a coverage degree in range of middle ten-day of April until the middle ten-day of May (The 30%-60%, is composed of the species: Litsea sp., Lindera length of leaf stalk is 4-8 cm, the width of leaf surface is glauca, Lindera fragrans, Euonymus alatus, Rubus peltatus, 9-16 cm); spring cycle shoots grow in the middle ten-day of Mahonia bealei, Weigela japonica, Callicarpa cathayana, April until the first ten-day of July (the length is 20-55 cm), Stachyunus chinensis, Dichroa febrifuga, Sambucus wil- fall cycle shoots of exceptional individual grow in the first liamsii, Hydrangea chinensis, Ilex cornuta, Biburnum sp., ten-day of August until the first ten-day of October (the Aucuba chinensis etc. There is also Sinarundinaria sp. and length is 5-10 cm). The blooming period ranges from the Rhododendron sp. at the higher altitude. middle ten-day of April to the middle ten-day of May. Two The herbaceous layer, with a coverage degree of lower bracts are upstanding: one is usually 10-15 cm in length than 30%, is often occupied by skiophilous and hygrophi- and 7-10 cm in basal width, and the other is 4-8 cm long lous plants, such as Dysosma versipells, Panax transitox- and 3-5cm in basal width. Along with bracts' growth and inus, Arisaema rhizomatum, Dryopteris sp., Arthraxon his- seeds' formation, foot stalks cannot support the weight of pidus, Reineckea carnea, Rohdea japonica, Parix poly- bracts and seeds. Therefore, at this season, foot stalks are phylla, Pilea sp., Elatostema sp., Oxalis griffithii, Catex sp., pressed bending, bracts droop and the color of bracts etc. Interlamellar plants are lichen, Pyrrosia sp., Den- change from light green to white. Under the sun, a is drobium sp., Schisandra sp., Celastrus sp., Cayratia ja- blown by the wind like doves dancing, so the plant is called ponica, Smilax sp., etc. Chinese dove tree. After 10-15 days, bracts fell off. The The remarkable characteristics of Dovetree community is length of big bract is 10-25 cm and that of small bract is that it includes many archaic and rare plants, such as 7-15 cm. The blooming period is about 40-50 days (Sen Davidia involucrata, Tetracentron sinensis, Carpinus 1993; Xiang 1989). sinense, Actinidia chinensis, Celastrus sp., Fagus logipetiolata, Aesculus wilsonli, and Panax transitoxinus, Community composition and structure etc. The distribution area of Dovetree had a great change in elevation, so the species composition of Dovetree forest is Habitat and regeneration very different. There are more evergreen broad-leaved Dovetree grows in the valleys in which relief types are varieties at the lower limit of its distribution. Castanopsis sp., complex, relative relief is great, and erosion is serious; or Machilus sp., Lithocarpus sp. are popular. And many defo- grows in the shady slope of round hill on which hypso- liated broad-leaved trees such as Acer sp., Sorbus sp., graphic feature is slow, and relative relief is small. The Dis- Prunus sp. distributes at its upper limit. tribution area of Dovetree is characterized in climate by Communities dominated by Dovetree are usually found in cold winter, cool summer, less rain in winter and spring but mountain valleys at elevations of 1300-1500 m. The color of spate in summer and fall, dense fog in foggy days, and the community is viridian, while in winter yellow brown and great humidity in the forest. This indicates that Dovetree is rifle green are mixed. Arbor layer, shrub layer, and herba- a cold-resistant, cool-loving, shade-tolerant and moist cli- ceous layer are distinct in this kind of community, and the mate-enduring species in sub-tropic area. It can grow in canopy density of Dovetree forest can reach 0.7. many soil types: mountain yellow soil, mountain yellow The arbor layer can be divided into two sub-layers. The brown soil, brown soil, red and yellow soil. Still in acidic upper layer, about 10-25 m high, is predominantly made up (pH=4.5~6.0), moist, loose and fertile soil with thick humus, of defoliated broad-leaved trees, such as Davidia involu- granular structure, Dovetree also grows well (Liu 1987). crata which is dominant, Strax hypoglauca, Liquidambar Dovetree has sprouting habitats. It will produce many cop- acalycia, and Pterostyrax psilophylla. The community also pice sprouts from neck of spermatozoon if the normal indi- includes Aesculus wilsonli, Tetracentron sinensis, Betula vidual is hurt. In wild type, Dovetree regenerates from insignis, Acer davidii, Acer sinense, Acer palmatum, Jug- seeds and coppice sprouts, but mainly from seeds. Only lans cathayensis, Carpinus fagiana, Fagus logipetiolata etc. when seeds sprout do animals feed on them, as its nut is There are evergreen broad-leaved trees in the upper arbor hard. Therefore the retention of natural seeds is possible layer, but their tree crowns are lower than Dovetree’s, for Our data showed that seeds of Dovetree stored in ventila-

Journal of Forestry Research, 15(1): 39-44 (2004) 41 tive condition, did not germinate, while the germination of ered by the mountainous glaciers of Quaternary Period. A those seeds stored in the wet sand was promoted or ac- lot of vegetation disappeared due to the glaciers of qua- celerated. However, in China, most of distribution areas of ternary period and global temperature drop. Dovetree died Dovetree are dry, and it is difficult for Dovetree to sprout, as out in many place (Zhang 1992), and survived only in sub- a result, its natural propagation is restricted. Only in the tropical mountain of the Southwest China because of com- bottom of deep-cutting valley, where the soil environment plex topography and weak impacts of the glaciers of Qua- was improved, the Dovetree may have chances to propa- ternary Period. This is why the Dovetree is called living gate by seeds. In this condition, other tree species cannot fossil (Zhang 1992) and direct descendant of flora of the be in normal development. This decreases the competition Tertiary Period (Group of Sichuan Vegetation 1980). In between Dovetree and other tree species. And in the com- 1869, French Armand David found Dovetree in Muping in munity with a medium canopy density, the Dovetree could Baoxing County of Sichuan Province. And Dovetree is regenerate successfully if the seed sources are rich. One of named as Davidia involucrata by Baillion H.E. Botanists at the major endangering reasons for this species is that its that time were greatly concerned with this tree species. reproduction requests suitable sunshine condition and soil After that Euramerican scholars came to China to gather humidity and that wild seeding are excavated. seeds. So Dovetree is viewed as a rare and famous orna- mental plant of gardens. Natural and artificial disturbance Through the analysis of palynology and history data (Group of Sichuan Vegetation 1980), after the Quaternary Dovetree in different geological times Period, global temperature increased, the distribution of Angiosperm was well developed from the late cretaceous Dovetree increased only in the sewerage of mountainous period to Tertiary period. Dovetree was developed at the area in the Southwest China. Up to the late 19th century, same time and its Distribution reached Yellow River basin the distribution of Dovetree stretched from Qingzhen at N 37°-38° in the early Tertiary period. After the miocene County in Guizhou Province at 26°46' N to Wen County in epoch, climate turn cold gradually. At that time, the flora Gansu Province at 32°43' N and from Gongshan County in was like the today's (Wu 1979; Group of Sichuan Vegeta- Province at 98°6' E to Changyang County in Hubei tion 1980). To the late Te rtiary period, northeast of Yunnan Province at 111°20' E. Now Dovetree is distributed in seven Province and Southwest of Sichuan Province became a provinces (Gansu, Shanxi, Hubei, Hunan, Sichuan, whole body on topography, which was “peneplain”. Vegeta- Guizhou and Yunnan) and over 40 counties (Shi 1986; Qi tion was an intact flora. Dovetree possibly distributed 1990) (Fig. 1). Nevertheless, in the 20th century, human throughout this area, even the major vegetation type on the activities destroyed the natural forest ecosystem and plant shady slope. Dovetree was widely ranged in the world habitat, which has led to a sharp decrease of natural dis- (Wang 1995). To the early quaternary period, Earth ex- tributed area and natural population number of this ancient perienced some glacial periods. The high latitude and mid- and rare plant. Dovetree is presently in severe danger dle latitude of the northern hemisphere were widely cov- (Zhong 1984; Wu 1985). ered by continental glaciers and mountainous glaciers. Even Jiangsu and Zhejiang provinces of China were cov-

Fig. 1 The vertical distribution pattern of Davidia involucrate

42 WU Gang et al.

natural conservation area. The effects of human activities on Dovetree Since the extinction of dinosaur 65 million years ago, the loss of biodiversity is faster than any other time. It is esti- mated by scientists that at present speed about 5%-10% of tropical forest species possibly die out in the next 30 years. The investigations on dovetree in different years by stan- dard sample plots showed that the population number of dovetree and its reproduction condition are in depression following the increase of population density and human activities (Fig. 2 and Fig. 3).

Fig. 3 The relationship between population density and changes of Davidia involucrata Baill population in intense human interference area Survey area: 2400m2, survey timespan is ten years (1949, 1959, 1969, 1979, 1989, 1999)

How to protect Dovetree: Conservation Policies

It is well known that Dovetree is the famous ornamental Fig. 2 Change condition of Davidia involucrata Baill’s popu- plant in the world. Introduction and cultivation of Dovetree lation number in two test plots in Fanjingshan in Guizhou in the foreign countries were carried out in the late 19th Province of China. century. Now Dovetree in Genevese of Switzerland and This figure showed the difference of dovetree’s population number and White House are in bloom and fruiting. China began intro- reproduction with and without intense human interference in 50 years. duction of Dovetree from the 1960s, including 11 provinces: Curve a and b separately represents the individual plants in five gouges Yunnan, Sichuan, Hunan, Hubei, Anhui, Zhejiang, Jiangsu, without and with human interference. The area of sample plot is 2400 Henan, Shanxi, Shanghai and Beijing (pot culture). From m2 for each kind of investigation. 1988 to1990, three hetero institutional forests were estab- lished: Lijiazai Experimental Area in Jigongshan National From Fig. 2, we can see that without artificial interference Nature Conservation Area in Henan Province (4 hm2), Dovetree population belongs to spreading population. The Houhe Forestry Centre in Wufeng County of Hubei Prov- individual number of population increases as the exponen- ince (13.3 hm2), West Tianmu Mountain Forest Science tial curve: Y=141.38e0.1142 (R2=0.9890). Dovetree’s popula- Institute in Lin'an County of Zhejiang Province. Rate of tion is in severe depression under the intense artificial in- survival can reach 80%. terference. The individual number of population decreases In addition to study on experimental forest for allopatric as the logarithmic decrease curve: Y = -100.7ln(x)+178.09 and cultivated species, an emphasis should be put on the (R2=0.9349). Dovetree population is in severe danger due natural habitat of Dovetree. Dovetree conservation for al- to the intense interference. This species is sensitive to lopatric and cultivated species has already lost many in- exterior environment, and the stability of this community is trinsic genetic biodiversity. While stem planting is just the fragile. The major reason for the sharp decrease of recent transfer of genetic materials. Therefore, to protect species distribution area of Dovetree is that environmental changes diversity and genetic diversity of Dovetree, firstly it is to lead to the difficulty of natural regeneration. protect its natural habitat. The purpose of protecting biodi- From the above analysis, with the increase of people versity is to protect and utilize biological resources through population density, population number of Dovetree de- non-decreasing species diversification or nondestroying creases as the logarithmic curve: Y = -100.7ln(x)+178.09 important habitats and ecosystems. Aiming at ancient and Dovetree population depressed from dominant popula- populations, this process should embody three basic tion to endangered population. Meanwhile, the population compositions: saving biodiversity of Dovetree's community, numbers of most ancient species decrease at a high speed analyzing sustainability of biodiversity of Dovetree commu- because of the habitat destroy. It becomes the major pur- nity, and reasonably utilizing this rare ornamental plant. pose to protect the ancient species through establishing Saving biodiversity of Dovetree community is to protect

Journal of Forestry Research, 15(1): 39-44 (2004) 43 gene, species, habitat and ecosystem. The best measure seeds germinate only on the edge of forest and in humid for protection of this rare species is to protect its habitat. climate. Many people dig up natural seedlings. All of these Therefore, the key problem to protection on the spot is to threaten its survival and development. For this purpose, it is prevent retrogression of natural ecosystem, decrease hu- very essential to strengthen management of natural reser- man activities in natural habitat, and effectively manage the vation area, for example, Shennongjia in Hubei province, conservation area. For this reason, we put forward five Mulinzi in Hefeng County, Xingdoushan in Lichuan County, protection strategies of ancient species, especially the Houhe in Wufeng County, Wolong in Wenchuan County, Dovetree. Dafengding in Mabian County, Dafengding in Meigu County, (1) Establish national policy to improve sustainable utility Small Zaizigou in Beichuan County, Baishuijiang in Wen and protection of special habitat of rare ancient species County in Gansu province, Fanjingshan in Jiangkou County (especially Davidia involucrata). Energetically develop the in Guizhou province, Badagongshan in Shangzhi County in efficiency of utilizing biological resources. Hunan, Huping in Shimen County, Gongshan in Gaoli (2) Create local communities to protect the population of County in Yunnan province, Sanjiangkou in Yongshan ancient species, especially Dovetree. Band Dovetree’s County and Haiziping jin Yiliang County. Meanwhile, we individual protection, population protection, community should emphasize protection in non-native habitat. That is protection, ecosystem protection and habitat protection. to say: strengthen the introduction of Davidia involucrata, Combine protection with scientific research. Bring the living enlarge its distribution area, and relieve the threats caused law of ancient species. by its deficient propagation capability and human affection. (3) Establish a stable society, i.e. background to protect ancient population. Only under the background of material Acknowledgements change from destroying population distribution to sustain- able living, can we ensure adopting tactics to protect the The authors would like to thank Prof. Li Wenhua, aca- ancient species. demician of Chinese Academy of Sciences, the staff work- (4) Protection strategies commonly fall into two broad ing in the Fanjing Mountain Biosphere Reserve, for their categories: simply allowing relatively natural vegetation and helpful information about the reserve. We would also like to ecosystems to acts as nature reserves by keeping land and thank the referees for their helpful comments. Special vegetation management; intentionally setting aside pro- thanks would be given to Dr. Wang Qingli, for his valuable tected areas to act as designated nature reserves. Under recommendations for the paper. the hypothesis of protecting its genes and biological char- acteristics, combine these two protection strategies to in- References crease its living adaptability to habitat and to widen eco- logical behavior. Compiling Group of Yunnan Vegetation. 1987. Yunnan vegetation [M]. (5) Strengthen environmental consciousness, increase Beijing: Science Press, p28-46. (in Chinese) public participant capability, and combine landscaping with Conservancy of Wolong Natural Conservation Area. 1987. Wolong introducing Dovetree. vegetation and plant resources [M]. Chengdu: Sichuan Science and At the same time, it is very necessary to impose restric- Technology Press, p81-82. (in Chinese) Editorial Committee of Chinese Vegetation. 1980. 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ii Chinese Abstracts

有显著影响。就三个水分和热胁迫周期而言，研究发现：在 林覆盖率由 1987 年的 47.6％变为 2000 年的 81.3％。为了 每个水分和热胁迫周期结束时测定的杉木和马尾松(Fv/Fm) 今后林业可持续发展与管理，本文提出了加强防火意识和注 值没有显著差异。但随着胁迫时间的延长，北美乔柏的(Fv/Fm) 重树种多样性培育等对策。图 3 表 3 参 11。 值显著下降。图 4 表 4 参 20。 关键词：景观变化；火烧迹地；大兴安岭 关键词：杉木；马尾松；北美乔柏；叶绿素荧光；水分胁迫； CLC number: S762.1 Document code: A 热胁迫 Article ID: 1007-662X(2004)01-0033-06 CLC number: Q945.17 Document code: A Article ID: 1007-662X(2004)01-0024-05 04-01-007 珍稀濒危树种珙桐的生存特性/吴钢，韩单恒，王宏昌，罗跃 04-01-005 初，邓红兵，赵景柱（中国科学院生态环境研究中心，系统 不同土地利用方式对土壤有机碳、氮含量的影响/王效举（日 生态重点实验室，北京，100085）// Journal of Forestry 本埼玉环境科学国际中心，埼玉，日本 347-0115，日本；中 Research.-2004, 15(1): 39-44. 国科学院应用生态研究所，沈阳 110016，中国），李法云（辽 珙桐(Davidia involucrate) 为中国一级保护植物，系第三 宁大学环境与生命科学学院，沈阳 110036，中国），范志平， 纪古热带植物的孑遗树种，属于珍稀濒危的单属单种植物。 熊在平（中国科学院应用生态研究所，沈阳 110016，中国） 近年来，由于区域开发项目的增多，致使这种古老而珍稀树 // Journal of Forestry Research.-2004, 15(1): 29-32. 种的天然分布生境和天然种群数量急剧下降。为此，本文通 土壤有机 C、N 的定量动态变化是评价不同土地利用方 过大面积的野外调查和查阅资料，研究了珙桐的生物和生态 式对土壤质量影响的重要内容。本文比较了研究地区种植黑 特性，系统分析了珙桐在不同地质阶段的地理分布状况，探 麦草（ Lolium multiflorum Lam.）、百喜草(Paspalum notatum 讨了促使其种群数量动态变化的主要原因。不同年份标准样 Flugge.)、桔树(Citrus reticulata Blanco.)和马尾松(Pinus 地调查表明，在没有人类干扰的区域，珙桐种群数量随年份 Massoniana Lamb.)的四种土地利用方式对植物生物量和土 增加；但是在有人类干扰的区域，珙桐种群数量随年份减少； 壤有机 C、N 多年变化的影响。试验初期，四种土地利用方 随着人口密度和人类活动的增加，珙桐种群数量呈对数曲线y 式的植物生物量几乎处于同一水平。经过 10 年长期试验后， ＝-100.7ln(x)+178.09的速度下降，这表明珙桐种群已由优势 黑麦草和百喜草的累计生物量分别是桔树的 3.68 和 3.75 倍， 种群衰退到濒临灭绝的程度。基于对珙桐的现有研究，提出 马尾松的 2.06 和 2.14 倍。地下部生物量的差异更为明显， 了珙桐的保护措施。图3参31。 黑麦草和百喜草两种草类地下部累计生物量都较桔树和马尾 关键词：珙桐；地理分布；生物特性；保护措施 松高 10 倍之多。这表明草类较之乔木更有利于提高土壤有机 CLC number: S718.4 Document code: A C、N 的含量。土壤有机 C、N 的含量变化主要发生在 0-40 cm Article ID: 1007-662X(2004)01-0039-06 土层。统计计算表明，10 年期间，种植黑麦草和百喜草可使 土壤有机 C、N 贮量每公顷分别约增加 1.5 吨和 0.2 吨，而 04-01-008 种植桔树使土壤有机 C、N 贮量每公顷分别约减少 1.2 吨和 干旱区开发工程引起柽柳植丛扩展现象研究/黄培祐，高瑞如 0.02 吨，种植马尾松使土壤有机 C、N 贮量每公顷分别约减 （新疆大学生命科学与技术学院，乌鲁木齐 830046） 少 0.4 吨和 0.04 吨。表 4 参 10。 //Journal of Forestry Research. –2004, 15(1): 45-48. 关键词：土壤 C；土壤 N；动态变化；土地利用；量化评价 柽柳植物以其适应干旱、盐碱等恶劣环境而自然生繁于 CLC number: S153.61 Document code: A 我国干旱地区，又以其强大的防风固沙能力在干旱区备受关 Article ID: 1007-662X(2004)01-0029-04 注。＂红柳沙包＂是干旱区颇为特异的生物景观。近数十年 来，由于土地开发和樵伐等原因，柽柳植丛逐渐衰退，由柽 04-01-006 柳植丛形成红柳沙包也被严重破坏。从 20 世纪 80 年代至今， 大兴安岭林火迹地景观变化研究/孔繁花（广岛大学国际协力 作者在我国西部干旱区，含甘肃河西走廊西段，新疆两大盆 研究院，广岛 739-8529，日本；中国科学院应用生态研究 地周围的铁路，公路沿线和库尔班通古特沙漠腹地，通过沿 所，沈阳 110016，中国），李秀珍（中国科学院应用生态研 交通线踏查和样地实测，对由建设工程（如修建公路、铁路 究所，沈阳 110016，中国），尹海伟（南京大学城市与资源 等）所导致的柽柳迅速扩展现象进行了研究。 研究发现在修 学系，南京 210093 ，中国）// Journal of Forestry 筑公路推土机作业所形成的洼地积水区有大量柽柳植丛生 Research.-2004, 15(1): 33-38. 长，由工程建设所引起植丛扩展现象的与该区其他地段柽柳 大兴安岭地区是中国非常重要的林区，也是容易发生林 的扩展颇相类似，但已超出其自然分布的格局。这类植物的 火的地区。1987 年 6 月 5 日发生的一场大火，使 1.33×106 扩展有益于中国西部地区的生态建设植被恢复，对遏制风沙， 公顷原始森林被毁，并产生了不同火烧强度的森林景观斑块。 改善西部环境起到重要作用。因而有必要对柽柳植丛扩展现 本文以图强林业局的两个林场作为典型区（124°05′-122 象进行深入研究，探索促进适宜生境柽柳植丛广泛扩展的方 °18′E, 53°34′-52°15′N），通过绘制和比较 1987 年 法和途径。参 19。 和 2000 年数字化的森林组分图，分析了火后森林景观的变 关键词：干旱区；柽柳；开发工程；植被扩展 化情况。本文将森林覆被类型分为 12 类，针叶林、阔叶林、 CLC number: S718.541 Document code: A 针阔混交林、灌木、苗圃、采伐迹地、火烧迹地、农用地、 Article ID: 1007-662X(2004)01-0045-06 沼泽、水域、建筑用地和荒草地。通过研究，得出以下结论： 1）林火迹地已几乎全部演替为其他森林景观类型，林火迹地 04-01-009 主要是通过自然演替成为阔叶林，其次是通过人工演替成为 美国西弗吉尼亚和中国陕西的森林: 森林开发利用和恢复的 针叶林，其余的则大部分演替为沼泽和荒草地。2）研究区森 研究/Jack E. Coster （Morgantown, West Virginia. U.S.A），