安徽省广德县古树资源特征分析

安徽省广德县现存树龄100 a以上古树923株，隶属于24科38属43种1变种。以枫香Liquidambar formosana数量最多，达322株，超过50株的还有银杏Ginkgo biloba、苦槠Castanopsis sclerophylla、榉树Zelkova schneideriana、糙叶树Aphananthe aspera、朴树Celtis sinensis、黄连木Pistacia chinensis、三角枫Acer buergerianum，其中一级古树14株，二级古树30株，三级古树879株。全县古树种数和株数在年龄上大致呈“金字塔”型分布，总体趋势是树龄越高，科属种数和株数越少，仅有2株树龄超过700 a，树龄最长者约820 a。在这些古树中，大乔木树种最多，其次是中乔木，小乔木和灌木树种稀见，木质藤本类树种最少。古树主要分布在村庄、荒野、路边、河岸和山坡，在村庄分布的古树以栽培和野生起源并重，其余地域分布型则以野生起源为主。该县古树植物区系中，热带性质属10个，占总属数的26.3%；温带性质属20个，占总属数的52.6%，具有南北过渡特征；以东亚和中国特有种占绝对优势，拥有较多的孑遗种、古老种和特有种。

Characteristic Analysis of Ancient Tree Resources in Guangde County,Anhui Province

There are 923 strains of ancient trees at more than 100 years old in Guangde County, Anhui Province, belonging to 43 species and 1 variety, 38 genera and 24 families, with Liquidambar formosana the largest number, up to 322 individuals, and Ginkgo biloba, Castanopsis sclerophylla, Zelkova schneideriana, Aphananthe aspera, Celtis sinensis, Pistacia chinensis, and Acer buergerianum all also more than 50 strains. Among them, 14 strains are classified as ClassⅠunder state protection, and 30 strains as Class Ⅱ, 879 strains as Class Ⅲ. The number of species and strains in terms of age is roughly in Pyramid-type distribution, with the overall trend is that the age higher, the family, genus, species and strains less, and only 3 strains exceed 700 years old including the oldest 820 years approximately. In these ancient trees, the big arbor species are the most, the middle arbor species secondary, the small arbor and shrub species rarely, and woody lianas the least. The ancient trees mainly distribute in village, wilderness, roadside, riverside and hillside. The ancient trees in village are primary from cultivation and wild origin, and in wilderness, roadside, riverside, hillside, are majorly from wild origin. In the floristic elements of ancient trees in the county, there are 10 tropical genera, accounted for 26.3% of total genera, and 20 temperate genera, accounted for 52.6%, which shows some transition characteristic. The species of East Asia and Chinese endemic are the dominant species evidently, with major relict, ancient and endemic elements. According to the research conclusion of ancient tree resources, the species for afforestation and greening in the future in Guangde County are discussed and suggested.