Number and distribution of large old ginkgos in east China: Implications for regional conservation

Abstract

Large old ginkgos (LOGs), having important ecological, cultural and historical values, are widely distributed in China. However, little is known regarding their quantity and tree-habitat quality in the mesoscale distribution. Here, the quantity, spatial distribution and conservation status of Ginkgo biloba L. older than 100 years in Jiangsu Province, east China were examined using ArcGIS software and detrended correspondence analysis (DCA). Based on our collated data, Jiangsu Province included 2,123 LOG individuals and 237 LOG groves and both mostly occurred in southern and central Jiangsu. Most LOGs grew well and were distributed in villages, temples and government institutions. Ginkgos’ growth status was largely associated with tree-habitat types. LOGs performed worse in commercial areas, roadsides and residential districts than in other tree-habitat types. To protect these ginkgos, dynamic monitoring and strengthening of scientific management are required, especially for tree-habitats in the process of urban planning and construction. It is also necessary to improve the relationship between religious culture and conservation measures. This is the first study examining LOGs in Jiangsu Province using a unified standard and our findings provide a baseline for future studies and insights into the regional conservation of LOGs.

Species Diversity and Distribution Pattern of Heritage Trees in the Rapidly-Urbanizing Province of Jiangsu, China

“…The investigations of ancient trees were made following "Technical Guidelines for Document Establishment of General Survey of National Ancient-Famous Trees". It was issued by the State Forestry Bureau in 2001 and has been widely used in China recently [7,12]. Based on tree ages, three protection categories were classified as tier 3 (100-299 years of age), tier 2 (300-499 years of age), and tier 1 (≥500 years of age).…”

“…According to DBH and tree growth characteristics, we first checked the tree age of each individual, and then removed the records of such trees less than 100 years old. The remained trees were divided into four categories as "good", "fair", "poor", and "dying" by the description of growth status (Table 2) [7,8]. Moreover, nine tree habitat types were classified based on the detailed records of ancient trees' growing sites (Table 3) [1,12].…”

“…Heritage trees, at least 100 years old, tend to be large in size: tree height, crown spread, and/or trunk girth [7]. Therefore, they can form the urban landscape, and create an amenity urban environment for human beings [8,9].…”

“…Currently, the studies concerning urban ancient trees cover a variety of themes, such as field investigation [13][14][15], spatial distribution [7,16], rejuvenation and pest control [17][18][19], and protection legislation [20][21][22], as well as the aesthetic and spiritual aspects of ancient trees [23,24]. Among them, most studies have focused on species diversity and spatial differentiation [7,25]. According to different dimensions, the current studies can be roughly divided into three major categories.…”

“…The former includes longitude, latitude, topography (e.g., average elevation and elevation range shift) [31], and climate (e.g., mean annual temperature, mean annual precipitation, mean temperature of the warmest month, and mean temperature of the coldest month) [33]. The latter (i.e., anthropogenic influence) can be characterized by GDP per capita and population density [7,34]. For example, a recent study demonstrated that the tree density of old ginkgos in China increased significantly with growth of population density and GDP [16].…”