Heritage Trees Research Articles

Spatial differentiation and landscape-ecological assessment of heritage trees in urban Guangzhou (China)

Recent rapid urbanization of Guangzhou in south China has degraded its rich urban-tree endowment, scattered in roadside, park, and public and semi-public grounds. Based mainly on age, 384 outstanding trees of 25 species were officially designated as heritage specimens. They were evaluated in the field for tree dimensions and habitat types to establish landscape-ecological impacts and spatial differentiation by districts and landuses. To aid the analysis, new quantitative indices were developed, namely landscape-ecological value (LEV), biomass–landscape congruence (BLC), and species spatial differentiation (SSD), respectively, for species presence, abundance, fidelity and clustering. Cultivated natives and five common species dominated heritage trees, accompanied by 11 rare and 9 single ones. Comparisons between the urban- and the heritage-tree populations, and between the LEV of individual species, indicated the uniqueness of heritage species composition and relative landscape-ecological contributions of species groups. Tree count, LEV and species diversity increased markedly with district age, culminating in the second oldest district and then declined somewhat in the oldest; species richness peaked in the mature district and dropped in the old and oldest. Older districts had a narrow range of similarly stressful habitats accommodating mainly inherited old trees; mature districts had more diversified habitats and a dual provenance of inheritance plus recent recruits; young districts had few of both types. Stressful roadside landuse was dominated by tree count, but it was poor in species diversity and richness, and had a rather monotonous native-foliage character. Park provided ample opportunities for a complex species cohort of disparate geographical origin, dimension, age, and amenity function, but its species diversity fell short of expectations. The public and semi-public grounds harboured mainly common species except religious grounds which had higher species diversity and some notably large and unique trees. BLC and SSD results echoed the differential operation of environmental and human influences on tree biomass, configuration and landscape impacts, resulting in notable variations between districts and landuses. The management implications of the results and prognosis for the future of urban heritage trees were explored with reference to Guangzhou and other cities.

Can Genetic Engineering Help Restore 'Heritage' Trees?

BIOTECHNOLOGYBy the end of World War I, the American chestnut, which once dominated many eastern forests, had nearly been wiped out by the Asian fungus Cryphonectria parasitica . Now, forest-biotech researchers believe genetic engineering might help restore this majestic species--and possibly other heritage trees menaced by disease, including elms, white pine, butternut, and several species of California oak.

Estimating the Willingness to Pay for Water Services in Developing Countries: A Case Study of the Use of Contingent Valuation Surveys in Southern Haiti

Progress in improving the quality and quantity of water used by people in rural areas of the developing world has been unsatisfactory in two respects: (1) supplies that have been built are frequently neither used correctly nor properly maintained and (2) extension of improved service to unserved populations has been slow. Though this poor record is not the result of a single factor, a major impediment to improved performance is inadequate information on the response of consumers to new service options. The behavioral assumptions that typically underlie most rural water supply planning efforts are simple. It is commonly assumed that so long as financial requirements do not exceed 5% of income, rural consumers will choose to abandon their existing water supply in favor of the "improved" system. Several reviews by the World Bank, bilateral donors, and water supply agencies in developing countries have shown, however, that this simple model of behavioral response to improved water supplies has usually proved incorrect.1 In rural areas many of those "served" by new systems have chosen to continue with their traditional water use practices.