Geospatial Assessment of Potential American Chestnut (Castanea Dentata) Reestablishment -- Presentation Summary

Siyu Zhang

Abstract


The American chestnut (Castanea dentata) was once the dominant deciduous tree species of eastern North America forests. It produced a large amount of seed and lumber and was once regarded as the perfect tree species, having also a positive ecological impact on ecosystems.  At the beginning of 20th century, two exotic fungi, Phytophthora cinnamomi and Cryphonectria parasitica killed great many C. dentata bringing its population to near extinction. By the 1950s, C. dentata lost its historical position as a dominating tree species in the United States forests; and although, some sprouts of this species can still be discovered within its native range, they are usually quickly killed by the blight.  Thanks to breeding techniques, biological control and genetic engineering, advances has been made in effort to produce blight-resistance seedlings, which are projected to succeed in production during the upcoming decades.  Even in the presence of blight-resistance seedlings production the cultivation of C. dentata species requires a full site preparation and a range of intensive management plantation silvicultural treatments. Because of the high costs associated with C. dentata reestablishment, it is important to maximize its successful development by carefully choosing the most suitable sites for its growth.

The presented here study used Multi-Criteria Decision Analysis (MCDA) method to produce a spatial distribution suitability map for the reestablishment of C. Dentata in northeast Georgia.  The results of the analysis suggest that in the investigated study area there is only 3.75% of sites either unsuitable or of low suitability for rebuilding the habitats for C. dentata, while there is 58.98% of sites with high or very high suitability for such habitats, and 37.27% of sites with medium suitability.  The results indicate that soil texture, slope and soil organic matter play the most important roles for C. dentata reestablishment suitability, while climatic factors and soil pH don't play any significant role in suitability of the sites for C. dentata reestablishment.  Although, most of the suitable sites for reestablishing C. dentata are present in forests, particularly with Deciduous tree species, the results of this analysis showed no clear preferences of this species towards any specific land cover types.  Furthermore, C. dentata showed also to be indifferent to most of the topographic condition, and only slope appeared to be potentially a limiting factor if it exceeds 70% on the reestablishment sites, when they become unsuitable for the restoration. This analysis also considers the ownership of the suitable sites to evaluate the potential of the C. dentata reestablishment on our study area.  Of all the suitable sites 72.56% fall within federal lands and 27.44% in private lands.  Deciduous Forest is the main land cover type of our suitable sites owned by both the federal government and the private landowners.  Since expensive treatments are required to successfully reestablish C. dentata, the 27.44% of the land base within the considered area will be subject to the landowners’ consideration of the economic versus ecological tradeoffs, which may affect the reestablishment rate on these lands.


Keywords


American chestnut (Castanea dentata); GIS; multi-criteria decision analysis; suitability score; Cover type mapping;

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