Effects of parcelization on land cover in Alamance county, North Carolina

Background/Question/Methods

One of the great challenges in land use science is linking patterns to process.  Historically, most land use change studies have focused on pixel-based analysis involving satellite classifications and GIS-based raster analysis. While powerful modes of analyses, pixel-based analysis is fundamentally disconnected from the spatial scale at which landowners make decisions. Parcels are a much more appropriate unit. Given that most local governments have developed GIS-ready parcel data sets since the late 1990s or early 2000s, this provides a new opportunity to link landowners to land change patterns. In this study, we analyzed land subdivision and forest areal change in Alamance County, North Carolina, between 1999 and 2010. We then linked these patterns to recent trends in forest management practices to assess how land subdivision might be influencing regional-scale forest management.  Data sets included county-level parcel data from each year, 2001 and 2006 NLCD classifications, and 2010 and 2013 Landsat-derived forest classifications. 

Results/Conclusions

Data from 1999 showed there were 62,225 total parcels, with the greatest number of parcels in the 0.5 acre category. In 2002, the 0.01 acre category had the highest frequency  with 61,552 total parcels. In 2006 there were 66,770 total parcels, with the greatest number of parcels in the 0.01 category. The percent forest in 2002 was 31.5% while in 2006 the percent forest was 30%. Although this difference was not significant, a general trend of loss of forest due to parcelization was observed. In 2001 and 2006, overall percent developed land decreased with increasing parcel size class. Also, in the 20-50 ac size class, crops composed 23.86% of the total land cover of split parcels in 2001. Size of parcels also yielded interesting results, specifically, the percent area of developed land decreases with increasing parcel size. This data is important when considering the continuous forestation of land in the Piedmont region of North Carolina. This is especially apparent in the smaller parcel size classes. From a conservation perspective, land-use change and parcelization in critical areas such as the wildland-urban interface will be important for protecting habitat connectivity and continuity.