Identifying Establishment Year and Pre-Conversion Land Cover of Rubber Plantations on Hainan Island, China Using Landsat Data during 1987–2015

Abstract

Knowing the stand age of rubber tree (Hevea brasiliensis) plantations is vitally important for best management practices, estimations of rubber latex yields, and carbon cycle studies (e.g., biomass, carbon pools, and fluxes). However, the stand age (as estimated from the establishment year of rubber plantation) is not available across large regions. In this study, we analyzed Landsat time series images from 1987–2015 and developed algorithms to identify (1) the establishment year of rubber plantations; and (2) the pre-conversion land cover types, such as old rubber plantations, evergreen forests, and cropland. Exposed soil during plantation establishment and linear increases in canopy closure during non-production periods (rubber seedling to mature plantation) were used to identify the establishment year of rubber plantations. Based on the rubber plantation map for 2015 (overall accuracy = 97%), and 1981 Landsat images since 1987, we mapped the establishment year of rubber plantations on Hainan Island (R2 = 0.85/0.99, and RMSE = 2.34/0.54 years at pixel/plantation scale). The results show that: (1) significant conversion of croplands and old rubber plantations to new rubber plantations has occurred substantially in the northwest and northern regions of Hainan Island since 2000, while old rubber plantations were mainly distributed in the southeastern inland strip; (2) the pattern of rubber plantation expansion since 1987 consisted of fragmented plantations from smallholders, and there was no tendency to expand towards a higher altitude and steep slope regions; (3) the largest land source for new rubber plantations since 1988 was old rubber plantations (1.26 × 105 ha), followed by cropland (0.95 × 105 ha), and evergreen forests (0.68 × 105 ha). The resultant algorithms and maps of establishment year and pre-conversion land cover types are likely to be useful in plantation management, and ecological assessments of rubber plantation expansion in China.

Identification of Apple Orchard Planting Year Based on Spatiotemporally Fused Satellite Images and Clustering Analysis of Foliage Phenophase

“…This city is one of the main apple-producing areas in China. Qixia is located between 37 • 05'-37 • 33' N and 120 • 33'-121 • 15' E and covers an area of approximately 2016 km 2 (Figure 1). This area is characterized by a temperate continental monsoon climate with a total annual rainfall of 650 mm and an annual mean temperature of~11.3 • C. The city is dominated by hills and has an average elevation of 178 m above sea level.…”

“…Traditionally, the acquisition of planting age in apple orchards requires the collection of farm planting records or destructive sampling methods. However, although this approach can ensure accurate estimation, it is time-consuming, labor-intensive, and difficult to apply on a large scale [2,3].…”

“…With the development of remote sensing technology, remote sensing data with different temporal and spatial resolutions provide the possibility to classify vegetation and determine its spatial distribution [2,[4][5][6][7]. Remote sensing data have been widely used to determine the age of various types of vegetation.…”

The expansion of large-scale tree plantations: Detection, pathways, and development trade-offs

“…The third group of studies utilizes intra-annual phenology-based algorithms, sometimes in conjunction with supervised 8 classification algorithms, to identify tree plantations. Most of these studies focus on rubber plantations in East Asia where the plantation phenology differs greatly from that of agriculture and natural vegetation during the foliation and defoliation seasons 42,52,53,54 . The final group also uses phenology, but places greater emphasis on inter-annual growth metrics and change events 55 .…”

Editorial for Special Issue: “Remote Sensing of Forest Cover Change”

“…They concluded the differences amongst products were not statistically significant. Chen et al [7] used a time-series of Landsat images (1987-2015) over Hainan Island (China) to identify the establishment year of rubber plantations. They generated maps of plantation start year with a root mean square error of 2.34 yr and 0.54 yr at pixel and plantation scale, respectively.…”