Mapping forest type and age in China's plantations.

Area of Science:

• Forestry Science
• Remote Sensing
• Ecology

Background:

• Forest age is critical for accurate carbon (C) stock and uptake quantification, particularly in China due to its extensive fast-growing plantations.
• Existing forest age maps lack the spatial specificity required for plantation analysis, hindering precise C stock dynamic assessments.

Purpose of the Study:

• To develop high-resolution (1-km) forest age and type maps for China's plantations.
• To quantify spatial uncertainties associated with these maps using diverse data sources.
• To assess the influence of human management on forest age reconstruction.

Main Methods:

• Integration of field-measured data, national forest inventory data, digitized forest maps, and remote sensing-derived forest height data.
• Development of spatially explicit 1-km resolution forest age and type maps.
• Spatial uncertainty quantification using validation data.

Main Results:

• National average forest plantation age in 2005 was estimated at 16.5 years, closely aligning with national inventory data (16.6 years).
• Human management practices were identified as a significant factor in reconstructing forest age maps, a previously overlooked aspect.
• Substantial spatial uncertainties were detected, indicating a need for improved mapping methodologies.

Conclusions:

• The developed forest age and type maps provide a valuable resource for C stock simulations in China.
• Consistent use of forest age and type information in simulations is recommended to prevent biases.
• Further research is essential to refine forest age and type mapping and reduce associated uncertainties.