Bhutan’s Land Cover Maps Updated

The first ever systematic land cover assessment in the country was done in 1995 by the Land Use & Planning Project (LUPP) of the Ministry with funds from Danida. The work on updating the maps was long overdue and the need for the updated maps was vital, a two and half year Land Cover Mapping Project (LCMP) was set up at the National Soil Services Centre (NSSC) of the Department of Agriculture (DoA) in 2008 with the financial support of Nu. 7.00 million from the GEF/WB funded Sustainable Land Management Project (SLMP).  Technical Working Group comprising existing GIS personnel from the PPD, FRDD, RNR-RDCs and NSSC of MoAF was involved in implementing the project. 

The land cover maps were updated through digital image processing of multi-spectral ALOS images (AVNIR-2) from the 2006-2009 winter seasons, combined with other reference materials and extensive ground truthing exercises. In order to ensure a reasonable level of precision, a system accuracy assessment was carried out by comparing randomly selected referenced pixels. An overall acceptance level of map accuracy was set at 85%.

The LCMP (2010) land cover assessment shows a national forest cover of 70.46%, of which 62.43% is broadleaf, 22.69% is mixed conifer, 6.77% is fir, 3.98% is chirpine, 2.96% is blue pine and 1.16% is broadleaf with conifer. The shrubs constitute 10.81%, while cultivated agricultural land and meadows account for 2.93% and 4.10% respectively. The snow cover constitutes 7.44% while bare areas constitute 3.20%. Degraded areas, water bodies, built up areas, marshy areas and non-built up areas constitute less than 1% each. Within the 2.93% of cultivated agricultural land, Kamzhing dominates with 61.90% followed by Chhuzhing with 27.86% and horticulture land with 10.24%.

The LCMP (2010) assessment shows significant difference in land cover figures from the LUPP (1995) assessment. In particular, the total forest cover has increased from 64.36% (based on the country’s area of 40,077km²) to 70.46% (based on area of 38,394km²) with an actual area increase of 1,265.9km². However, if we include scrubs in LUPP (1995) and shrubs in LCMP (2010) assessments, the total forest cover would increase from 72.49% (based on 40,077 km²) to 80.89% (based on 38,394 km²).  The cultivated agricultural land on the other hand has dropped from 7.85% (based on 40,077km²) to 2.93% (based on 38,394km²) with an actual area decrease of 2,020 km².

The change in land cover figures is mainly attributed to use of improved land cover assessment methodology in the current land cover assessment (LCMP 2010). In the LUPP (1995) assessment, all the images were manually classified and as a result, most of the land cover types were over-classified viz. cultivated agricultural land. Other factors such as fluctuation in snow cover, urbanization and fallowing of Tseri land have also contributed in altering the land cover figures.

For public information, NSSC of DOA is in the process of printing the land cover maps and the land cover atlas of Bhutan. Once the printing is completed, all these maps and land cover atlas of Bhutan will be made available to ministries, departments, agencies, Dzongkhags and Gewogs that may require and request for the maps for various planning and monitoring purposes.

The 102^nd Cabinet Meeting of Government held on 31 May 2011, approved the new Land Cover Maps of Bhutan.

Source: Ministry of Agriculture and Forests, Royal Government of Bhutan