National Forest Inventory Nepal, 2014

A hybrid approach of two phased stratified systematic cluster sampling design was adopted in the forest inventory through interpretation of satellite images at the first phase and measurement of forest characteristics in the field at the second phase. Five physiographic regions named- Terai, Churia, Middle Mountains, High Mountains and High Himal were considered as strata.
At the first phase, a total of 9,230 clusters were laid out systematically at the nodes of 4 km × 4 km square grids placed across the country. Each cluster was composed of six plots. The first of the six plots was situated at a grid node and two other plots were each locatedl 150 and 300 m respectively, northward of that plot. A parallel set of three plots was situated 300 m east of the first three. Clusters were numbered sequentlly from west to east, followed sequentially from south to north across the country. Within each cluster, plots were numbered from south to north, assigning plot numbers 1, 2 and 3 to the west and 4, 5, and 6 to the east. In some cases, where plots crossed international borders, fewer than six plots were identified. In this way, 55,358 viable plots inside Nepal were identified longitudinally, then latitudinally, and by cluster number. Each plot was classified according to FAO Land Use Classes and reachability through visual interpretation of Google Earth imagery.
The second phase samples were a sub-sample of the first phase samples. A total of 450 clusters (1,553 plots) in Forest were measured. Altogether, 2,544 plots including 1,553 in Forest and 105 in Other Wooded Land were permanently established and assessed whereas 886 plots on Other Land were measured.
Each plot consisted of four concentric circular nested subplots (CCSP) of different radius, four vegetation subplots, four shrubs and seedlings subplots, and four soil pits. Seedlings, saplings and shrubs were measured in four circular subplots, each with a radius of 2 m, located 10 m away from the center of the plot in each of the four cardinal directions (North, East, South and West). Species-wise stem counting, and mean height estimations were carried out for tree and shrub species having DBH less than 5 cm. Information on non-woody vascular plants was collected from four 1 m2 subplots, each located 5 m away from the center in the four cardinal directions. Dead wood was assessed in a circular subplot with a radius of 10 m from the plot center. Fourteen categories of natural and anthropogenic forest disturbances were assessed through field observations of both their occurrence and intensity (severe, moderate, minor) in the 20 m radius subplot. Four soil pits per forest stand were prepared to identity soil texture and to determine soil stoniness. Soil, litter and debris were collected as composite samples by combining the materials collected at all soil pits.
Measuring trees: Subplot radius 4 m- DBH limit (cm) 5.0-9.9; subplot radius 8 m- DBH limit (cm) 10.0-19.9; subplot radius 15 m- DBH limit (cm) 20.0-29.9; subplot radius 20 m- DBH limit (cm) >30.0. More information is available in the adjacent documentation.