Investigating the Effects of Forestry Plans on Tree Diversity Indices Mapped by Kriging Method (A Case Study: Watson Forestry Plan in the Eastern of Mazandaran)

Abstract

Forestry plans have been influential on tree species and planting in different ways, regulating tree species diversity. Investigation of the changes in tree species diversity and preservation livestock sustainability by using forestry inventory can be an appropriate tool for decision makers in management. Indicators such as the Shannon Wiener and Simpson indices can be used to study the variations in tree species diversity in the forest. In this research, the Watson series forestry inventory was used in 2004 and 2014. In the aforementioned years, 369 circular sampling plots were taken with an intensity of 3.3% and using a 200 * 150 m inventory grid with GPS. The Simpson and Shannon Wiener indices were calculated in sampling plots pieces; then, Kriging ability was investigated using histogram, QQ plot, semivariogram and RMSE, and data normalization. The land maps of these indices were analyzed in 2004, 2014; also, their change detections were prepared. The results showed that during the 10-year period of the implementation of the forestry plan, the Simpson and Shannon Wiener species diversity indices were increased by 30%, and about 60% of the area remained unchanged; also, about 11% of the area had reduced species diversity.

Keywords

• shannon wiener index
• simpson index
• variogram
• interpolation
• inventory grid