Determination of the Optimum Plot Size to Study the SpatialPatterns of Juniperus Excelsa Trees (Case study: Atashgah, Karaj)

In recent years, new methods have been developed for analyzing spatial pattern of trees, and for verifying the spatial pattern, they need to complete map of spatial location of these trees. The use of these methods depends on study scale in a way that changes in study scale cause changes in spatial pattern. In this regard, present study aims to determine the optimum area of sample plots to quantify the spatial pattern of Juniperus Excelsa M. Beib. In southern facing slopes of Alborz mountains.

A plot with area of six hectares was selected and spatial pattern of trees were evaluated by using g(r) function. In next step, area of plot decreased to five, four, three, two, and one hectare and spatial pattern of trees were determined by using g(r) function and were compared with six hectare plot.

The results of this function indicates regular spatial pattern in trees distances to four meter, cluster pattern at distances of six to ten meter, and random pattern shows in other distances. The results of comparing figures of g(r) functions in different area showed that the overall trend of this functions almost constant up to three hectares. Hence, in this study the appropriate area is achieved three hectares.

It should be noted that in structure studies to determine the best area of plot could reduce time and costs while increasing the precision of the study.