I am familiar with gbh-density distribution curve method to measure tree population structure, but this method has certain limitations and moreover some species are small sized, some are medium sized and some are larger in size by their life form. So is there any other suitable method applicable to represent the tree population structure instead of gbh-density distribution curve method or is it the best method? .
Hi Gitamani: I think that one of best and quick methods to know the forest structure is the point quarter method. You can apply it to all the strata in which you dived the vegetation. The number of points that you need to have some accuracy depends on the extension of the forest you are studying. You can review Mueller-Dombois and Ellenberg book Aims and methods in vegetation ecology. When you have all the data you can then obtain the relative values of the species and with the three relative values of density, dominance and frequency you can calculate the importance value.
I'd be careful with point-quarter if you want to relate your sample area to the total area again (upscaling)
I think the question aims to the method of data analysis, rather than to the method of collecting data. Certainly, gbh (ideally plus height) of all trees within a square plot is the best data you can get. If you want to compare structures among species and not be confounded by the effect of average (or maximum) size of each species, I think you need to standardise for such species average size. And you may need to do this regardless the particular technique of analysis. Regarding the specific analysis method, you could try comparing cumulative distribution of sizes and perhaps using a regression model to compare slopes among species. If you want to go more sophisticated, I think you could also try a logit (or log-linear) model, so that you can model the distribution of the number of individuals across size classes as a multinomial response variable.
All the best
Thank you @Klaus Gadow. I will go through your paper and definitely I am interested to know more about it.
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