Assessing stand density index from national forest inventory data
2012
Eastaugh, Chris S. (University of Natural Resources and Life Sciences, Vienna (Austria). Institute of Silviculture)
Stand density is a key descriptive trait of forests, pertaining to the relationship between the tree size and number per hectare. In 1933 Reineke developed his Stand Density index, and postulated that the log of the quadratic mean stem diameter was linearly related to the log of the number of stems per hectare. Since that time many authors have discussed the meaning of this relationship in terms of stand self thinning, and have offered refinements, rebuttals or support for Reineke’s thesis. Empirical work on stand density however is normally conducted using a relatively limited number of research plots, and often used curve fitting methods that have since been shown to be biased and inaccurate. This study applies modern statistical methods of maximum likelihood estimation to determine the self thinning line for several Austrian forest species and species mixtures, based on a large body of National forest Inventory data collected between 1981 and 2009. Besides possible species differences, the size of the dataset also allows us to study the effects of species mixtures and mixed age stands on the self thinning characteristics of forests. The work is unique in that it is the study into stand density involving a National inventory based on sampling proportional to size (angle-count sampling). Although this introduces some methodological challenges, it also has advantages over a fixed-area based inventory due to the higher probability of the larger, more influential trees being included in the sample.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
المعلومات البيبليوغرافية
تم تزويد هذا السجل من قبل Matica Srpska Library