Epsilon Archive for Student Projects

Abstract

As part of the official Swedish statistics, a figure of the annual gross felling is presented which provides the volume of felled trees within the country for each year. Two figures are annually produced in Sweden: one official figure produced by the Swedish Forest Agency (SFA) and one by the National Forest Inventory (NFI). The annual felling estimates provided by the SFA and the NFI have differed to some extent during the past decades. In this report, the two methods for estimating the national annual gross fellings are described. Possible avenues for improving the gross felling statistics produced by those two methods are suggested. In particular, one of the possible errors in the NFI data is the determination of felling season. An evaluation is made of a method to assess the accuracy of the NFI felling season determination. The test suggests that NFI classification of treatment type is good, that final fellings are usually noticed, but that both thinnings and cleanings are not noticed as often as expected from forest company stand registers. Using stand registers as the truth, unnoticed plots could amount to an underestimate of NFI's felling statistics by approximately 26%.