Suitable tract bank size : exploration & estimation

Sammanfattning

The collection of stands planned and ready for harvest, also called the tract bank, gives the harvest manager a selection of stands to choose from while scheduling harvests. Too few and the harvest manager might be forced to make bad decisions; too many bring additional unnecessary costs. However, little research has been done on adapting the tract banks to regional and source-dependent uncertainty, such as contracted harvests or harvests on company-owned land. This study aims to, on a strategic level, per geographic region and source, further the understanding of the tract bank and the uncertainties that effect it. By estimating suitable tract banks using inventory theory, considering outcome deviation and the seasonal differences between planned and harvested stands. The estimates are complemented by regression modelling of the utilisation of stand seasonality classifications, quantified past tract bank sizes and stand storage time. The study finds that forestry is more seasonally constrained northwards in geography compared to the south and in company-owned stands. It also finds that estimated stand volume is systematically underestimated too varying degrees. Moreover, it contributes with quantified regional storage time and regional mean coverage time (months) of past tract banks of a Swedish forest company: North 13,1; Middle 9,5; and South 5,8. Comparably the suitable tract bank sizes estimated in this study are: North 9,5; Middle 5,9; and South 7,1. These results are relevant to those that work with the tract bank, harvest management and harvest planning and could be used in further research of the tract bank.