Testing probabilistic techniques of timber volume estimation for forest management planning

• Format: Article
• Language: Italian
• Published: Italian Society of Silviculture and Forest Ecology (SISEF) 2006-01-01
• Series: Forest@
• Subjects: Forest management planning; Timber volume; Two-phase sampling; Relascope; Visual estimation
• Online Access: http://www.sisef.it/forest@/showPaper.php?action=html(8,372)&lang=en

The cost of management plan elaboration is one of the main factors hampering the operational implementation of forest management in Italy. Besides compartment descriptions, such a cost is mainly due to the quantitative assessment of stand dendrometrical attributes. The aim of this work is to test the integration of conventional forest mensuration techniques with probabilistic estimation procedures that in the last years have found ever wider implementation for inventorying small forest areas. Distinctively, the objective of this note is the comparative experimental testing of the following methods of timber volume assessment: two-phase relascope sampling; two-phase visual estimation. Under the examined conditions referred to Turkey oak and beech high stands in Central Italy, the latter method has provided hopeful results. The most accurate and precise options of two-phase visual estimation have allowed an average time saving around 40% with respect to the total tally, with an absolute bias around 4-5% with respect to the true value of compartment timber volume, and efficiency higher than the conventional one-phase systematic plot sampling.