evaluation of surface sampling method for estimating wood quality (fiber length and density) in standing poplar trees

wood farming and especially poplar plantation is a key answer to the increasing demand of raw materials in wood and cellulosic industries. according to the diversity of wood applications, taking into account the wood quality and grading by wood farmers/buyers as well as its quantity can lead to an optimal management of production and consumption. in this regard, it is necessary to introduce and promote an easy, economic and non-destructive method of evaluation wood and fiber quality in standing trees. in this research, it was tried to clarify whether extracting tiny samples from outer part of a trunk could be an appropriate method for evaluating wood quality of the whole tree. hence, four elite poplar species from five different sites of iran were selected and in each site, cores were extracted from breath height of 20 trees. each core was divided into three parts: near bark, middle, and near pith and fiber length and wood density was measured for each part using conventional methods. statistical analyses showed in most species/sites, there is significant difference between outer part and corresponding average values of a tree in term of measured variables. fiber length and wood density, respectively, were lower and higher in outer part of a tree in comparison to the tree average. however, there was a strong correlation between the values of outer part and tree average and therefore, for each measured property, an equation was proposed by which the poplar wood quality can be estimated knowing the outer part property.