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One of the consequences of managing fast-growing forests has been a significant decline in wood quality. The managed resource is usually characterized by younger age, smaller stem diameter, larger taper, larger knots, higher juvenile wood content and different wood characteristics and processing properties. As quality has a profound impact on wood processing, end-product quality and marketing, the changes in wood quality have triggered a chain reaction that includes lower productivity and end product quality and higher production costs. Some wood quality attributes appeared to share a unique link. Stem diameter, stem shape, stem taper and tree age are related to stem and log characteristics; wood anatomical and chemical characteristics constitute basic wood characteristics; gross wood characteristics (e.g., juvenile/mature wood, sapwood/heartwood) refer to woods that are distinctly different in the basic wood characteristics; others are either wood physico-mechanical properties or service-related attributes that are virtually determined by the basic wood characteristics.

On the other hand, most wood quality attributes are somehow interrelated, and thus any attempt to group them into categories appears somewhat arbitrary. In general, gross wood characteristics are related to stem and log characteristics (e.g., age, diameter). For example, juvenile wood and heartwood content usually increase with increasing age or diameter. Reaction wood is often associated with stem shapes or straightness. Since gross wood characteristics are related to stem characteristics, the basic wood characteristics of a stem depend, to some extent, on the stem characteristics. This implies that, for a given species, stems and logs of different ages or diameter classes have different wood characteristics at the gross, anatomical and chemical levels, which suggests that these stems or logs may have different physico-mechanical properties and service-related attributes (Zhang, 2003).

The main R&D questions raised by these changes are :

• Can forests be managed efficiently to produce the wood quality desired by manufacturers?
• How can a different resource be used efficiently to manufacture the quality products desired by customers?
• Is it possible to combine the wood quality needs of different sectors into the same forest management for shared wooden resource ?

Zhang, 2003, XII World Forest Congress.