M. Chundnoff and R.L. Youngs
ROBERT L. YOUNGS is Director of the Forest Products Laboratory of the US Forest Service in Madison, Wisconsin. MARTIN CHUDNOFF deals with engineering properties of wood at the same laboratory.
Both temperate and tropical forests have rich arboreal flora, but in the temperate zones only a few species make up the bulk of the growing stock as well as the harvest. Thus, high volumes of salable timber can be removed from comparatively small land areas. In much of the tropics, the harvest has also concentrated on a few species, but with only small volumes suitable for local and foreign markets. Often, 90 percent of the forest volume has a mix of hundreds of species that are considered as non-usable. To further complicate this poor resource utilization, no silvicultural systems that are economically attractive are available to sustain supplies of most current species of choice.
The tradition
Since the beginning of this century, evaluations have been made of the physical, mechanical, chemical and anatomical properties of thousands of timbers, species by species. Most are tropical. There appears to be little relationship between the technical information available and the marketing potential of a species or species group Whether or not testing procedures are standardized may be irrelevant.
Characteristics of the high-demand marketable species harvested in tropical America, West Africa and South east Asia show a remarkable variety of properties. They range from attractive to plain, from high to low strength, from highly durable to perishable, from good to poor quality for machine treatment, from easy to dry to difficult to dry. The only features common to all preferred species are large log sizes and more frequent occurrence in the forest. For example, of the 4 000 tree species found in the Philippines, only 316 are classified as large trees and only 60 are obtainable in quantity. From the marketing point of view, tree size and abundance are more critical than the technological properties of the wood.
End use
Because most lesser used species are few and widely scattered, attempts are being made to increase volume concentrations by pooling species with similar properties for a particular end-use. In Australia, systems have been developed to group many species into a few structural classifications. Research is being done there and in England to define desirable processing and end-use properties for such purposes as joinery, flooring and boat building. Principal component analysis is being used in France and Japan to better define the end-use potential of a species or groups of species. But will this end-use direction solve the problem? Some three decades ago about 30 species from a country in South America, all available in some quantity, were thoroughly tested. Characteristics suitable for a wide array of end uses were documented and opportunities to combine several species were available. Yet, only five of these species are currently selected for the bulk of the harvest.
Timber, as well as other natural resources, is commonly used in order of declining economic quality. This is true for domestic consumption as for exports to foreign markets. It has been established by experience that high current rates of timber consumption do not necessarily force future periods to do without, but rather to incur continuing higher costs because resources of successively lower quality are brought into use. These forces stimulate us to find techniques to defer cost increases by:
· Trying to substitute inputs (African mahogany for Honduras mahogany; light red meranti for okoumé).· Trying to economize on the input (converting veneer peeler cores to lumber and converting residues into panel products; substituting decorative veneers of rosewood for solid wood products).
· Trying entirely different techniques of production (evolution of the pulp and paper industry from a few species suitable to a single pulping method to the qualification of all species using several pulping systems).
Technological developments that make the resource base more homogeneous, as for the pulping example, minimize or erase the restriction once thought inescapable in forest heterogeneity. But such technological developments often require large capital inputs. For local markets, perhaps concern has been focused too much on this problem of lesser used species. As first-choice species become scarce, other species will become attractive for that market. The lesser used species will remain so until their turn comes for market acceptance.
Utilization concepts
Examples of species-oriented and species-tolerant systems illustrate current concern with problems related to the improved utilization of the tropical forest resource. Species-oriented systems are concerned mostly with groupings of timbers for structural applications, but also with a "species-for-the-job" concept that describes properties important for manufacture and performance for a specific end-use and then lists qualifying candidates. The species-tolerant systems are illustrated by the obvious fuelwood-charcoal uses; incising to enhance absorption of wood preservative; strength grouping of structural components based on density or machine stress grading, and processing systems that make any mix of species economically viable to produce a wide array of paper and panel products.
Technological development can help interrupt the present step-by-step species selectivity process and this can be done by focusing on problems such as: developing rapid wood-drying systems that can handle species in mixes of any combination; developing wood-preservation systems that can protect impermeable but perishable species, using substances that are not noxious to people; developing paper-making systems that can be independent of coniferous furnish; developing new fastening systems for dense structural timbers, and much more. But even without such development, the potential exists today to make large volumes of forest resources marketable. This potential could be a tool for devastating forests if it is not used with restraint and care. But, it also offers forest managers an array of options to sustain a productive forest environment.
Any-tree/whole-tree concept
Concepts of marketing by species, marketing for end use, species groupings, and any-tree/whole-tree use can all play significant roles in the improved utilization of the tropical timber resource. But the any-tree/whole-tree concept has the greatest potential for resolving the problem of marketability of "lesser used species" in this decade.
