The major studies of the Asia Pacific region reviewed in the present study all indicate the need for sustainable management and include some element of sustainability in the elaboration of scenarios. This focus is most commonly implied with respect to Malaysia, and secondarily for Indonesia. However, the adjustment from current (status quo) forest management and harvest levels to sustainable levels is not explicitly determined, either with respect to timing (how soon) or what the underlying motivating parameters are likely to be - policy or otherwise. Further, the path or transition to sustainability is largely conjectural. For Malaysia, significantly large downward adjustments in harvest are implied. Status quo rates of harvest can be maintained for some period of time based on present inventories but only at the expense of significant declines after 2005 as simulated by Perez Garcia for both ITTO (1993) and the World Bank (1992).
There appears to yet be relatively little consensus on what sustainable management means in terms of long run yields, primarily due to differences in the assumed land base available for management and the levels of investment in technology and management. For example, estimates appear to vary for Indonesia from 25 million cubic meters (constant natural forests) to as much as 32.8 million cubic meters (investment and plantation development). Estimates for Papua New Guinea vary from 5 million cubic meters (as much forest management "as possible") to over 15 million cubic meters ("all forests"). Estimates for the Philippines, Sarawak, Sabah and Peninsular Malaysia are also conditional on the basis of assumptions about both area and investment.
In practice, it can be assumed that reaching sustainable management levels will be slowed throughout much of the Asia Pacific region because of national interests and forest policies, as well as philosophical differences regarding the practical meaning of 'sustainable'. Informal tabulations of "sustainable" for the purposes of this review indicate outputs varying from about 56 million to 75 million cubic meters for the major tropical producers of Malaysia, Indonesia, the Philippines and Papua New Guinea. This is presumed to be focused on the industrial roundwood component, exclusive of fuelwood although this is seldom made clear in most discussions of sustainability. This compares to a Regional production of an estimated 170 million cubic meters in 1994. The utilization of existing inventory stocks during some period of transition is most critical for Malaysia while the utilization ratio of harvest to inventory stocks is more favorable for Indonesia.
It is possible that the ultimate constraint of sustainability will be policy driven as a true constraint on production and markets, with both the transitional and long term policies yet to emerge. How these political factors will be incorporated into quantitative models of scenarios other than by assumed rates of harvest change as exogenous variables will remain to be determined. The levels of harvest utilized in the ITTO Scenario #2 appear to be above the more conservative estimates of 'sustainable' presently available in the regional literature on this issue.