Range and applicability
The CRYPTOS program can be applied to real or imagined forest stands of any size/age composition. However, it is recognized that the theoretical projection capabilities of the CRYPTOS program may be somewhat heroic and some forecasting situations may be without empirical supporting data. Such unsupported simulations may be use of the user, but a brief discussion of the range of stand conditions used to build the growth models will provide the user with an understanding of the foundation upon which CRYPTOS rests.
The growth models imbedded in the CRYPTOS program have been developed from the records of an extensive collection of permanent growth plots located in Del Norte, Humboldt, and Mendocino counties. The majority of growth plots were located in the coastal zone that is subject to fog influence and is commonly referred to as the northern redwood region. By basal area, the average composition of sample plots was approximately 60 percent young-growth redwood, 25 percent other young-growth conifers (primarily Douglas-fir), amd the remainder being comprised of residual old growth and hardwoods. The main species groups (young-growth redwood, Douglas- fir, and tan oak) ranged in composition from zero to 100 percent although single-species compositions greater than 70 percent were mostly restricted to redwood. Very few stands composed of trees under 15 years of breast high age or over 90 years of age were sampled. In terms of stocking, over 85 percent of the sample plots had between 50 and 450 trees per acre. About 70 percent of the sample plots were from apparently even-aged stands with the remainder being from two-storied or multi-aged conditions. About 25 percent of the growth plots had been partially harvested prior to growth sampling.
For stand conditions comparable to the sample data, extensive testing of the CRYPTOS model has indicated a reasonal compliance between simulated yields and empirical growth plot development. Detailed tests are described by Krumland (1982). The relability of the CRYPTOS model beyond these sample ranges is currently unknown and users who are contemplating using the model in such situations are cautioned to do some additional checking.
Previous version of CRYPTOS were developed to run on Digital Equipment Corporation PDP 11/70 and VAX mini-computers. The last version of CRYPTOS (version 4.0) to be released to the public became available in 1982. Since then, as part of a separate research project supported by the Northern California Forest Yield Cooperative, we have developed the California Conifer Timber Output Simulator (CACTOS). CACTOS used much of the theoretical structure and many of the actual parts of CRYPTOS. A logical next step in this evolution was to put the CRYPTOS growth routines into the new simulator. Thus, version 5.0 of CRYPTOS was born.
The work that led to CRYPTOS and CACTOS has depended upon the efforts and money of our industry cooperators. This cooperation effort should continue. THus, we ask every CRYPTOS user to keep us informed of the program use. Also, whenever available, we hope to remain informed of the results of any tests of the CRYPTOS program performed against actual growth data.