Growing stock levels in even-aged ponderosa pine /

Growing Stock Leve I s in Eve n-a g ed Ponderosa Pine by CI ifford A .Myers Growth of the most widely distributed pine in North America is under joint study by the western Forest and Range Experiment Stations of the U. S. Forest Service.Young, even-aged ponderosa pine ( Pinus ponderosa Laws.) stands are being examined over a wide range of tree sizes, stand densities, and site index.The single plan that co- ordinates activities of the four Stations is an example of how the growing stock problem can be handled for a widely distributed species.The wide range in treatments should provide data needed to answer the questions that arise in evaluation and application of multiple use management of ponderosa pine forests.i itensified management of ponderosa pine for wood products depends on control of growing stock.Such control will permit actual yields of the coast form of ponderosa pine to approach its high potential.The interior form of ponderosa pine occurs in areas of lower site quality, and much of it is subject to stagnation.Saw-log rotations of some dense, young stands may be shortened 60 to 80 years by thinning.Growing stock can be controlled most effectively if stand productivity can be forecast for various combinations of such factors as tree size, stand density, and site quality.Thinning studies, once conducted in almost all ponderosa pine areas, have not provided all the information needed to prescribe growing stock goals.Results from thinned plots have been useful in planning past management and research activities but deficiencies have become more apparent as conversion to managed stands continues.There was usually no attempt to test the low-reserve densities that may be tomorrow's standard.Data were often not complete enough to provide for changes in products or merchantable sizes.Remeasurements were sometimes made at such long in- tervals that the growth information did not indicate results attainable from the frequent cuttings of today.Thinning studies were sometimes planned with economic restrictions as part of the design.For example, thinning frequency and intensity were sometimes determined by the idea that only one thinning was practicable during a rotation.Current