15 Year Critical Stages Remeasurement
Description: Intensive silviculture in high-yield plantations requires close attention to the management of competing vegetation. A recent review of long-term studies around the world indicates 30-500% yield gains from effective vegetation management. To achieve these yield gains however, requires a sound understanding of the optimal timing and duration of vegetation control necessary during the early establishment and growth phase of a forest plantation. Knowing the best timing and minimum duration of vegetation control can help forest managers reduce 1)treatment costs, 2) unnecessary herbicide use, 3) variation in treatment success, and 4) any negative ecological effects associated with vegetation control.
A critical period of interspecific competition study was established outside of Sault Ste. Marie, Ontario in 1992 to address the question of the optimum timing and duration of vegetation control for Jack Pine, Red Pine, White Pine, and Black Spruce plantations. It is the longest running study of its kind in the world and has been replicated as far away as Oregon and Australia to determine these relationships on other forest systems. The critical period (CP) is the time period during stand development when competing vegetation must be controlled to prevent significant yield losses in early stand growth.
It is vital that Ontario forest managers acquire long-term growth and yield data to determine the kinds of yields that are possible from intensive silvicultural prescriptions in young forest stands. Earlier results from this study reported the 3 and 5 year growth responses. Wood volume growth and CP patterns were recently reported for the 10th year for this study. These results indicate that early stand growth can more than double for jack pine, red pine, white pine, and black spruce plantations if vegetation is controlled for only the first few years after planting. The CP patterns established during the first decade also appear to hold for the first decade of stand development.
The 15th year of growth was completed in the fall of 2006 for the Ontario CP study. It was vital that tree growth and survival were measured on this study to provide long-term data for improving growth and yield predictions that are possible under intensive silvicultural regimes. It was also vital to determine whether the CP of competition determined in the early years of stand development are being maintained over time.
The objectives of the study then, were to measure, analyze, and report te 15th year stand growth from permanet study plots of the Ontario CP study and to transfer the results to forestry practitioners across the area of undertaking.
The Project Team: Doug Pitt, CFS, Robert Wagner, University of Maine, Al Stinson, MNR-FRP.
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