Jack pine ecosystem productivity project

Description

Research in Ontario, and throughout Canada is attempting to address issues surrounding forest sustainability, and the effects that existing forest management practices are having on the sustainability of both fibre supply and biodiversity. The Jack pine ecosystem productivity project is one of several related North American studies that are placing a long-term and detailed focus on these very important concerns, for a variety of forest species and the sites on which they occur. This type of research is important to forest managers and practitioners in both industry and government because harvest levels and scheduling are ultimately dependent on stand growth and ecosystem health, and hence on site productivity. The underlying scientific knowledge needed to evaluate site productivity is only acquired through detailed and systematic data collection, analysis, and study.

Specifically, the Jack pine ecosystem productivity project is designed to:

• Increase understanding of the principle physical, chemical and biological processes that affect jack pine site productivity
• Investigate the effects of natural and human-caused disturbances on these processes
• Determine how harvesting and site preparation affects the ability of the soil to supply water and nutrients
• Define how current practices can be modified to meet the goal of sustainable forest management
• Identify and investigate opportunities and silvicultural approaches for enhancing site productivity

Forest ecosystem site productivity is a term used to describe the ability of a forest site to sustain healthy tree and vegetation growth. It reflects the combined effects of a number of physical, chemical and biological conditions and processes. Physical conditions include soil moisture, temperature, texture, structure and bulk density, while chemical conditions include soil pH (acidity), organic content, and the presence and amounts of critical elements such as nitrogen, phosphorus, potassium, and carbon. Soil microorganisms, and soil fauna (insects, worms, etc.) are responsible for various biological processes including decomposition and mineralization. All these factors interact in great complexity, and are only now beginning to be thoroughly understood through study and research. This gain in knowledge is leading to a better understanding of over-all site productivity. Forest management practices that affect these processes and their interaction will also affect tree growth. There is a definite need for forest managers and planners to have a sound knowledge of site productivity.

The Jack pine ecosystem productivity project is examining in detail, the processes and factors that effect site productivity, as well as the nutrition and growth of young plantations. Data collected through the study is being used with computer simulation models to determine if sites can maintain long-term productivity in growth (30 to 50 years into the future); in essence, determining whether a harvested site is productive enough to produce future stands of healthy, vigorous trees during future rotations.

Detailed description of work being conducted through the Jack pine ecosystem productivity project:

• Response to a range of disturbances (including soil disturbance and vegetation control
• The effects of forestry practices (whole tree harvesting, tree length harvest, disk trenching, blading, vegetation control on microclimate conditions, seedling growth and related vegetation development
• Nutrient losses associated with various harvesting and silvicultural treatments
• Development, calibration and validation of models to predict long-term soil conditions and health, comparing different harvesting and site preparation scenarios for minimizing nutrient loss
• The effects of different site disturbances regimes on tree carbon uptake and allocation, nutrient use, and soil respiration

The Jack pine ecosystem productivity project includes over 20 experimental sites established on sandy soils in a geographical area between Lake Huron and Chapleau, in north central Ontario. This combination of study sites falls within both the Boreal and Great Lakes – St. Lawrence Forest Regions. The resulting combination of jack pine forest stands and site conditions will provide researchers and forest managers with a solid overview of how different sites function in terms of productivity, and how they react to disturbance.

Since 1968, Canadian Forest Service researchers from the Great Lakes Forestry Centre have studied nutrient cycling in jack pine, with additional forest ecosystems being studied in similar, complimentary research projects since the late 1970s. In 1993, researchers began an even more ambitious program relating to jack pine, with the initiation of a suite of studies that examine the impacts of specific forest practices on jack pine ecosystems. This resulted from one of Ontario's Environmental Assessment requirements: that the effects of whole-tree harvesting on long-term site productivity be examined in detail. The Ontario Ministry of Natural Resources, at the same time, set up a complimentary study focusing on black spruce ecosystem productivity.

In conclusion...

The Jack pine ecosystem productivity project is a long-term, detailed, and comprehensive examination of the physical, chemical and biological inter-workings of a variety of jack pine sites across north central Ontario. The project is focusing on the effects of various silvicultural disturbances and harvesting practices on site productivity. For forest managers and practitioners, the study is providing a better understanding of how to maintain ecosystem productivity (healthy tree and vegetation growth capacity) in disturbed jack pine sites. The results of this project will greatly assist forest managers in both modifying existing and developing new and potentially innovative harvesting and silvicultural practices that maximize site productivity over multiple rotations.