Stand Initiation

Competition with different life forms

• Herbs• Forbs• Grasses• Woody shrubs

Competition with many species

• “brushy stage”

Wide range of ages

• A small advantage in years can be a large advantage in competitive ability

eastern white pine ( Pinus strobus )

Steven Katovich, USDA Forest Service, Bugwood.org

Wide variation in site

• Small plant size magnifies the growth effects caused by subtle variations in microenvironment– Microsite is the entire environment of the

individual– Trees are in more vulnerable position• e.g. leader frost damage

Stand environment changing rapidly

• Site is still responding to previous disturbance– ‘assart’ effect– Nitrogen fixing herbacious vegetation

Unfilled (available) growing space

• Free to grow stage

Harper sieve• ‘Can’t be old if you die young’– Nature selects for competitive ability during

stand initiation stage– Tree breeding programs do not – require

management