Tree species differ sharply in shade tolerance for seedling establishment

Evidence

A certain amount of shade is needed to help most young trees start growing, but too much may prevent their growth. The actual amount may greatly vary. Thus youny lodgepole pines and quaking aspens need practically no shade at all for beginning growth, while hemlocks and most firs in their youth demand considerable shade. Often you may see in the woods a group of young trees that have sprung up where a giant old tree has recently fallen to let down some sunlight, but in many thick, dark forests young trees of most of the species that are growing there may not be able to get a start because of the shade. — Vinson Brown, Reading the Woods, 129

A certain amount of shade is needed to help most young trees start growing, but too much may prevent their growth. The actual amount may greatly vary. Thus youny lodgepole pines and quaking aspens need practically no shade at all for beginning growth, while hemlocks and most firs in their youth demand considerable shade. — Vinson Brown, Reading the Woods, 129

Categorization

• XREF: Connects to the gap-dynamics and disturbance story reading central to the field course. — connects to: Shade competition kills lower branches as crowded young trees grow — Vinson Brown, Reading the Woods: Seeing More in…, 418; Rhododendron understories shift gap regeneration toward species that seed onto logs — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 218; Leaf arrangement in layers sets which light regime favors a tree species — S. T. A. Pickett and P. S. White, eds., The Ecology of Natural Disturbance and…, 1318 (+1 more)
• DEFINE: Distinguishes shade-intolerant pioneers (lodgepole pine, quaking aspen) from shade-demanding species (hemlock, fir) — a key Minnesota forest identification distinction.
• SHARE: A tidbit for a fellow field-course student trying to remember which conifers regenerate under canopy.
• corroborated: 2 independent passages support this claim — Vinson Brown, Reading the Woods: Seeing More in…, 129