Tree species differ in their tolerance for shade and competition (Table 3-1). Trees often are classified as very tolerant, tolerant, intermediate, intolerant, and very intolerant to shade. Some species tolerate more shade as seedlings than as larger trees. Species that are very tolerant will reproduce and grow in deep shade beneath a dense canopy. Species that are very intolerant will survive only if their seeds sprout in wide openings that receive direct sunlight. The size of canopy openings, ranging from the loss of a single tree to removal of many acres, greatly influences which tree species will reproduce and survive. You must know the shade tolerance of a species to determine the light conditions necessary for reproducing it. Tree species that regenerate in openings may be different from species forming the original canopy, thus changing the species composition over time according to the size of canopy openings created.
|Table 3-1. Tree species by shade tolerance classification.1|
|Very Intolerant||Intolerant||Intermediate||Tolerant||Very Tolerant|