Red spruce reproduces exclusively by seed. The first cone crop is usually produced when the crown first reaches direct light [27,39]. Therefore, red spruce can bear cones as early as 15 to 20 years of age; cone production peaks about 15 years later. In dense, even-aged stands, full cone crops are rare until the trees are 40 to 50 years old . Good seed crops are produced every 3 to 8 years, with light crops in intervening years. Cones are dropped shortly after they are mature . The seeds are wind or rain disseminated. The maximuim distance for dispersal by wind is approximately 201 feet (61 m) . Seeds do not exhibit dormancy. Most germinate the spring following dispersal; occasionally germination will occur in the fall soon after seeds drop from the tree. Seeds are usually not viable after 1 year. Germination is largely controlled by moisture availability. Seeds will germinate in almost any medium except sod. Seeds that germinate in thick duff are subject to overheating and/or drought mortality. Drought and frost-heave are the major causes of seedling mortality the first year . Successful reproduction appears to depend more on seedling survival than on germination requirements . Seedling establishment is usually best on shallow, less fertile soils that discourage competitive hardwoods . The primary roots of red spruce seedlings do not penetrate litter and forest duff to any depth . Red spruce seedlings have a root system of finely branched rootlets and no strong laterals; they depend entirely on the humus for nutrients and water .