Spruce

Spruce are trees of the genus Picea, a genus of about 35 species of coniferous evergreen trees in the family Pinaceae. They live in the northern temperate and taiga regions of the Earth.

Spruce are large trees, from 20 to 60 (–95) m tall when mature, and can be distinguished by their conical form and their needles, that are attached singly to the branches in a spiral fashion. The needles are shed when 4–10 years old.

 Growth 
More than half of spruce seedling mortality occurs during the first growing season and is very high during the first winter.Alexander R.R. 1987. Ecology, silviculture, and management of the Engelmann spruce–subalpine fir type in the central and southern Rocky Mountains. USDA, For. Serv., Washington DC, Agric. Handb. 659. Seedlings get freezing damage, frost heaving and erosion, and smothered by litter and snow-pressed vegetation. 

Losses often remain high for some years. "Establishment" is a subjective concept based on the idea that once a seedling has successfully reached a certain size, not much is likely to prevent its further development.Noble D.L.; Ronco F. 1978. Seedfall and establishment of Engelmann spruce and subalpine fir in clearcut openings in Colorado. USDA, For. Serv., Rocky Mountain For. Range Exp. Sta., Research Paper RM-200. 12 p.

 Classification 
There are 35 species alive in the world. The Plant List has 59 accepted spruce names. The other list is World Flora Online.

 Other websites 
 Arboretum de Villardebelle Picea cone photos Cones of selected species (page 1)
 Arboretum de Villardebelle Picea cone photos Cones of selected species (page 2)
 Gymnosperm Database – Picea

 References 

Category:Conifers