BLACK SPRUCE
Picea mariana (Miller) B.S.P.
Plant Symbol = PIMA
Additional Information
Alternative Names
Bog spruce, swamp spruce, shortleaf black spruce
Description
General: Trees to 25 meters tall (often shrub-like near tree-line), the crown narrowly conic to spire-like or “irregularly subcylindric;” branches short and drooping, frequently layering; twigs not pendent, slender, yellow-brown, hairy; bark gray-brown. Needles evergreen, 0.6-1.5(-2) cm long, 4-angled, stiff and blunt-tipped, waxy and pale blue-green. Seed cones 1.5-2.5(-3.5) cm long, fusiform, purple-brown at maturity; cone scales fan-shaped, broadest near apex, 8-12 mm long, rigid, margin at apex irregularly toothed. Native. The common name refers to the dark (blackish) foliage.
Needles
1/2 inch long, light blue-green, four-angled with whitish lines on all sides;
Blunt-pointed;
Current year twigs with short red or brown hairs.
Cones
1 inch long, rounded and dark;
Scales rigid and brittle, margins rounded to toothed;
Stay on for several years, hang on short stalks.
Bark
Thin, gray to blackish, becoming flaky with age;
Inner bark is yellow.
Size at maturity and life span
15 to 30 feet tall and 3 to 6 inches in diameter, larger in ideal situations;
Can reach 250 years in age.
Habitat and distribution
Wet and cold sites on flats or north-facing slopes, also in bogs;
Usually at lower elevations;
Throughout southcentral and interior Alaska east through Canada to Alaska Ocean, from the northern tree line south to the Great Lakes.
Adaptation
In muskegs, bogs, bottomlands, and relatively dry peatlands; at 0-1500 meters. Black spruce usually grows on wet organic soils but productive stands also grow over deep humus, clays, loams, sands, coarse
till, and shallow soil mantles. It is often a postfire pioneer on both uplands and peatlands. In fire-prone areas, such as upland ridges, fire usually results in the immediate reestablishment and eventual dominance of black spruce, because it produces seed at an early age.
Management
Black spruce grows more slowly than many associated trees and shrubs, and mature trees in spruce-fir stands apparently respond better to release than white spruce and subalpine fir. Many intermediate and suppressed black spruce in swamp stands, however, die after heavy cutting
Clearcutting in strips or patches is generally considered to be the best silvicultural system for managing black spruce. Satisfactory reestablishment after clearcutting requires an adequate seed source and often some kind of site preparation. Uneven-aged or all-aged management is best applied on poor sites where stands are windfirm and have abundant layering.
