Earth Partnership for Schools


WOODLAND PLANT COMMUNITY - NORTHERN DRY FOREST (JACK PINE FOREST)

General: Fires are relatively frequent in northern dry forests. On the average this forest burns every 125 to 180 years. Jack pine, a dominant tree in the community, evolved a reproductive strategy that depends on fire for survival. The tightly closed pine cones require temperatures of at least 116° F (46.5°C) to soften the resin, open the scales and release the seeds. Cones will remain on the trees for 25 years before falling to the ground. Jack pine is a pioneer tree, intolerant of shade. It colonizes bare areas and will survive only one generation without fire.

Topography: Jack pine forests often grow on uplands, rolling sandy plains, sand dunes, steep rocky land, and shallow soils over rock outcrops.

Microclimate: Excessive water drainage and low storage capacity of the soil create droughty growing conditions. The open canopy allows sunshine through to the forest floor, which increases evaporation and aridity. As the forest matures, the general moisture and humidity increases.

Composition: Species listed below are most likely found in the community.

Dominant Trees: Jack pine, red pine, and white pine.

Common Trees: Hill's Oak, trembling aspen, and large-tooth aspen.

Typical Shrubs: Hazelnut, lowbush blueberry, and dwarf bush honeysuckle.

Prevalent Groundlayer: Canada mayflower, bracken fern, and false Solomon's seal. Herbs and shrubs with evergreen leaves, such as pipsissewa, trailing arbutus, and wintergreen are common. Nearly an equal number of groundlayer species will bloom in spring and summer. A few bloom in the fall, such as largeleaf aster and northern heart-leaved aster.

Structure: A young forest is often dense with numerous even-aged trees and shrubs due to disturbances such as fire or wind throws. As the forest matures, the pines lose their lower limbs creating a light, park-like forest. Bunchberry, club moss, and Canada mayflower will form dense carpets under the canopy of trees. Forests dominated by Jack pine may have up to 308 trees per acre.

Stability: Unstable—a one-generation forest in absence of fire. Succeeded by northern dry-mesic or mesic forest.

Soil: Sandy or gravelly soils. Well to excessively well drained.

Major Soil Series: Vilas, Omega, Boone, Plainfield, and Coloma.

 

Summary of Soil Analysis:

W.R.C.

120%

p H

4.9

Ca

1255 p.p.m.

K

94 p.p.m.

P

? p.p.m.

NH4

? p.p.m.

Typical Number of Species: Trees 25, Shrubs 57, Herbs 182, Total 264
Species Density: 39
Guild SE ES LS SV WA WG DI MY EV
Average Proportion 0% 35% 22% 25% 0% 0% 0% 2% 17%
Guild Key: SE = Spring Ephemeral; ES = Early Summer; LS = Late Summer;
SV = Shrub/Vine; WA = Winter Annual; WG = Wintergreen; DI = Dimorphic; MY = Mycotrophic; EV = Evergreen
Wildlife: Towhee, rose-breasted grosbeak, woodpecker, great horned owl, gray squirrel, black bear.
Typical Examples: Castle Mound S.A., Cox Hollow S.A., and Necedah S.A.
Geographical Distribution: S. Manitoba, N. Minnesota, N. Wisconsin, N. Michigan, S. Ontario, N. New York, and New England.