Factors of Disturbance


Storms, fires, invasive insects, and unsuitable climate will remove mature forests from the landscape, while other factors, such as deer and European earthworms, will prevent tree reproduction. The loss of mature trees will also contribute to lack of reproduction through reduction in propagule availability. The net result for forests within a few hundred kilometers of the prairie–forest border is that tree mortality will increase and regeneration may not be able to keep pace.

Lee E Frelich and Peter B Reich

Front Ecol Environ 2009; doi:10.1890/080191. p7

The expected net impact of these factors will be a “savannification” of the forest, due to loss of adult trees at a rate faster than that at which they can be replaced. This will cause a greater magnitude and more rapid northeastward shift of the prairie–forest border, as compared with a shift solely attributable to the direct effects of temperature change.

Lee E Frelich* and Peter B Reich

Front Ecol Environ 2009; doi:10.1890/080191

Please visit the Center for Hardwood Ecology at cfhe.cfans.umn.edu/

For information on affected trees,

click on the tree names below:

  1. Balsam Fir, Balsam Poplar, Black Ash, Black Spruce

  2. Jack Pine, Paper Birch, Quaking Aspen, Red Pine, Tamarack, White Spruce

Lee Frelich, Ph.D. has determined that these trees will disappear from the Minnesota Boreal Forest in the following order:

First:  Balsam Fir, White Spruce,

and Balsam Poplar

Second:  Red Pine, Black Spruce,

and Jack Pine

Third:  Quaking Aspen and Tamarack

Fourth:   Paper Birch

Uncertain:Black Ash

Prairie–forest border in central North America (thick black line). Forest cover shown in green, non-forest is white, and water is black. Modified from DeFries et al. (2000).   Lee E Frelich* and Peter B Reich   www.forestry.umn.edu/people/facstaff/frelich/index.html

The definition of boreal from the Free Online Dictionary:
bo·re·al (bôr-l, br-) adj.
1. Of or relating to the north; northern.
2. Of or concerning the north wind.
3. Boreal Of or relating to the forest areas of the northern North Temperate Zone, dominated by coniferous trees such as spruce, fir, and pine.

The boreal forest on the northern edge of Minnesota thrives in the conditions of boreal forests: long, cold, and dry winters with short (50-100 frost-free days), moderately moist, warm summers.  The boreal forest of Minnesota has a wonderful diversity of majestic evergreen and deciduous trees with many understory plants that are dependent on them.