Canadian Shield forests and forest regeneration   srgale-@comcast.net
  Mar 19, 2006 09:55 PST 

Firstly, I’d like thanks the ENTS members who have read/replied to my
posts; it’s nice for a new poster to feel welcome on a message board.
I’ve been looking throughout the ENTS site, at old threads, photos,
measuring guides, etc.---[I wish a site like this existed back in the
days I studied botany at Miami U., but, well, the Internet didn’t even
exist then, so I guess that really is wishful thinking.]


This is a Google Earth http://earth.google.com image that shows the areas 
quite clearly. The deep green areas to the left are the more mature woods,
the bright green/tan area to the right is the burned area, and the
brownish areas are the jack pine colonies. http://usera.imagecave.com/srgalehouse/IslandLakeGoogleimage.jpg

I’d like to share some information and observations about forests and
forest regeneration on the Canadian Shield; I couldn’t find much mention
of this in the archived articles on the ENTS site, and some of you might
be interested, so here goes.

I’ve been visiting an area of central Ontario, around 60 mi. west of
Algonquin P. P., on a yearly basis for the past 40 years. The area has
recently become protected as a “conservation reserve”, with any
logging/mining/development prohibited. The area is only accessible via
floatplane or by canoeing with portages, or by snow machine in winter.
The area is typical Shield country with numerous lakes, marshes, exposed
granite, and shallow soils in depressions. The entire area was logged,
perhaps 120-100 years ago, and the eastern portion of the area
experienced a major burn, perhaps 80 years ago.

The current species makeup seems to be a combination of northern
hardwood and boreal species, including: white, red, and jack pine, white
and black spruce, hemlock, balsam fir, tamarack, white cedar, sugar and
red maple, with mountain maple and moosewood in the understory, black,
fire, and choke cherry, paper and yellow birch, bigtooth and quaking
aspen along with balsam poplar, and infrequently red oak, beech,
hop-hornbeam, and black ash, and basswood. Cephalanthus is near its
northernmost range here, and Rhexia virginica is near its westernmost
range. Fauna include black bear, moose, eastern timber wolf, and the
area is also one of the northernmost stations for five-lined skink.

The difference between the area that burned and the area that escaped
the burn is striking. The unburned area in the western portion of the
region supports, near the lakes, a “mature looking” forest of primarily
red and white pine, with canopy height of around 70’-80’, based on
measuring fallen individuals. Typical diameters for the older red pines
are 12”-20”, for the white pines 18”-24”. Occasional white pines are
36” or greater in diameter, and in the110’-120’ range. I presume these
were trees that escaped the early logging effort. There are groves of
hemlock with diameters of 20”-24” and 90’-100’ tall that also likely
escaped the logging effort. The largest hardwoods are balsam poplar,
with diameters of 24” or more and a canopy height of around 80’-90’.
These are primarily found inland from the lakes. Occasionally sugar and
red maple and paper and yellow birch will also achieve a large size,
over 24” in diameter, but red oak is conspicuously small and scrubby.
The understory in the unburned area mainly consists of the shrubby
maples, Corylus, Viburnum alnifolium, suppressed red and sugar maples,
bunchberry, and ericaceous sub-shrubs. The overall aspect is that of a
cool, moist woodland with a high canopy. Large swaths of even-aged jack
pine (and pretty much nothing else) are also found surrounded by this
mature looking forest. The jack pine is very uniform in size and
height, usually 6”-10” in diameter and 50’-60’ tall. I think these jack
pine areas must represent burns that occurred prior to the general
logging of the area, since there are generally no cut-stumps among the
jack pine.

The burned area is entirely different. This area is very much “open”,
with occasional groves of aspen, predominantly bigtooth, that achieve a
height of 60’-80’, occasional paper birches as individual or small
groves, open grown low-branched white pines, and scrubby red maples
often multi-stemmed due to deer rubs. Much of the area is covered by
low to medium size shrubs, especially fire and pin cherries, staghorn
sumac, Amelanchier alnifolia, Aronia melanocarpa, common juniper in its
recumbent form, low-bush blueberry, Rubus spp., and fruticose lichens.
The aspect is almost arid, and on a sunny day the temperatures are
easily 15-20 degrees greater than in the unburned area.

The surprising thing, to me, is how very little the burned area has
changed compared with 40 years ago. There has been very little
arborescent growth in an area than once held good-sized trees (based on
charred stumps that can still be found). Observing old-field succession
here in Ohio, I would have expected much more forest regeneration than
has occurred. I have to guess the fire of 80 or so years ago was so
intense as to also burn much of the organic material in the shallow
soil, and that this has contributed to the slow recovery.

I created a "hobby" website relating to the area I
mentioned in the Canadian Shield post, although the stress of it isn't
concerning the forest. A link to it is: http://www.newcamp.org 

Steve Galehouse

Re: Canadian Shield forests and forest regeneration   Lee E. Frelich
  Mar 20, 2006 08:21 PST 
Steve:

There was a session devoted to alternate states created by forest fires at
the ESA meeting in Montreal. Several people from the University of Laval,
and University of Quebec at Montreal were there and explained that some
sites take many centuries to recover after fire, whereas others recover to
forest within a few years. We see the same thing in northern MN. Sites
that are logged and then burned as especially likely to convert to an
alternate state after the fire, since harvesting removes more nutrients and
removes certain seed trees that usually survive fires.

Lee