Sunday, April 22, 2012

Balsam Fir

As a youth I was always intrigued by the Balsam Fir Tree [Abies balsamea]. The bark of this tree typically produces blisters containing an oily gum. Back in the 60's we often had to entertain ourselves through bouts of boredom as there was very little in the way of electronic gadgets then. So as kids one of the activities we did was break a small twig, poke one end of it into the gum blister and then place the twig in the water of a stream or ditch. The twig would then be propelled by the change in surface tension on the water which was sort of entertaining and even mystifying. This was admittedly only a brief diversion, since we with short attention spans then probably had to run off and pursue imaginary forest spirits, or play hide-and-go-seek or something.

Our woodlot has a very limited diversity of trees dominated probably by white spruce which was planted in the abandoned fields and white cedar and ash which naturally regenerated everywhere else it seems. To add to the mix I was advised by a colleague woodlot owner that his property is over run by Balsam Fir so I offered to relieve him of some of the seedlings. I since planted 95 Balsam firs from that event.

This spring I have also ordered and planted Balsam firs, Eastern Hemlocks and Red Maples bought from the Ferguson Forest Centre. All three species are virtually nonexistent here.

There is an excellent website that gives pretty detailed information on tree species of Norther Ontario which is:

Some of these northern species are also common here and I cut and pasted a portion of the data on Balsam firs below.
  • Soils mostly acid, though tolerating a wide range of soil acidity, on textures from heavy clay to rocky soils, underlain by a variety of materials, including gneiss, schist, slate, sandstone, and limestone. Most common on cool, medium to wet sites with soil pH of 5.1-6.0.
  • Late successional or climax species. Replaced after fire by pioneering hardwoods and conifers, such as Aspen (Populus tremuloides), Paper Birch (Betula papyrifera), Balsam Poplar (Populus balsamifera), Jack Pine (Pinus banksiana), and Black Spruce (Picea mariana), it is generally absent for the first few postfire decades.
  • Shade tolerant with less demanding seedbed requirements than many associates, it readily establishes under a canopy of hardwoods and conifers. Usually common in understory beneath pines, aspen, and paper birch. In the continued absence of fire, may assume dominance as the canopy of the pioneering trees begins to die off.
  • Subject to windthrow, especially on shallow wet soils.

Saturday, April 21, 2012

Buckthorn Succession - Something New

While attempting to find suitable locations for tree planting, I thought I would plant some shade-tolerate trees like hemlock and balsam fir in areas that are completely overtaken by Glossy buckthorn [Rhamnus Frangula] with the hopes that the trees would in time shade out and out compete the buckthorn. Much to my surprise and delight I already found Eastern white cedars [Thuja occidentalis] growing among the buckthorn as seen in this photo. This cedar is also known to be shade tolerant and appears to be doing well even in the heavy shade of the buckthorn. This is so encouraging. The losing battle with buckthorn can be exasperating at times.

What Exactly is the Name of that Buckthorn?

There are two species of buckthorn on this woodlot. By their Latin names they are Rhamnus frangula and Rhamnus Cathartica. There is ample confusion about their names for me anyway since I tended to use European buckthorn to name one of them and thus the Latin names were very helpful. For that matter, even for R. frangula there is also another Latin name: Frangula alnus, considered by some to more accurately describe the plant. I will stick with R. frangula for this blog's sake. Listed here are some common names used and their origins:

R. cathartica R. frangula
Brief description as I know them on our woodlot. Small thorny tree, purple/brown shiny stem less invasive than R.frangula Thicket with no thorns and gray bark, very invasive here on this woodlot.
Books: Underlined = principle name used b. = buckthorn
Shrubs of Ontario, Soper & Heimburger, Royal Ontario Museum
ISBN 0-88854-283-6
Common b. Glossy b.
Trees in Canada, Farrar
ISBN 1-55041-199-3
European b.
Common b.
Purging b.
Glossy b.
Alder b.
Trees of Ontario, 2001, Kershaw, Lone Pine
ISBN 1-55105-274-1
European b.
Common b.
Purging b.
European waythorn
Hart's thorn
Carolina b.
Glossy b.
European alder-b.
European Alder,
Columnar b.
Fen b.
Black dogwood.
Trees and Shrubs, 1972, Petrides
ISBN 0-395-35370-X
Common b. European b.

Common b.
Purging b.
Alder b. Common b.
European b. Common b.
European b.
Glossy b.
Black b.

In conclusion, it seems that the name that is least confusing or most common in English for Rhamnus Cathartica is Common buckthorn and for Rhamnus frangula is Glossy buckthorn which I will endeavour to use from now on. I was inclined to use European buckthorn which really didn't help my situation as you will see from the list. Both buckthorns are imports from Europe and its adjacent continents so they both can be called European I suppose.

Friday, April 06, 2012

Rock Heaves

Why do rocks work their way up out of the ground? Ten years ago the spot in this picture was level without any visible signs of rocks or dips in the grass. Now there is this huge 200 kg (440 lb) rock emerging a little more each year as shown here. I can't get my riding mower over it anymore as I have in the past.

It turns out that this rock is lifted by ice buildup referred to as an ice lens below the rock. This is typical of a frost heave and apparently these don't occur due to the expansion of water due to freezing as I first thought, but due to the capillary action of water in fine soil that creates these ice lenses and it is brought on by alternating freezing and thawing near the frost edge. This happens in fine porous soil like our glacial till, but does not happen in sand or clay since neither allow capillary action of water. The soil also exerts pressure on the sides of the rock which by friction will hold up the rock. As the ice underneath melts and drains away it leaves an empty void and soil likely erodes and trickles in to partially fill this void from the sides before the rock settles back down although a little higher than the original position. 

What is interesting in this picture is the sink hole to the right of the rock that is about the same size in volume as the amount of rock protruding above the soil, so this soil is evidently creeping down under the rock over time. 

Extracting such a large rock out of the ground is a lot of work. Instead, one might let nature do the work over a longer time. One can fill the depression and build up earth around the rock to keep it lifting and just mow around it. At some point the rock will be lifted so high that all one has to do is remove the surrounding earth and take the rock away more easily. In the mean time it can be a conversation piece in the lull of a party and squirrels can use it as perch while nibbling on pine cones.  This is living with nature I figure.