Tuesday, October 30, 2012

Pumpkin Harvest

It seems a bit late to be harvesting pumpkins for Halloween, but the farmers across the road were busy today bringing in their pumpkin harvest. I only mention it because of the curious sounds coming from across the road this fall. I have been hearing what, to my inexperienced ear, sounds like a shotgun coming from the fields of the experimental farm. I don't think it is an actual gun as it happens too regularly each evening and I don't believe guns are allowed inside the greenbelt. My speculation is that there is some sort of noise maker on a timer set up to scare off the geese from the field of pumpkins.

Sunday, October 28, 2012

Ground Crab Spider

Ground Crab Spider(Xysticus luctans?)

I went out for a walk one sunny day last week to see if there were still any insects to photograph about. I found this guy hanging out at the top of a dry grass stalk. It is quite a challenge to identify a small beige spider from the bug guide as not too many amateurs bother to submit photographs of modest little critters like this. This guy however has a bit of yellow on the abdomen and some markings that are quite distinct so I hoped I could make an ID.

The way she held her long fore legs together reminded me of a crab spider so I just browsed through the page after page of crab spiders in the bugguide website hoping to get lucky. I was lucky, someone has already submitted photographs of a spider that has almost identical markings to this guy. It was identified as a Xysticus luctans ground crab spider but as a recent ESC blog entry reminds me, it often takes a specialist and close inspection of the genitalia to properly identify down to the species level. The big problem I have with this ID though is that I found her at the top of the grass spinning some thread. That's not what I expect from a spider called a ground crab spider!

Friday, October 26, 2012

Green Grass and Fall Colours

After four summers the 2009 trees actually have a few leaves this year to contribute to the fall colours. Perhaps in a couple of more years they will be more than just a few blobs of colour in a field of long green grass.

I've been pulling back the grass from the base of the trees again this fall but I haven't seen much evidence of voles. I don't really know if pulling the grass back from the trees is doing any good; perhaps there just aren't as many voles for some reason or perhaps the earth around the tree roots has compacted so much that it isn't a particularly desirable place for voles to make their home anymore( at least compared to the root balls of first year transplants).

I've noticed that the grass this year is easier to pull away from the trees than it has been in previous years. It seems less dense with fewer grass plants per square inch. Where in previous years I could grab so much grass in a handful that it would be physically hard to pull up, this year I can tear a handful out pretty easily. That is unless it is a fescue. A fescue is a course grass with wide rough-edged leaves that forms clumps. I'll invariably pull up a sod of earth if I grab a handful of fescue. I'm not sure which type of fescue it is but it looks pretty much like meadow fescue according to this linked identification guide. The other common grass I'm pulling away from the base of the trees is kentucky bluegrass. I can tell it is a bluegrass from the boat prow shaped tip of the grass blade. Kentucky bluegrass grows quickly in cool weather, and is one of the first grasses to develop seed heads in spring. It has a second growth spurt in the fall long after the seed heads have disappeared. The lush green grass in the above photograph is primarily due to the renewed growth of the bluegrass.

The third most common grass in the field is quack grass. It is a perennial and is forming several large patches. The fourth most common grass in the area also forms patches that persist from year to year. It is an as yet unidentified 7 foot tall perennial grass that looks a bit like a fescue. To round out the list of common grasses I've noticed, Timothy is quite common but doesn't form large clumps. I've also identified some meadow brome and orchard grass growing in the area but they don't seem to be very common.

Sunday, October 14, 2012

Ashes before the invasion

A White Ash (the yellow tree)

I went to a meeting about the Emerald Ash Borer (pdf) last week. It seems like this is the year that this nasty bug went from being a small infestation to a general epidemic for the Ottawa area. It was first found in eastern Ottawa in 2008. There have been predictions that it will wipe out all the ashes but for a few years if you weren't in the affected areas it didn't seem to be spreading very quickly. Now, this fall, the report is that it has spread to all parts of the city including the rural areas. The prediction now is that if you want to save your ash trees you should start giving them the expensive TreeAzin biannual injections next year.

So far the Manordale-CraigHenry area has been lucky but according to this map the first cases have been found in this neighbourhood. Ashes weren't planted along Hunt Club Road in the 2009 to 2011 tree plantings as we knew the ash borers were coming but ashes make up a significant portion of the trees planted in 1995. I went out the other day to inspect a few of the ashes to see if I could find any of those D shaped holes that the adult Emerald Ash Borers bore out in order to escape from the tree. I didn't find any holes but I didn't really expect to as I don't think they have reached here in significant numbers yet. I'll keep a look out next summer for the adults.

The ash trees in the 1995 planting area are about 6inches in diameter and are just starting to get their distinctive deeply furrowed bark. They aren't the largest most vigorous trees and tend to be out-competed for sunlight by the silver maples and the poplars. Some of them have died off already. I inspected under the bark of one of the dead ones but I didn't find any tracks indicating it was a victim of the ash borer. In the above photo you can see the yellow ash tree only gets enough light because it is at the edge of the wood, otherwise, it would be thoroughly dominated by the still green maple tree. I'm not sure that competition is the entire story though, one ash tree in a good open location along the forest edge died two years ago for no apparent reason. That is the one I searched without success for evidence under the bark of the ash borer.

Although the ash trees in the 1995 area are likely goners due to the emerald ash borer's eventual arrival, they have already cast their seeds and there are a multitude of seedlings growing up on the north side of the berm. I am more hopeful of their survival. First, they will hopefully be still too small when the height of the infestation hits the area. Second, I hope the parasitoid wasps will come in time to save the day for these small seedlings. US scientists have introduced three different types of wasps that are the natural predators of the emerald ash borer and that are able to naturally control their population in northern Asia. One of the panelists at last week's meeting said he hoped to see some balance brought back to the EAB population in five to ten years time. That would be too late for today's trees but it gives hope that today's seedlings might still have a chance.

Sunday, October 7, 2012

Under the old oak tree

As you can see in the above picture, the grass grows very poorly under the oak tree. The red oak has created a semi-circle of bare earth where nothing much seems to grow. The problem isn't uniform; it is mostly on the south side of the tree, which also happens to be the downhill side of the tree. Even though this lawn area has full sun for much of the year, moss grows on the bare patches of earth. Most mosses like acidic soil so the tree is most likely somehow making the soil acidic. It is striking that it is only on one side of the tree. The mower prevents leaf litter from accumulating below the tree and what acorn, leaf and twig litter that does fall from the tree should equally impact the lawn on the north side of the tree where the grass looks healthy. Therefore I don't feel it is the organic matter added by the tree that is causing the soil to be acidic.

The bare earth semicircle is most pronounced around the drip line of the tree where the tree roots would be sucking the most moisture from the soil. An alternative theory is that it is a lack of moisture that is preventing the grass from growing on the sunnier side of the tree. A third theory is that the acidity comes from the rain dripping off the leaves and branches and running down the hill. The bare patch close to the trunk might also be explained by this theory since the rain water hitting the west side of the trunk would tend to leach into the soil right where the bare patch is: down-slope from the west side of the base of the trunk. Perhaps both theories are contributing factors and it is a combination of acidity and dryness that prevents the grass from growing on the south side of the tree.

Brown roll-rim (Paxillus involutus)

On the north east side of the oak tree where the grass is greener there is a whole bed of large brown mushrooms poking out of the grass. They grow to about 4-5 inches wide. They initially are paler than in the above photograph and have a pronounced rolled rim. I don't know much about mushrooms but after looking at various guides and searching on the web I'm fairly confident I've correctly identified these mushrooms as the common generalist fungi: Paxillus involutus. This is a deadly mushroom that was considered edible until a German mycologist ate one too many plates of them. It seems that after multiple exposures these mushrooms can trigger an immune response that causes your body to attack its own red blood cells.