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It has been a busy few weeks for me — holiday traveling, Green Expo talks (that’s our regional conference), and getting ready for a semester leave this year — I’ll be working on a project investigating how professors transfer information to the public.  But during this time I have, for some unexplainable reason, been thinking about Canadian Thistle.  And do you know what I’ve come up with?  This: 

It’s a colossal waste of time and money to worry about Canadian thistle. 

Despite its name Canadian thistle is not native to North America.  It was introduced in the 1600s — probably by accident.  Most parts of the plant are edible and some people even say that it’s tasty.   Though it can be found across the US it is rarely found in such high concentrations that it displaces native species.  Where it does dominate the landscape conditions are usually bad enough (highly disturbed sites) that other plants won’t fare well anyway.  Canadian thistle is known as an early succession plant which means that it will establish in a disturbed site — perhaps even taking it over — but will slowly, over years, be taken over by other plants.

Canadian thistle is considered a noxious weed across the United States, but it is classified that way mostly because of political pressure rather that for what it does (if nothing else it is a very visible, nasty looking plant).  People may get scratched up, but you won’t hear about anyone dying from Canadian thistle poisoning.  As an agricultural weed it can be significant, but usually pales in comparison to other weeds.  Because it is listed as a noxious weed some states and local governments have tried to rein it in, at least over small areas, but this thistle is very resistant to herbicides, and tough to kill just by pulling, and so efforts are often fruitless. 

Should we redouble our efforts and assail this thistle with more energy?  I just can’t bring myself to say yes.  This weed may be undesirable, but to put much money into a losing battle with a weed that has been here for about 400 years and that mostly affects disturbed sites seems like a silly strategy.  In my mind we should be treating this weed as undesirable, but not nearly at the same level as other invasive or noxious plants.</d

NOTE: Linda and I switched places this week so we could get the Garden Professors survey up on Monday – See Linda’s post for the link – please take a minute to give us your feedback!

I recently received a copy of a newsletter from the USDA Forest Service Pacific Northwest Research Station that included a summary of an article recently co-authored by one of the Station’s scientists on the effect of urban tree cover on pregnancy outcomes of new mothers in Portland, OR http://www.fs.fed.us/pnw/sciencef/scifi137.pdf

According to the summary, researcher Geoffrey Donovan and his colleagues found that babies born to pregnant mothers who lived in neighborhoods with high amounts of tree cover were more likely to have higher birth weights than babies born to mothers living in areas with less tree cover.  Of course, being a skeptical (cynical?) Garden Professor my first reaction was, “Well, duh…expectant mothers that live in areas with more tree cover are probably living in better neighborhoods, are wealthier, better educated, and have lots of other things going for them that we typically associate with better pregnancy outcomes.” 

The summary put out in the PNW Station newsletter was scant on these details so I went on-line and dug out the original paper (citation below).  As I suspected the authors noted that, “Women with greater access to urban trees were more likely to be non-Hispanic white, younger, have fewer previous births, and live in newer, more expensive houses closer to private open space compared to women with less access to urban trees.”  However, they were able to account for these effects in their statistical analysis and still found that birth weight increased with the amount of tree cover near the mothers’ homes.

As we’ve all heard many times, correlation is not causation and it is unclear exactly how tree cover improves pregnancy outcomes.  One of the most likely explanations for the tree cover effect is that having more trees around reduces stress levels, resulting in better birth outcomes.  Trees can also reduce noise and other forms of pollution as well.  Regardless of the mechanism, this study may provide one more bit of ammunition for urban forestry advocates that go to battle for trees in our cities.

Donovan, G.H.; Michael, Y.L.; Butry, D.T.;Sullivan, A.D.; Chase, J.M. 2011. Urban trees and the risk of poor birth outcomes. Health & Place. 17(1): 390–393.

PS: Don’t forget to take our survey!

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I am a last minute shopper.  There, I admitted it, and I’m proud of it.  By waiting until the last minute I get to hear about everyone else’s great gifts — and then buy those same gifts for someone else!  that said, here’s a short list of gifts for gardeners — including a few that I wouldn’t mind having myself.

#1  Books — they’re great, especially in the off-season when the gardener in your life needs some inspiration.  Naturally books by a garden professor is preferred, but I also love anything by Lee Reich.  Another one of my new favorites is the book Taming the Truffle.  For something different try The Foragers Harvest by Samuel Thayer.

#2 Pruners — You can NEVER have enough pruners.  There are many nice pruners out there, but the standard by which all others are measured are the Felco #2s.

#3 Gloves — you can never have too many gloves!  I prefer leather — most gardeners have their personal preferences.

#4 Weird seeds.  OK, it’s a little late to be searching high and low — but most gardeners really love to try new things — so go and get ’em something totally off the wall.  Something beyond tomatoes, cucumbers, squash and watermelons (peanuts maybe).  See if you can find Pawpaw!

#5  A renewable organic fertilizer — not guano or rock phosphate.  Something like cotton seed meal.  Manure is probably a no-no though.  Who wants poo in their stockings?

#6  Moisture sensors of all different types can be fun to play with.

#7  Some fun houseplants — Amaryllis is always a winner – even for non-gardeners!  For the more adventurous look to carnivorous plants like butterwort or even a venus flytrap.

Happy Holidays Everyone!

One thing I’ve always enjoyed about living in Michigan is that we are virtually guaranteed to have a white Christmas each year.  This is in stark contrast to western Washington where I grew up where a white Christmas was a relatively rare event.  In fact, to make the locals feel better, one of the popular songs on the radio play lists during the holidays is “Christmas in the Northwest is a gift God wrapped in green.”  Actually, He usually wraps it in grey fog or drizzle but hey, it’s a nice sentiment.

And for the Great Lakes region and much of the eastern US, a white Christmas may not turn out to be such a sure thing after all.  Snowfall in the East is way off compared to last year.  According to data from National Operational Hydrologic Remote Sensing Center http://www.nohrsc.noaa.gov/nsa/index.html?region=Northern_Great_Lakes&year=2011&month=12&day=14&units=e , only about one-third (33.7%) of the Great Lakes region had snow cover as of last week and the average depth was only 0.9”.

This is quite a difference from a year ago in mid-December when 99.7% of the Great Lakes region was covered with an average of 9” of snow.

Of course, this is Michigan and things can change in hurry.  But right now the forecast for the next couple days is for temps in the upper-30’s and low 40’s.  There’s a chance of snow showers on Saturday so we’ll keep our fingers crossed and hang our hats on a Christmas eve snow for our White Christmas.

May your days be merry and bright, and may all your Christmases be white!

Okay, I’m biased:  I’m a whole plant physiologist, meaning that I like to study entire plants in their environment, not just their cells or DNA in a lab.  I got hooked on plants as an undergraduate in marine biology when I took plant physiology for “fun” (translated: I couldn’t find another biology elective to fill the time slot).  Discovering why vines curl around fenceposts (thigmotropism) or how plants sense gravity (statoliths) or why bilaterally symmetrical flowers evolved (to accomodate pollinators) was fascinating, and I finally succumbed to the green side when I entered my PhD program.

The book I used as a student was Salisbury & Ross’s Plant Physiology.  There were other texts out there, but this was my bible and I used newer editions when I began to teach Plant Physiology.  Recently (as some of you know) I’ve begun to write a garden book on how plants work.  Plant physiology, of course, is the underlying science, and I needed a new text for fact checking.

Salisbury and Ross, sadly, has not been updated since 1991, so I went with Taiz and Zeiger (which has also been around a long time).  It was a shock for me to discover that plant physiology has somehow morphed into plant molecular biology.  The books is full of gene acronyms and regulatory pathways…but very little of what fascinated me as a student.

Science has been on the reductionist pathway for a long time, and there’s no denying that understanding how genes are regulated is important.  But except for the fields of human and veterinary medicine, we’re losing our understanding of how organisms work.  Faculty experts who specialized in studying algae or mosses or grasses or trees for the sole purpose of increasing our understanding of these species have been replaced with those whose research programs can generate big dollars for cash-strapped universities.  The void left by academia’s abandonment of practical plant science is quickly filled with pseudoscience and mysticism, particularly in alternative agriculture.

All I can say is that if I had been confronted with the 2010 Taiz and Zeiger text as an undergraduate I would have a PhD in marine biology instead.

Last Christmas tree post for me this year and, sadly, it’s not a pleasant one.  As reported by that beacon of journalistic integrity, FOX news, right-wing bloggers killed a marketing check-off program that US Christmas tree producers had worked years to enact.

 http://www.foxnews.com/politics/2011/11/09/merry-christmas-agriculture-department-imposes-christmas-tree-tax/

 

For those that are not familiar, a check-off program or agriculture marketing order is an assessment that a commodity group levies against itself to raise money for marketing and research.  Common examples of marketing campaigns associated with check-off programs are “Pork – the other white meat”, “Beef – it’s what’s for dinner”, “the incredible edible egg”, and “Got milk?”  In the case of the Christmas tree check-off, growers voted to assess themselves a 15-cent fee for each tree harvested to go into fund to support a marketing campaign and research.  A majority of US growers felt the program was a good idea in order to promote their product against foreign-produced artificial trees.  The USDA gets involved in these programs essentially as a neutral third party to help collect the fees and oversee the operation of the marketing board, which is made up of growers and grower-elected representatives.  If the growers didn’t like how the program was working out, they had the option to kill the check-off after three years.

 

All sounds pretty reasonable and rational, right?  It did until right-wing blogger David Addington stumbled up the marketing order in the Federal Register and dubbed it “Obama’s Christmas tree tax”.  http://blog.heritage.org/2011/11/08/obama-couldnt-wait-his-new-christmas-tree-tax/   Once ‘Obama’ and ‘tax’ hit the blogosphere you might as well cue up Don Meredith signing ‘Turn out the lights, the party’s over.’  Just in time for the holiday news cycle, media outlets all over the country pounced on the story.

 

The ironies are to numerous to mention all of them, but here are just a few.  I attended a regional meeting of growers when the check-off was being debated.  Except for the university scientists and extension observers on-hand, the number of people in the room that voted for Obama in the last election was roughly zero.  Moreover, it was the US growers themselves, not Obama or the USDA that pushed for the check-off.  To the best my knowledge, both the President and the USDA have enough on their plates already without sitting around thinking “You know, announcing a tax on Christmas trees right before Christmas would be a good idea”.

 

While ironies abound, so do disappointments.  The administration, with little to gain except a lot of negative and misinformed press, quickly washed its hands of the proposal.  This means the US producers; many of whom had invested years developing and championing the marketing program to stave off competition from China, are left back at square one.  In fact, after the traction given to the right-wing portrayal of their self-assessment as ‘Obama’s tax’, US growers are now a couple steps behind square one.  And it’s doubtful they’ll be able to get back to the start line any time soon.

If you’re getting sick of the compost tea debate then you can skip this post.  If not, then read on! 

This past week I received my copy of Arboriculture and Urban Forestry 37(6).  And in it, page 269, I discovered an article titled “Laboratory Assays on the Effects of Aerated Compost Tea and Fertilization on Biochemical Properties and Denitrification in a Silt Loam and Bt Clay Loam Soils” by Bryant Scharenbroch, William Treaurer, Michelle Catania and Vincent Brand.  Basically what the authors did was to add dilute compost tea, concentrated compost tea, and a fertilizer to a couple of different types of soil in a laboratory setting to establish how they changed the soil.  To be honest the article was a little tough to read for a non-soil scientist and I found myself looking up terms quite often.  Still, I found their conclusions fascinating.  There were actually a number of conclusions, I’m just going to cover what I think are the most interesting:

1. “Aerated Compost tea appears INFERIOR  [you read that right – inferior] compared to fertilizer in its ability to increase microbial biomass, microbial activity” and a few other things.   Hmmm…I’d been told that microbes hated synthetic fertilizer.  I guess not all microbes agree.  In terms of the fertilizer used, it was a 30-10-7.  I didn’t see it explicitly stated in the article, but I’d bet it was a synthetic fertilizer called Arbor Green Pro.  It was applied at what I would consider a heavy dose.
2. Aerated compost tea, or at least the compost tea tested in this article, did contain a significant amount of nutrients.
3. On the up side for compost tea it was pointed out that compost tea treatments might help a poor soil retain more nitrogen.  Maybe…but the authors also pointed out that “only the fertilizer treatment appeared to deliver enough available nitrogen to potentially meet tree needs in the Bt horizon soils” (in other words poorer soils).  Interesting – but if we just added compost we’d have a better soil anyway, which brings us to the next point….
4. The compost tea tested contained only a small portion of the microorganisms that compost does.

So what’s the take home message from this article?  This wasn’t explicitly stated in the article — in fact I’m not even sure the authors would agree with me — but to me the important message is 1) ADD COMPOST and 2) IF YOU NEED TO ADD NUTRIENTS ADD FERTILIZER NOT COMPOST TEA (though I’d go with a nice renewable organic rather than a synthetic).   

I just can’t resist telling our Christmas tree hunting tradition.

On the Friday after Thanksgiving, we drive out to Monroe (about 45 minutes north of Seattle) to our favorite tree farm, where we look for the perfect noble fir.  Here, Jim demonstrates his dubious taste in trees:

This year, Charlotte brought a tennis buddy home from college. Nasko lives in Bulgaria and wasn’t traveling home for a holiday they don’t celebrate.  So he got to experience the Great Scott Tree hunt for himself:

My son Jack (on the left) complained that he NEVER got to choose the tree (Mom retains veto power over all selections), and happily for all of us this year he picked the winner:

Jim does the cutting, and the kids do the carrying:

This tree farm also has hot chocolate and candy canes, which we all enjoy before returning to town (Monroe that is) and having lunch at the local Taco Bell. It’s a tradition that started when the kids were littler and you don’t mess with tradition.

Needless to say, we will ALWAYS have a real tree.

My post on Christmas tree safety got blog readers Michael and Thad into the never-ending debate of what’s better for the environment: a real Christmas tree or a fake one.  As is often said: “Where you stand depends on where you sit.”  In the interests of full disclosure I will admit my bias is on the real tree side.  My first job in high school was shearing Christmas trees back when minimum wage was $1.65 /hour (1976).  Also in the interest of full disclosure I work closely with the Christmas tree growers in Michigan and elsewhere and get a small amount of research support from the state grower’s association.  

Michael and Thad’s discussion turned pretty quickly to the bottom-line when it comes to carbon footprint.  Which choice looks better depends on the assumptions you are willing to make.  The critical ones, of course, are how long do you keep a fake tree and how far do you drive to get a real tree.  If you buy one artificial tree and keep it 50 years it replaces 50 real trees.  If you buy a real tree from a tree lot that’s on you way home and don’t make a special tree to get it, the real tree comes out looking good.  The American Christmas Tree Associate (a trade association for artificial trees, NOT a growers’ group) has commissioned a life cycle assessment and claim the carbon footprint question is a wash  http://www.christmastreeassociation.org/Article%20Pages/choosing-an-artificial-or-real-christmas-tree   This is in contrast to some earlier claims they had made the artificial trees were greener – based largely on the distance driven to get a real tree.

One thing to note is that there are other environmental impacts besides carbon emissions to consider.  Artificial trees are typically made from non-biodegradable plastics and most Christmas tree plantations require some pesticide and fertilizer inputs to keep trees looking good.  In many parts of the country Christmas tree plantation can provide habitat for certain types of wildlife, especially birds that use the trees for perches and nesting.  

Hannah and I embark on Tree-hunt 2011…

While everything seems to get boiled down to carbon comparison these days there are certainly more things to consider.  For those that buy a tree at a local ‘choose and cut’ farm, there is certainly the satisfaction that at least some of your holiday purchases are supporting the local economy.  At the end of the day, however, the debate between real vs. fake for most people gets down to one of two factors: tradition and convenience.  Even though my heart is on the real tree side, I can’t deny that pulling an artificial tree out of a box from the attic each year is easier than going out on a cold wet, December day and getting a tree from a farm and then bringing it home and setting it up.  But my mom was German and we always had a real tree in the house when I grew up.  Now that I have my own family, my daughter and I have a tradition of going out to a local Choose and cut tree farm and looking for the perfect Fraser fir.  No artificial tree can ever replace that. 

Fraser firs at Daisy Hill farm.  Still got a couple years to go, but eventually I’ll be cutting my own.

Over the years I’ve gotten a lot of questions about how to compost.  I’m not a composting expert, and don’t want to pass myself off as one, but I do understand the basics and I like to think of myself as a proponent of composting.  Having said that, there is a composting practice which I’m asked about frequently that I never know quite how to answer.  Should you put meat into your compost?

The easy answer to the question of whether meat belongs in compost is that it is an organic material which will break down just fine along with all of the vegetable matter in your compost.  But there’s more to it than that.  I’ve been to some areas that specifically forbid meat in compost because of the vermin that it will attract.  And it’s true, at least to some extent, that meat attracts vermin.  Rats, raccoons, and other mammals will go after meats.  It’s the high protein content.  How can they resist?  While leaves and grass can have as much as 4% nitrogen, meats will typically have between 5 and even as high as 16% nitrogen.  Of course they go for it! 

Besides the vermin issue, if raw meat is placed in a compost pile it tends to stink, especially if it isn’t mixed into the pile.  Cooked meat (table scraps) breaks down a little bit more slowly than raw meat and doesn’t stink as much.  Because of the high nitrogen content of meat it will get a compost pile to compost a little bit faster.  Personally, I’m in favor of using meat in compost piles as long as you’re careful to turn the pile frequently to keep it inside the pile where it can’t do as much harm.  If you’re a casual composter then you might want to avoid using meat because of the potential problems.  So there it is – in my mind the answer to whether you should put meat in compost or not comes down to how closely you like to monitor your pile, whether there are laws against it in your area, and also the likelihood of mammals getting into it where you live.  Also, at most meat should be a small component of a compost pile — not the main component.