Hello Students!   Many of you are learning about seasons and participating in the GLOBE Green Down Seasons Protocols.  I thought that it would be fun to do my own seasons study!   On this page I am going to share with you everything about my green down study.  Please feel free to make comments and ask questions!  If you see how I could improve my study, please let me know that too!!   I am going to study green down (the fall change in the color of a plants leaves) of the silver maple tree in my back yard.  I have lots of questions about green down.  Here are a few:   When will my maple tree begin green down? When will green down end? Will the leaves fall off the branches before snow covers them? Does my maple tree begin green down on the same day every year? If it does, how does the tree 'know' what day it is? If it doesn't, what factors cause green down to happen earlier or later in the year? Does El Nino affect green down? What causes green down?

Oh gosh!  I have SO many questions! Many of my questions could be answered by searching the internet, reading books, or interviewing scientists.  I bet I can write to a GLOBE scientist and find out if El Nino has an affect on green down.  And I can probably find a website or book that will explain what green down is and what causes it.  Some of the other questions require me to collect data.  If I collect green down data beginning today, I will be able to learn what day green down begins on and what day green down ends on for my maple tree.  One of my questions will make a really good science project: Does my maple tree begin green down on the same day every year? Or at least it would make a good science project IF I could collect data for more than one year.  So to begin with I am going to do a descriptive study.  I will collect green down data about my maple tree to learn when green down begins and ends this year.  That will allow me to gain a better understanding of what green down is.  I will also be collecting data I can use next year if I want to answer some of my more complete questions.  Since I have never collected green down data before, who knows what observations I will make that will lead me to new questions and new studies and experiments!

DAY ONE - On Sunday, Sept 9th, 2007 I began my study.  I went to the GLOBE Program website and printed off the data sheets to define a Green Up/Down study site and to collect data.  I went outside with my GPS Unit, my data sheets, and my color chart.  I leaned up against my tree and used the GPS Unit to find the latitude and longitude of the tree.  This will let other scientists know where my data was collected.  Why is that important?  Well remember all of the questions I have about green down?  Other scientists have questions about green down too.  My data might help another scientist answer one of her questions.  But for my data to be useful, other scientists need to know how I collected my data (I follow the protocols (rules) from GLOBE) and where I collected my data.  While I was waiting for the GPS unit to warm up, I wrote down some notes about the area around the tree.  I described the buildings and other trees near by.  Next I used a yellow ribbon to label the branch I am using to collect my data.  Then I used the color chart to identify the color of the 4 leaves at the end of that branch.  I wrote my observations and data down on the data sheets.  Then I put the sheets in my backpack to take to work on Monday!

DAY TWO - On Monday, Sept. 10th, 2007 I logged into the GLOBE website to enter my first day's data.  I defined my study site as "Backyard Maple" and I entered the data for the leaf colors for the first day.  Here are the colors of the 4 leaves on the first day:

Leaf 1	Leaf 2	Leaf 3	Leaf 4

One thing I noticed as I was collecting data is that it can be hard to decide which color the leaf is closer to!  Leaf number 1 was lighter in color than any of the other leaves, but it wasn't really quiet as light as the next lightest color on the chart.  So I just did the best I could.  I'm supposed to collect green down data at least 2 times a week.  So I will try to collect my data again on Wednesday.

DAY FOUR - (Sept. 12th) I collected the color data again today and all 4 leaves are the same color as last time.  So I will report that information to GLOBE.  I'm going to try to collect the color data again on Friday or Saturday.

DAY SEVEN - (Sept. 15th) All four leaves are still the same color.  This is good.  It means that I began my data collection before the leaves started to change so by the time winter comes I will have a record of the entire color change from summer to winter! 

DAY TEN - (Sept. 18th) All four leaves are still the same color.  Some other leaves on the tree look a little more yellow to me.

DAY TWELVE - (Sept. 20th)  All four leaves are STILL the same color!  But the leaves at the top of the tree are definately more yellow now.  I'll take a photo of the tree over the weekend and post it on Monday

Day 15 (Sept. 23rd) - Cool!  The leaves are finally changing.  All four are now the same color of green.  They all have a very few lighter green or yellowish blotches too.  The blotches are small and do not cover more than about 5% of the leaf surface.  The table below shows the colors of my leaves today.

Leaf 1	Leaf 2	Leaf 3	Leaf 4

(Sept. 25th) The leaves are all the same color today as they were on Sunday.  The yard has many fallen leaves from higher up on the tree.  The fallen leaves are mostly a yellowish color.  There are not enough to cover the ground. 

Day 19 (Sept 27th) The leaves are all the same color today as they were on Sunday.  More leaves have fallen but not enough to cover the ground. 

Day 21 (Sept 29th)  I am beginning to understand why the scientists only ask for data 2 times a week.  I have been collecting data about 3 times a week, but the leaves don't really change quickly.  When I am not looking so closely, it seems like the leaves change color and fall off the trees so fast.  But now that I am paying attention, I see it does take weeks.  At least it does for the Silver Maples in my back yard.  As you may have guessed, I looked today and the leaves are all still the same color.

Day 23 (October 1) Oh!! Wow!  Something new!  The leaves are still mostly the same green color.  However, the veins on leaves #1, #3 and #4 have all started to turn red!  When I looked at the leaves which had fallen on the ground, I didn't notice this at all, because most of the leaves had turned yellow.  Tonight I will take photos of one of my leaves and a leaf on the ground and post them up here for you to see.

Day 24 (October 2) I took some photos showing leaves with veins that have not changed to red and my study leaves which have.  I took a closer look at the leaves on the ground.  Do the fallen yellow leaves have red veins?  Look here to find out. 

Day  27 (October 5) The leaves all look the same.

Day 31 (October 9th) Again!  They all look basically the same.  I think the red in the veins is a bit darker. 

Day 35 (October 13) Still the same.

Day 38 (October 16) Still the same.  Will these leaves ever change color!

Day 41 (October 19) I guess not!  Still the same. 

Day 45 (October 23) Still the same.  The veins seem to be getting a bit deeper red.

Day 48 (October 26) Still the same color over all.  The veins are definately a deeper red.

Day 52 (October 30) Still the same color.  Lots more leaves are falling to the ground now.  Maybe these leaves will change soon!

Day 54 (November 1) Still the same color.  The top of the tree is almost all done changing color and almost all the leaves have fallen.  The bottom half is about half changed.

Day 59 (November 6) Still the same. 

Day 61 (November 8) Still the same.

Day 66 (November 13) Wow!!!!  What a different a couple days can make.  My leaves have finally changed!  Leaf #1 is still 5GY 4/8, Leaf #2 is now 5 GY 5/10, Leaf #3 is now also 5 GY 5/10 and Leaf #4 is now 2.5 Y 6/6.  Leaf #4 is definately the one that has changed the most.  Here is a table of the new colors:

Leaf 1	Leaf 2	Leaf 3	Leaf 4

Day 67 (November 15) It was so windy last night that I was sure that some of the leaves would be gone.  They are all still there.  Leaf 2 has become yellow but otherwise they are the same as Tuesday. 

Leaf 1	Leaf 2	Leaf 3	Leaf 4

Day 72 (November 20) Another leaf turned yellow.

Leaf 1	Leaf 2	Leaf 3	Leaf 4

Day 74 (November 22) It snowed last night and early this morning.  It was cold enough that the snow stuck to the ground and to my leaves.  However, it was gone from my leaves by the time I took my measurements.  Two of yellow leaves are all still the same color of yellow, but the green leaf has turned a little lighter and a small part of it is even yellow.  And 1 leaf is gone!

	Gone!
Leaf 1	Leaf 2	Leaf 3	Leaf 4

 Day 79 (November 27) All of the leaves are gone now. So what did I learn from this experiement?  Remember all of my questions from the beginning of my project?  Some were questions that require looking in books or asking other scientists.  But some of my questions can be answered, or partially answered through my experiment.

• When will my maple tree begin green down? In 2007, Green Down began on September 23rd.
• When will green down end? In 2007, Green Down ended on November 27th.
• Will the leaves fall off the branches before snow covers them? No!  Snow covered them on November 21st and one leaf fell but the other three did not.
• Does my maple tree begin green down on the same day every year? I don't know yet, but I can collect this same data next year and then I will know!  Well...or at least I'll have a lot more evidence.  I might have to collect data for several years to be able to really answer this question well.
   
  Look here Leaf Color Chart 2007 Silver Maple to see all my data for 2007.

Day 17