When I graduated in 1967 I had no idea what I really wanted to do but was facing the draft.

I learned that there was an opening for a position as a pilot trainee in the Massachusetts Air National Guard.

So I spent the next six years looking down at forests.

This is a black birch.

Both black and yellow birch have a wintergreen smell.

Over the past 30 years have you been using your nose a lot to?

Yeah, yeah.

Yeah, it's very helpful.

Fortunately I haven't had COVID yet.

I've been doing this walk that we're doing for 32 years.

John is like the quiet sage.

More than a teacher or a scientist he's a noticer.

These are original data sheets from the early ‘90s.

I originally started this to get outside and walk in the woods on a regular basis.

We have all these really fancy high-tech ways of collecting data.

The fact that we still rely on the stuff that he does on the ground is just incalculably valuable.

Over the years I've been doing it, it has become of increasing interest because it is one way to look at how a changing climate is affecting New England forests.

When I start my observations in the spring I try to get out before anything is really happening.

You can actually see that these buds are starting to swell.

That means that they're primed.

And if we have a week of warm weather the leaves come out.

If we have two weeks of cold weather, nothing's going to happen.

So the first two to three weeks of April are really the critical period for determining whether it's going to be an early, a normal, or a late spring.

In my study, I'm trying to track the growing season the time from when the leaves come out in the spring and develop through the fall when they turn color and drop their leaves to go dormant over the winter.

These types of observations are called phenology.

The first event that I'm trying to record a date for is when the leave actually emerge from the buds.

A bunch of these have have just emerged and you can just see the base of the the leaf, which is what I call leaf out.

The only trouble with a beautiful day is that the sun gets in the way when you're trying to look up into the canopy of a tree.

Phenology is driven by the weather in a given season.

This paper birch the majority of the leaves are out.

The plants are responding to the weather that spring or that fall.

Weather over a very long time frame is what is defined as climate.

And the climate is both becoming far more variable and changing.

Canada mayflower.

Maianthemum.

The flowers you can see the flowers, but they haven't opened yet.

Although the climates warming, the weather is still very variable.

This amazing variability does present risks to the trees because a late hard frost can nip the buds and set the whole process back.

Other than the oaks, there's very little green left in the canopy.

Even since Sunday the trees are a lot less leafed.

A lot came down.

That's just just amazing to look at that.

In the fall, I observe what percent of the leaves are not green and what percent have fallen off.

This process is called senescence.

The falls are getting warmer.

The frost dates are dramatically later.

It was not uncommon to have mid-September frosts in the ‘70s and 80s.

We haven't had a September frost this century.

I've been making my observations at the Harvard Forest, about 60 miles west of Cambridge.

And this is the least developed part of Massachusetts.

This landscape has served as a research forest for over 100 years.

We are trying to understand how the forest has developed over time and where it may be heading as we go forward.

All of this is intertwined and my study is in conjunction with other long term studies at Harvard Forest.

And it's not centuries.

It's a scale and a time frame that fits fairly well within a human scale.

A lot of what we look at is seeing what's happening at the big scale.

And a lot of what we look at in studies is the microbiological level.

And this is an intermediate scale where you're looking at whole plants looking at them closely and repeatedly over a long time frame.

I think the real value of my study is that it provides on-the-ground observation of how the plants are really responding to the environment.

White ash tends to be the first tree here at the Forest although that's a... another story because we're losing the ash to an ash disease.

None of my original ash trees are still alive.

And in fact I've basically almost given up trying to find ash to keep following.

Eventually the ecosystem will shift.

It will continue to function but it will function differently with the loss of a species like ash.

And in a sense, you know, our our concern about climate change is its the impact on us.

It's not... the ecosystem is going to change.

And whether it changes in a way that we're far less adapted to that's the problem.

Life isn't going to go away although people may have a much-- more difficult time within it and potentially go away.

That's much more likely.

Altogether, I probably spent over 4000 hours over the course of the study.

When I started doing this in 1990 I wasn't thinking of it bein an estimate of climate change, because that wasn't in my mind at the time.

But as climate change worsens, my work is becoming of increasing interest.

Over the time I've been doing it of course, it really has become one of the more cited research data sets at the Forest because it is both very long term and it is related to the changing climate.

I'd be fairly willing to say that yes, our falls are getting later.

But I really don't have an ability to say what's happening in the sprin other than it's very variable.

I suspect that even another another 30 years would, I think especially given the way the climate is not we're not we're not addressing it.

I would expect that we woul start to see some, some pattern.

I won't be doing it but I'm hoping that someone will continue this here because we're starting with over 30 years.

You're well on the way.

My view of time, I'm sure, is not independent of the fact that I'm also aging.

And so that also is a major influence on the way you think about time, not just the study I'm doing, but also thinking back over a lifetime and a career.

I think that it's made me more comfortable trying to think in a broader time frame.

Let's see if any of the star flowers are up yet.

Ah, yes.

They were all over the wall, right?

Or no, that was over by the barn tower.

By the barn tower, yeah.

So we definitely have some bud break for the sugar maple.

What do you think about 80%?

I'm thinking that sounds good.

“MS”?

Yeah.

Even some that are still just slightly swollen, I think.

Yeah.

Im in the process of working with Greta VanScoy.

She has been shadowing me in anticipation of taking over the project.

We have to get the little hawthorn, right?

Have to get the little hawthorn.

You can actually still see it because the leaves of the things around it aren't out yet.

Have to pick the path, though.

--Yeah, some of those are open.

--Yeah.

Yeah.

Actually, I think that's 100%.

All right, so... We are comparing our observations to make sure we are on the same page, so the study will continue in the same quality.

This is a pretty important data set for Harvard Forest.

It's one of the most accessed data sets, so it was just finding someone to take John's place or to actually learn the route.

And I've done phenology before.

I've never turned down a walk in the woods and so it seemed like a really good fit.

It's definitely Harvard Forests study.

I happen to be the one doing it, but I'm reaching the point where I don't feel that I can continue it indefinitely, so yeah.

So what did you think for the leaf?

I think it's still “VS.” Okay.

Not quite-- --They're getting there.

--bud break.

Yeah.

This is a Harvard Forest data set, but this is definitely the John O'Keefe phenology loop.

And I think it's always going to be referred to that way.

--This is new.

--This is new.

Always got to be an obstacle, right?

Well probably get this out of the way in case anybody ever tries to drive out here.

Thank you.

And I also saw the first mayflowers out over the weekend too.

I haven't seen any out yet, but remind me you know where the first paper birch is?

There's a very nice mayflower clump right under it.

They're the best smelling flowers around.

Except they're not easy to smell.

You have to lie on the ground.

Yeah, exactly.