Regeneration of Aspen in Boreal and Montane Forests of Alberta

UNKNOWN SPEAKER: Moist, cool conditions.

Used to be anyways,
getting warmer conditions.

And then we've got the Aspen parkland.

uh, compared to the prairies down
here, this prairie

this Aspen parkland is- is I'll talk to-
talk about that in a minute.

First of all, let's talk about the Boreal

The Boreal

We've got some of the,
some of the nicest

and most extensive Aspen stands,
probably anywhere in the world.

Sometimes 25, 30m tall.

And, a couple hundred, 300 meters

or hectare of wood
in these extensive stands

that go on for miles and miles
and miles. And,

you- you-

you can see the clonal structure in this,
in this particular scene.

So boreal aspen is
where most of the, the, the,

productivity that we're
where we're trying to grow it.

And after logging, or trying to fight it.

And when people are trying grow conifers

it's also distal

on the Aspen parkland zone
in the southern, southern

fringe of the boreal forest
and the springs of the grassland.

And in these areas,
we're seeing problems with the aspen.

We're losing the aspen
because of, because of, the drubs

So first of all, the aspens are
a lot shorter, or stun- stunted

5 or 6m tall in many cases. And,

we- we have this problem,

I guess, Doctor Sinclair showed
this before lunch

where you got, drought, cavitation
of, of these aspen stands.

We're losing
a lot of the aspen stands in this zone.

So the rest of, the rest of
the few minutes that I have,

I'm going to talk about a bunch of
research that we have promoting Aspen.

And, some of this will seem
a little odd to you because,

we're dealing with colder systems
than- than what you- you are.

And we're dealing
with more competitive species

probably than competitive,
other competitive associated species.

Okay, first of all, we talk about a study

that we did on the root,
root structure of aspen.

And we- we did a bunch of these,

wash studies where we wanted to examine

what's going on in declining aspen stands

are the root systems in good shape

So we had a dead aspen tree
she's got her hand on here

the roots in good shape,
and we see that

roots of these- roots
of these declining stands

Often we'll have a dead

tree, will often have live roots
connected to the rest of the clone

So these, the rest of the clone
is still capturing and taking advantage

of the life of the roots of the dead trees

We're seeing uh, uh

Root grafting at the base

of the stumps, commonly within clone

We don't see much root
grafting across clones

but within clones we see root grafting

we're seeing original roots.

root connections that are
80 years old,

as old as the original- original stands
that are connecting the Aspen.

In these, in these places.

So this, this is published
and you can,

I'll give you some places
where these are published and you can

you can get those
if you like, like to see those reports

That's, that's project one

second project is on seedling recruitment

And this is a, this is, a common thing
that we're seeing

in, in Western Canada.

We're seeing a large amount
of Aspen recruits

into zones where we didn't have it before.

It's coming in.

It's coming in into places.

This was originally a jack pine
or a lodgepole pine

And, and black spruce,
stand in the upper foothills.

This zone is usually too high in elevation
for the, for the aspen to live.

And, but not anymore because probably

because of climate change, warming,
warming up the summers in the spring.

We're seeing these aspen, aspen seedlings,

coming in very extensively in these zones.

And we're, we're expecting to see
a large amount of this in the future.

So we think that if you disturb the ground
significantly, you get 1,000 pounds

per hectare of aspen
coming in from natural seeding.

So it's a common thing to see it.

Here's a, here's a track from,
from a site preparation from alpine.

But they also promoted
Aspen to the chagrin

that the people were trying to go find.

They don't like this because the Aspen
is coming in at a at a heavy rate.

And we're seeing that,

the mineral soil is, is a term
we use to describe

where is the aspen relative
to the amount of substrate available.

So it's five times as likely

to be found on mineral soils relative
to the amount of mineral soil available.

Then something like
deep organic substrates,

which is almost nothing

so shallow organics or organic mix,
you'll find it.

So mineral soil we can we can get
we can get aspen

seedlings established from quite commonly
even on convex surfaces.

We did did that analysis of that as well.

The other thing we did is
we we actually aged a bunch of these Aspen

we aged 60 of them in this
in this population carefully aged

and cut them cereal section up the stem

and found out exactly how old they were.

And we found out that this was a seven
year old standard that pictures taken.

And we have seen
this all the way from 7 to 1,

and they were coming in every single year.

So this is not an uncommon event.

It happens pretty well every single year.

So the reason why we think it's
so common here is

we got a lot of June and July rainfall
right after see faster, see dispersion.

So I guess wouldn't podcast records
or flat or something like that,

but seems were more likely to record
on depressed microbes, topography.

And the main message is
we think it's spreading upslope

into the Canadian Rockies
from where it where it wasn't before.

And and we're we're just about
because it's ready for publication.

The third area we worked on.

Recently was on the last while we're still
still doing some work on this, actually,

following this up, where we we identified
a bunch of carbohydrate storage

and mobilization
in, in the aspen aspen cores

and where it where the carbohydrates

at different times of the year
and different and different seasons.

So we have cores.

You can see them very
nicely at this time of year.

We identified them and

then follow that same form,

cannibals, clones for a number of years

to, to,

measure things like root

carbohydrates and root stems and branches.

And, we did this, and some of the plants
actually got defoliation.

I'm not going to talk about that,

but we'll we will publish that work
eventually.

Okay.

The theory is
the theory is that, you know,

the one of the things we wanted to look
at was this whole issue of, that

leaf question and the growth of the Aspen
in the, in the spring times.

The top of the aspen

is related to this mobilization
of carbohydrates up from the roots.

Well, it's probably not the case.

We don't think we we don't see it
coming from that, that source.

We don't see any depression
from, roots, carbohydrates in the spring.

What we do see is a depression
and a mobilization

from carbohydrates in the tops
of the trees to drive the leaf rusher.

Okay.

So that's
one of the things we learned from this.

The second thing is in the summertime,
we see a large amount

of mobilization
of carbohydrates down into the roots.

In the summertime.

And so the roots are just being filled
right up with carbohydrates.

If you if you measure them

into late summer into early fall,
they're full of carbohydrates.

But if you measure them again
in really late fall,

at the time when things are just freezing
up, the ground's freezing up.

They've blasted it all the way again
because they grew a whole bunch of roots.

And there's nothing.

Carbohydrate reserves are pretty well
right where they were,

at the beginning of the season.

So almost all the way back into into fall
root growth

at that, at that, late in the late summer
or the late fall.

So we're not seeing
when I'm seeing this big groups,

mobilization from top to bottom.

We're seeing the roots once, the roots once they got the carbohydrates to hang on,

and they're using themselves.

So I always spring the early spring.

Spring prior to should flush with
carbohydrates are really low.

And power structures.

Okay.

So you harvest and machine
traffic is another another study.

So we wanted to follow this up
a bit of business of,

whether or not the season of harvest
is really important for

or whether whether or not Aspen
can recycle very vigorously.

So we, we actually looked at winter,
summer and fall logging to see whether

or not the aspen will suffer differently
under those under those systems.

Okay.

And we actually wanted to compare it
to the importance of soil disturbance,

because we know that winter
logging has way less soil disturbance.

And then summer flooding.

There's way more
there's way more disturbance.

So those two factors are confounded
season and disturbance that can follow.

So we actually set up a study where
we looked at those things simultaneously.

First of all, we we measured we set up
this very large site as a 50 by 50 meter,

sections of forest.

And there's four of them here.

And they were like to get summer
harvest, fall harvest,

winter harvest and harvest control.

And then we went into other parts
of these blocks and the corners and places

where we had sort of, we thought
was typical traffic and put in other plots

that we assessed
after conventional harvesting.

And the way we harvest events
is we harvest them with table skitters.

So we actually in the in those blocks,
we didn't drive over

and traffic everything up.

So we came all the the logs out, didn't

drive over the cost
of cutting with the chainsaw.

And then we compared that,
we compared them for the long

and the short is that season of harvest
is little different for all sectors.

Well, we all had about 50 to 60,000
tons per hectare of suckers and density.

Size in this area
was pretty much the same.

So if you don't traffic it, it doesn't
make hardly any difference at all.

So season of harvest.

And that really fits
with the carbohydrate, results

that we just reported. Okay.

But the machine traffic
did make a difference.

Density
was not affected by by machine traffic.

This is conventional conventional machine
traffic and no traffic.

And but the heights without the leaf area

and dry biomass, of the suckers was down

so they didn't grow as well
for your machine traffic compared to,

compared to where it was traffic.

Season brushing.

And, you know, asked.

There's a large amount of discussion
about trying

to try to,

control, but here's, here's

the different realities
that we live in compared to you.

We're trying to control Aspen,
and we want to do it with a brush size

and have slow growth rates now
so we can establish conifers.

And the

idea is that, well, if you log,
if you harvested or do this in wintertime

versus in the in the summer time,

you should have different results
at the end with carbohydrate.

Here it comes up in this one again.

And we measured the carbohydrates
in these.

And we, we.

We we did it.

We did this in spring summer as and winter

and again
the little difference in the current

in winter, spring and summer in relation
to, season of cutting.

We couldn't
we could not see the difference.

We had ten, ten reps of, of a large,

multi multifaceted experiment

just published in Air Force volume that.

But we did see this kind of thing.

If you do cut

and Aspen stem, you're not going to get
a good or very, very good Aspen.

But most of the response and after cutting
and asking the same way, the press,

come back as stem sprouts and we know that
they're likely going to have

root diseases or stem

diseases, associated with that.

Okay.

A fifth step, mother, study this one.

This one's related to fields.

And we have
we have large amounts of stands

with large numbers of stands
where we had hazel or sometimes alder

or sometimes you even come across
this in a very thick is grass

growing in the understory of these mature
aspen stands.

Prior to logging,

we cut these stands and we don't generally
don't get, regeneration.

These are many.

These hazel stands probably have
as much leaf area as the Aspen oversaw.

So huge amounts of huge amounts of,
vigorous,

figures, from and in some cases.

So what we did is we get
we have ten pairs of these stands

where we had a high density haze
or 50,000 snaps per hectare, versus about

3500 sets per hectare.

We had ten pairs of them,

adjacent pairs that were within a few
few meters of each other.

And we we locked these, we log these

and we carefully logged them into
to not traffic here.

We didn't drive over these.

We just reached in with this other bunch
or grabbed the logs.

I've never dropped scatters through them.

So there wasn't traffic issue compared
to the area where there wasn't a hazel.

And then we were we measured
a whole bunch of characteristics.

We measured the suckers,
the sucker, regeneration.

We measured the root development.

We were interested
in the roots of the aspen.

We because we thought our hypothesis
was that the the Hazelwood

would essentially drive down the root
biomass of the of the aspen stands.

The vigor

degree would be down
because of this, this aggressive,

competition from the Hazel.

We then we measured, we actually went in
and went to that, went into the stands

and we measured the roots and turns,
dug some root pits.

And, when you have a graduate student
only weighs

100 pounds, you have to get fossil fuels
involved to help out.

And that's what we did here.

We we dug these.

There's a whole bunch of these tests with.

I think we had,

100 of these pits that were done.

What you get is, cleaned off a face,
put a mylar sheet on it,

and then marked all the all the aspen
and the

and the hazel roots on that sheet,
and then brought it back to the lab

and did it and did council analyzes
in terms of the distance above ground,

distance into the ground.

And what we found is there's a lot

there was a significant drop in insect
density.

There's still lots of suckers,
but they were.

Quite a bit, quite lower than where.

You didn't have Hazel, locomotive.

Hazel.

I, tended to be down,
but not was not significant.

And so we were trying to
we wanted to look at the roots

of pruning in relation to, to this problem
as to why there would be less,

less, less, Hazel, less effort.

What we saw is that the surface roots,
we had fewer

surface roots in the places
where there was hazel, the aspen,

the aspen was driven down to lower levels,
totally todas as many aspen roots.

But the surface roots were down.

And, when you look at the suffering,
and that's probably what happens,

because you have the suffering is all
from the surface roots and in our as well.

And that's why we
we saw this decline in numbers,

another project
looking at root warming and suffering.

We we did two different treatments here.

We cut roots,

we cut roots and we scraped roots

like logging equipment would do to see
what impact that has on on suckering,

whether or not that's a positive thing
or a negative thing.

And then we measured the numbers
of suckers in the height of height of the.

Tallest suckers,
and we had the suckers after us.

After growing.

And we did find actually greater numbers
of roots.

Associated with wounds,

just about double the amount of, of, of,

of suckers that were associated
with scrapes or severs

compared to the control.

So injury roots generate

more suckers or taller suckers and suckers
with greater leaf.

And we published
just recently in the nature by our

we're doing some other work on this
that looks at even more damage.

More damage
and more damage is is giving giving us

lots of suckers
but miserable little scarring things.

They just don't grow properly. So

warts doesn't always mean good.

Okay, last time physical barriers

where we wanted to look at this issue
of physical barriers and suffering

and whether or not it's things
that are actually stopping

and preventing the suckers
from moving out of the soil

or moving through their substrates
above the soil,

are important forces in subtle.

And so we we,

looked at a particular is a problem
with a grasp of how an across the rifle

omnibus grass
notice inhibits suffering of asthma.

And we've got lots of examples of this
where we have

where we had an Aspen stand,
it had came across the in the understory.

The grass, dominates the site.

And the suffering comes in very poorly.

It grows very slowly.

It's very, very poor for performance.

So we
think part of the problem is called soils.

And so that's a given.

We're going to I'm not going to I'm
going to move on from there.

But we did do well.

We did do an experiment.

And we have an experimental system here
where we grow aspen and root plot

root, window boxes within its root.

And these were the boxes
for three years, grass.

And we've come across this
in the window box for three years.

And you asked what works

if you fertilize and water it quite well,
grows quite nicely in this situation.

We actually couldn't see any difference
in root mass or anything like that.

And we fertilize.

We did have had a fertilization treatment
in this experiment as well.

The main point I want to get across here
is that the the come across this,

really slows down the

suffering of the in terms of,
in terms of its movement out of the,

out of the, the soil as well

as its growth once it got out of the soil.

And this is,
this is what essentially we have.

Numbers are suckers in relation
to come across this principle.

For us, it's a no counting process.

And there was fertilization
or no fertilization.

If you if we have immersed suckers,
they actually got out of the soil

versus suckers that were formed
but never got out of the soil.

Okay.

So these suckers here are in the soil.

They never they're never make it out
over a 50 day period after after start.

So they're still in
for all these together.

There's no there's no difference
across any of the treatments.

But there is a difference in terms
of whether or not it's come across this

or no come across in terms and numbers
that get out of the soil.

Okay. Just about about

the main

thing that's going on, we think, is this
is that the, the, the dense sods,

the dense sods and are acting
as a physical barrier that are stopping

this coarse, thick, fleshy aspen

sprout from getting out of the soil.

And we get the same thing.

We did another experiment
where we did it with aspen litter

above the soil, and the aspen litter
prevents the aspen from growing.

Once it gets out of the soil
and it slows it down by 2 or 3 weeks,

that's a big deal in our part of the world
where we have a very short crisis.

Okay, no effects.

No effects of numbers of suckers
come across.

This is a physical barrier,

resulting in fewer suckers
getting out and come across is delayed.

Delayed
emergence is the later delayed emergence.

And we're seeing the same problem
on logging decks in places where there's

a lot of a lot amount of slash and debris
on the site,

the physical barrier,
we think is very important.

Okay.

And here's some of the people
who helped fund all this work.

And if you've got any questions,
I hope I got time for 1

or 2. Yes.

Maybe I'm just I didn't hear
quite right, but, so you had logged.

The logging equipment.

Didn't seem to stimulate
a lot of extra suckering,

but when you went in and injured,
the was a stimulated.

Suckering and a separate study

when I personally been on the ground
in, South Dakota, where I saw

some logging equipment going up there
was, there was massive sector coming up

and we lost the and other parts of this,

region, some brute ripping
and getting a lot of suckering.

Maybe you could explain the difference or
I've missed something between those two.

Yeah, I think that,

that's an interesting problem
with logging, logging and other wounding.

I think if you have a simple wound,
simple wound,

such as with a site preparation equipment
where you have a nice long time

cut through the soil
or something like that,

you probably will stimulate a net.

There'll be a net stimulation of suffering
if you've got a large

and extensive amount
of wounding on and aspens on aspen root.

We're seeing that,

if you come and dig that root
that that root up in in a month,

it's got,
it's got multiple pockmarks of wounds.

And you can see the,
the fungi and the blackening of the stems

of the roots along those areas
around every one of those wounds. And,

so I think there's a distance factor here
that's important.

And how much and how much,

how much reserves.

It's got to fight off that.

Fight off that, that disease has disease

vectors that are, that are entering
every one of those wounds.

Yes. It's,

spring leaves up instead.

The stem and mostly twig and upper

and upper, foliage, upper crown.

That's what we saw.

After the leaf off, we see a depression
in carbohydrate concentration there.

We don't see it in the weeds.