This course surveys the diversity, structure and functioning of California’s ecosystems through time and the ways they have influenced and responded to human activities and stewardship. Topics include ecosystem drivers such as climate, soils, and land use history; human and ecological prehistory of the state; comparative marine, freshwater, and terrestrial ecosystem dynamics; and managed ecosystems such as range, fisheries and agriculture in California. The course also emphasizes important skills to understand as a scientist or consumer of scientific information, including data collection, natural history, and writing.
Forestry
Loading...
Del curso dictado por University of California, Santa Cruz
Ecosystems of California
15 calificaciones
Explore Related Videos
At Coursera, you will find the best lectures in the world. Here are some of our personalized recommendations for you
De la lección
Drivers of Statewide Patterns
Conoce a los instructores
Erika ZavaletaProfessor
Ecology and Evolutionary Biology
[MUSIC]
I am Erika Zavaleta and this is Ecosystems of California.
And today, we're looking at the practice of forestry which is the management
of timberlands for the sustainable meeting of societal needs, values and desires.
In the California Ecosystems, in which forestry is practiced range really widely.
They include a variety of the mountain forest types in the Sierra Nevada.
They include the coast redwood forest and mixed evergreen forest of the coast.
And they also include certain kinds of oak woodlands.
But today we're visiting a highly productive kind of forest
in California that's a big part of its history of timbering and
that is the coast redwood forest type.
Forestry, as a practice,
I think it's often just sort of set aside as a threat to ecological systems.
And one of the things that we want to talk about today and
explore is the ways in which forestry has evolved
at least in the best of circumstances to be really compatible with a much
broader range of goals than just the economic extraction of wood products.
So, the visit we are making today to the San Vicente Redwoods in Santa Cruz County,
California is an opportunity to look at how forestry
pulls together meeting the need for an economic flow of revenues
with the demands of maintaining and improving wildlife habitat,
native biological diversity, watershed values, and
a host of other ecosystem functions and services that are also valued by society.
Logging and forestry have a long history in California and over time they've
taken place on only about 30% of the forested lands in California.
The other two thirds are protected in various ways as parks,
reserves, and lands that are set aside for other kinds of uses.
And of that 30% of California's forested lands that are harvested,
about 60% are federal lands managed by the national forest service.
And then the remaining 40% or
so are privately owned like the property that we're visiting today.
So we're in the San Vicente Redwoods in Santa Cruz County with Nadia Hamey who is
a forester responsible for managing this property.
Nadia, thanks for joining us today.
>> My pleasure.
>> Can you tell us a little bit more about this property that we are on today because
it is a very unique one from the perspective of forestry.
>> So, this property was owned by a cement company in Davenport for
at least the last 100 years.
And it was purchased in 2011 by a conservation partnership made up of
Peninsula Open Space Trust, Sempervirens Fund, Save the Redwoods League and
the Land Trust of Santa Cruz County.
And it's a pretty exciting, new kind of way to care for conservation land.
There is a conservation easement held by Save the Redwoods League that has
dedicated portions of this property and perpetuity to working forest,
as well as preservation reserve, and restoration reserve.
We're in the working forest part of the property now,
where we plan to implement sustainable timber harvesting on a rotation.
Which will, over time, increase the average tree size, and
accentuate our wildlife habitat and help turn our water course and
lake protection zones into more of a lake serial or old growth character over time.
While in a matrix of the majority of the working force,
being managed for sustainable wood production.
All of the revenue from the timber harvest will go back into the property to
do road maintenance.
There's about 70 miles of road on this property, some of which will need
resources to abandon, others will need resources to be maintained and upgraded
to be able to handle 100 years storms without causing erosion and sedimentation.
Particularly in proximity to our water courses.
Other portions of that revenue from the timber harvest will be used
to implement evasive species control.
And work with volunteers on that.
Also, cool projects that will improve the aquatic habitat on the property.
We are right now working on a large woody debris installation project
along San Vicente Creek to increase the habitat value for
salmonids, make more pool and high water refugia and
hopefully activate the floodplain in big storm events.
We're also currently in the preliminary stages of setting up to do
a prescribed burn along a portion of the shaded field break on this property.
So all the resources from the timber harvest go back into our really long
list of opportunities to improve the habitat quality on the land.
And at some point,
portions of this property will be opened to public access and so we'll be able
to showcase the various efforts that are being made in all of those regards.
>> I'm right above that tree you and Adam were at.
When you guys split, you can walk up here now.
>> Okay sounds good, we'll see you shortly.
Shall we?
How's it going?
>> Better today.
>> Good.
>> I smashed one of my jacks yesterday, >> No.
>> On like a $5 tree.
It's like a $2000 jack.
>> Serious?
>> But, >> Sorry.
>> Luckily, there's still some parts for it.
>> We are here in the San Vicente timber harvest plan,
with one of the timber fallers contracting with Big Creek Lumber company.
This is Brett Lambert, he's pro.
>> [LAUGH] >> [LAUGH]
>> I've done it for awhile,
made a few mistakes so that adds up.
But I try to keep those to a minimum.
So like, she comes through and she picks a tree, puts some paint on it, and
she's got it, like this is an old skid trail that we're standing on.
The tractor had been here at one time.
And so that's the first objective,
is like whatever means you're taking the wood out, you have to have,
like, that tree has to be able to be put where the equipment can get to it.
So she's looking around, getting her skid trails,
her access established, picks a tree.
And then my job is to come through and put the tree where the equipment can get it.
But my job is to not damage these trees or
at least look at them and have that in mind as I'm trying to
put this where it's not going to damage all these younger trees.
The first thing you do is you look at your weight.
The original tree that they took sprouts come around that stump.
And so they all try to grow out where they have space.
So they're going to have like limb weight that's going to persuade them just like
anything if you hang something off, that's going to pull it.
So you're looking at like this tree, it's hard to get a real good read but
you could send it off over here but that's not the best for the equipment.
I'm going to put it up here, where above that bigger tree,
kind of angle it out there.
But it's just something you develop over time.
You just get a sense whether it's straight or not.
But I have to assess which way it wants to go.
If it doesn't want to do what I have to do, then you use these wedges, or
like that one I jacked.
Just because it was too much weight. So the physics of it is the first cut,
you open up the tree so that it can move without just freely.
The wood that you leave is called your hinge.
So you open up the front of the tree, that's your undercut.
The back cut comes in.
And then that wood, as long as it's square,
then that tree just pivots off of that, that's why they call it a hinge.
And then the saw has sights on it.
And all saws have them, you just don't notice them.
But it's a line, it's a 90 degree angle to this part of the saw.
So that's just like looking down the sights on a gun or something.
So that's how you point it, then you match up that undercut.
The whole idea behind the undercut is so, as long as that's moving freely,
it's not pulling on that hinge wood too hard.
Once you pull on that hinge, it gets to the certain point, it breaks.
And by that time, you hopefully have most of the weight going where you want,
just kind of drops down there.
I've been doing this since 1985.
School wasn't my thing.
So the only school I've done since high school's traffic school.
>> [LAUGH] Since the clear cut, so since it was pretty much level,
there have been three selective harvests.
So this will be the fourth light selective removal of individual trees,
and so we have multi ages happening here.
This'll be causing a fourth new generation of redwood trees to sprout.
>> If you clear cut, then everything's at the same age as it grows.
So your growth rate, these trees, you wouldn't get your height as much.
When you have, these trees have to reach to get sun, so
that's promoting them to grow up, as opposed to just grow out.
So that's what's nice about having an existing canopy that they're working with.
[SOUND]
[SOUND]
>> A lot of times with the selective
harvest, you have pretty rapid growth rate at the beginning, and then it slows,
slows down.
And then at some point, there was a tree harvested around it,
one of these second growth stumps, and it sped up again.
And I don't actually see another pulse of slowing down really,
maybe back here a little.
And one of the things that fallers in this area do a really good job at and
focus on, is having really low stumps.
So that you can see Brett's bar was almost in the dirt over here, and
that helps the new sprouts have a better footing.
If there's a high stump, they might grow right out of the collar of the bark, and
then they aren't anchored in the ground.
>> Like that tree right there,
can you see that little tree on that stump?
because wherever these things are cut, and a ring of sprouts will come around them.
So by being on the ground, they come out of the ground and stood on top.
>> And also, that when you have low stumps,
it helps because you might hit them in future harvests.
>> Right.
>> So if they're sticking up very high,
they're more likely to cause breakage of the tree.
>> They're more of an obstacle >> That you remove in the future.
Redwood has a kind of unique ability to both split and fuse rings.
So they are very confounding sometimes to dendral chronologists.
Dendral chronologists are the people who look at the tree rings and
reconstruct the story about the history.
You can look at carbon and
oxygen isotopes, and figure out the climate of that year.
And what the rings represent is the early wood,
is the main growth season, that's the lighter part.
That's when it's really growing,
when it has available moisture in the spring and summer.
And the late wood starts when it becomes moisture limited, around August and
September, and it then stops growing for the year.
So each set of a dark and a light ring is a year of growth.
This tree had a pretty life without scars at the base or
fire defect, except for right here when it was four years old approximately.
It had- >> That could have been when they were
logging it.
>> When they clear cut, they would fall the timber and then have a broadcast burn
in order to get rid of the slash and make it easier to pull the logs.
And at that time,
they were moving logs around with a steam donkey and putting them on a railroad.
And so,
sometimes there's damage from that first fire when they had initially regenerated.
because a lot of times it's not literally burned, but it's just so much heat.
It's just like a wound.
>> And in areas that are on the edge of the redwoods, so
right here we're pretty much surrounded by redwood, but
where you're on the transition zone between redwood and knobcone pine which
burned with much more intensity >> The fire severity was higher and
you have a lot more defect or
a lot more evidence of fire around the cambium layer.
And many times it's on the upper side of the tree where duff and
litter accumulates.
And also particularly where they are growing next to an old stump that
smoldered and burned for quite a while and built up the heat.
That's where they have that defect introduced, or that scar,
but you can tell a lot from looking at the tree rings.
>> So Nadia, tell us about when you get to the marking stage, after you've gone
through perhaps a couple of years worth of planning with the various
agencies responsible for working with you to protect wildlife and other features.
You get to that stage, it's time to select which trees are going to come out.
Tell us a little bit more about, in that phase of your job, what is your day like?
>> Well, I consider that to be the most important part of my whole job because
of the indelible impact that I am leaving on the forest structure by
selecting individual trees >> So it's really mind and body taxing.
Because I'm hiking all over, up and
down the hillsides in order to get a good vantage.
I like to oftentimes approach a grove of redwoods from multiple directions, so
you have a different perspective.
I'm scrutinizing the tops and the base of the tree.
I'm thinking about wildlife retention.
I'm thinking about having a good leave stand and nice stalking in
order to grow, have enough volume to grow a productive forest for the next phase.
I'm really thinking a lot about the physical constraints of the harvest,
where the infrastructure is, how the trees will be yarded out once they're felled.
And the different considerations that the timber faller
has to think about when they're falling the trees, such as their lean,
their weighting of branches, all of those features.
And it's a very heavy decision to put that mark of death on a tree,
which I do a horizontal stripe at about eye
level all the way around the tree and I do a stump dot.
And often times the stump dot is unique to the person marking the tree so
that you can verify that it was marked by the forester.
I can barely do this activity for eight hours a day because
it is such a complex thought process with every tree,
so many different considerations.
It's kind of exhausting.
So after all of the review and contemplation that went into putting
the plan together, it's really where the rubber meets the road.
It's the most important part, and people will be able to look back on
the influence that I had on this forest's development for many years to come.
So, a lot of responsibility.
>> Yeah.
>> But I love it.
It's exhilarating, especially when doing this type of selection.
Because you can really make a forest look very
nice immediately after a selective harvest, if you choose correctly.
Out here, we're blessed with the ability to be thinking really long term.
It's not all about the bottom line, it's about responsibly managing our resources
and improving forest health,
especially in an area where we just had such a significant fire.
So I've assessed this whole area and looked at the trees,
and I've decided which ones to mark.
And this is one of my candidates right here.
Part of the reason is because it's spaced between two nice dominant redwoods,
and it will release their crowns up above and
allow the branches of the neighbors to elongate into that growing space.
And the other is partly a salvage reason because it has this fire scar
when it burned.
Six years ago, the stump next to it really burned for
quite a while and burned off some of the duff layers around the roots.
And so as you can hear, it has a hollow layer below the bark.
So in order to let the timber fallers know which trees to mark out here,
I'll put a blue stripe on and a stump dot down at the low point,
in order to indelibly leave my mark so I can verify that I marked the tree.
It's my stripe of death.
But it's in order to release these little guys, which are the next generation, and
they're all around us.
And there are about three different age classes in this growth.
So we can perpetually choose about a quarter of the trees to remove every 15 or
20 years and keep this cycling and producing and
also valuable habitat and vibrant at the same time.
[MUSIC]
Explora nuestro catálogo
Inscríbete de manera gratuita y obtén recomendaciones personalizadas, actualizaciones y ofertas.
Coursera brinda acceso universal a la mejor educación del mundo, al asociarse con las mejores universidades y organizaciones, para ofrecer cursos en línea.
© 2019 Coursera Inc. Todos los derechos reservados.
