Tag Archives: redwood trees

Increased Atmospheric CO2 Is Increasing the Maximum Height of Old Growth Redwood Trees in Northern California

Note the information and assessments made herein are those of the author.  Some statements of facts and forecasts involve a degree of conjecture.

1       Increase in Atmospheric CO2 Since 1900

Atmospheric carbon dioxide (CO2) has increased since 1900 at an increasing rate.   This is due to the burning of fossil fuels to support industrialization, transportation, and home comfort.  Before 1900 the concentration of atmospheric CO2 was about 285 ppm and holding steady.  Now it is 415 ppm, increasing at an increasing rate, and will likely be around 500 ppm by 2050. 

For plants, CO2 provides energy for photosynthesis.  For humans, CO2 is a product of cellular respiration and must be released by breathing.  Increasing CO2 from the background level of 285 ppm up to about 1,000 ppm enables faster plant growth.  This is commonly done in indoor green houses.

However we humans have evolved over the past 200,000 years with CO2 at 285 ppm, now it is much higher.  In the same way increased CO2 supports increased plant growth, it is possible increased CO2 creates adverse issues for human cellular functioning.  Indoor CO2 levels over 1,000 ppm cause people to start to feel drowsy, an indicator of impeded brain function.

Plants:  Carbon dioxide + water + light YIELDS glucose + oxygen + water

Humans and other mammals:    Glucose + oxygen YIELDS carbon dioxide + water

2       Increase in Redwood Tree Growth Rates Since 1950

Studies of tree rings have shown redwood trees in the northern redwood parks have increased their growth rates markedly, especially since 1950.  Tree ring width since 1950 can average 50% per year more than what was experienced on average in the tree’s 1,000 to 2,000 years of life before 1950.

The northern redwood parks have not experienced adverse climate change like the southern redwood parks.  The recent droughts in the Humboldt and Del Norte county redwood parks were not as severe as those further south and there were no major fire events within these parks.   The increased CO2 has not led to substantial adverse climate events in the northern redwood parks and the redwood trees are increasing their growth rates in response to the CO2 increase.

3       Height Changes in very Tall Redwood Trees Since 2000

The increased growth rate in redwood trees is also expressed in increased crown growth, leading to increased tree height. It is documented theoretical tree height is limited to 425 feet or so due to how far ground nutrients can be pulled upward by adhesion versus the effect of gravity. For tall redwood trees this is partially offset by fog absorption but the demonstrated current height limit is 381 feet, with an historic height limit of maybe 400 feet. But for most of their lifespans the tallest redwood trees dealt with CO2 at 285 ppm, now it is 415 and going to 500.  So they may be able to get taller, all other things being equal.

To assess this, here are height changes in the tallest redwood trees by park that were measured somewhere around 2000 and then again somewhere around 2013.  So the height changes are over a 13 year period on average.

If redwood trees were experiencing their maximum heights then it would be expected the tallest trees in 2000 would grow less in the next thirteen years than trees that were a bit shorter. 

For RNP and HRSP this is not the case, the tallest trees grew just as much as other slightly shorter trees during the thirteen year period.   For MWP the tallest trees were suppressed, this is in line with the drought and fire conditions experienced by that redwoods reserve.

Humboldt redwoods 25 tallest trees measured in 2000 and 2013. Ordered left to right by descending height. Note tallest trees continued to grow at rate of less tall trees.

Humboldt Redwoods 93 tallest trees measured in both 2000 and 2013. Ordered left to right by descending height. Note tallest trees continued to grow at rate similar to less tall trees.

Redwood National Park tallest trees mesured in both 2000 and 2013. Ordered left to right by descending height Note tallest trees continued to grow at rate of less tall trees. Also note many current RNP tall trees were unknown in 2000.

Montgomery Woods Reserve tallest trees measured in both 2000 and 2013, ordered left to right by descending height. Note max height has been reached as tallest trees grew less than less tall trees. Park was subject to drought and fire during the 2000-2013 time period.


4       Tallest trees in 2050

It is likely the tallest redwood trees in the northern redwood parks will continue to grow, at an increasing rate, at least to the year 2050.  By 2050 the tallest trees, and the entire redwood canopy, are likely to be six or more feet higher than they are now.

So at least in part of their range, the redwood trees are benefitting from increased CO2.  As for people, the benefits are less certain.

Thanks for reading.

Redwood Thunder

1      Redwood Thunder

Redwood thunder is an uncommon but not rare event. It occurs when a large redwood tree falls to the forest floor, sometimes striking and taking other redwoods, firs, spruce, oaks, and maples with it. A cubic foot of redwood weighs 50 pounds, so if a moderately large 20,000 cubic foot redwood topples that is a million pounds, or 500 tons of wood crashing to the earth.

For redwood thunder to occur usually soaked soil and wind are required, though if the tree fractures on itself soaked soil is not an ingredient.  Sometimes before redwood thunder occurs the tree will lean against an adjacent tree, with the trunks and branches rubbing with the wind and making screeching sounds like giant stringed instruments.

All redwood trees eventually topple, or at least break off down to a low point on the trunk.  If a given old growth redwood has a one in a thousand chance of falling in any given year than that means, based on acres of old growth redwoods, the average annual tree fall count in the large redwood parks is about 300 trees, per park.

If there are multiple trees involved in a tree fall or if the tree falls across a creek, the tree fall is noticeable in Google Earth.  If you hike the same trails over several years you will for sure see trees that have recently fallen.  Their upper trunks are huge and their logs run sometimes more than a football field along the forest floor.

`

2      Examples of Tree Falls

 

Here are several examples of tree falls I ran across in 2016.  Included are a picture I took of the tree fall accompanied by before and after Google Earth views of the tree fall areas (using Google Earth historical imagery).

In Humboldt redwoods a neighbor of the big Dyerville Giant log fell in the late spring 2016.  Its trunk shattered and splintered into sections where it struck the Dyerville Giant log.

Tree fall across Dyerville Giant in Founders Grove
Tree fall across Dyerville Giant in Founders Grove

 

Founders Grove - tree to fall marked with X. (Image from Google Earth)
Founders Grove – tree to fall marked with X. (Image from Google Earth)

 

Founders Grove - space left by fallen tree marked by X. (image from Google Earth)
Founders Grove – space left by fallen tree marked by X. (Image from Google Earth)

 

Another recent tree fall in Humboldt was in the area where a seasonal foot bridge is put in to link the Rockefeller Redwood area to the Giant Tree area on either side of Bull Creek in the upper Bull Creek Flats.  The new big log is used a lot to cross the creek, though it would be a pretty tough eight foot or so fall from the log to the rocky creek bottom if your foot or the bark slipped.

Log across Bull Creek in Giant Tree area
Log across Bull Creek in Giant Tree area

 

Bull Creek Giant Tree area - tree to fall marked with X. (Image from Google Earth)
Bull Creek Giant Tree area – tree to fall marked with X. (Image from Google Earth)

 

Bull Creek Giant Tree area, empty area where fallen tree was standing marked with X (Image from Google Earth)
Bull Creek Giant Tree area, empty area where fallen tree was standing marked with X (Image from Google Earth)

 

A third fall in Humboldt occurred in Harper Flat.  The tall north side of a twin trunk redwood fell in the last couple years.

Harper Flat fallen tree, north side of pair (still from I Phone video)
Harper Flat fallen tree, north side of pair (still from I Phone video)

 

Harper Flat - tree to fall marked with X (Image from Google Earth)
Harper Flat – tree to fall marked with X (Image from Google Earth)

 

Harper Flat - area left by fallen tree marked by X (Image from Google Earth)
Harper Flat – area left by fallen tree marked by X (Image from Google Earth)

 

The final example is in an area of tall hillside redwoods on the east side of Redwood Creek a little north of McArthur creek near the seasonal foot bridge.  Here the tree fall took out a number of redwoods and the whole group of fallen trees is slowly sliding down toward Redwood Creek.

Redwood Creek tree fall area, trees are slowly sliding downhill.
Redwood Creek tree fall area, trees are slowly sliding downhill.

 

Redwood Creek hillside above north seasonal foot bridge, trees to fall marked with X (Image from Google Earth)
Redwood Creek east hillside above north seasonal foot bridge, trees to fall marked with X (Image from Google Earth)

 

Redwood Creek east hillside above north seasonal foot bridge, area where trees stood marked with X (Image from Google Earth)
Redwood Creek east hillside above north seasonal foot bridge, area where trees stood marked with X (Image from Google Earth)

3      What Can Be Learned From Fallen Redwoods

 

A recently fallen redwood is a great opportunity for whole tree research once the soil in the fall area has stabilized.   The root system and affixed soils can be studied without any digging, this is the big primary benefit.  But also core samples can be extracted without having to climb and core living trees.  The canopy structure can be measured and reviewed without climbing and an unlimited amount of destructive sampling can be done.

Thanks for reading.

Record Breaking Redwoods Outside the Redwood National and State Parks?

1      Tall Forests – NASA Canopy Height Mapping

 

NASA maintains a global canopy height map on its website. This map is comprised of airplane based LIDAR mapping (2.4% of land mapped for canopy height) and satellite based “spectroradiometer” equipment (97.6% of land area mapped for canopy height). The canopy height is appropriately in shades of progressively darker green with the darkest green indicating at least eighty percent of the tree canopy in the area is over 70 meters (230 feet).   All the dark green areas in northern California are old growth redwood stands.   The average tree height in old growth stands in northern California is 250-300 feet, with maximum demonstrated individual tree height at 380 feet.   To see more on this subject see my posting on “Distribution of Tree Height in an Old Growth Redwood Forest”.

Below is a portion of the Global Canopy Height map that includes the area from Fortuna to Klamath. The dark green (old growth redwood) forests have been noted from north to south.   The old growth forests include Prairie Creek Redwoods and Redwood National Parks. No surprises there. However there are five additional areas with large enough tracts of old growth redwoods to be discernable on the global canopy height map.

You can click on the map to see a larger version.

 

NASA Global Canopy height map - Eureka to Klamath
NASA Global Canopy height map – Eureka to Klamath

2      Lesser Known Areas With Old Growth Redwood Forests

 

From north to south here are some comments on the lesser known areas with old growth redwoods forests.

Six Rivers National Forest High Prairie Creek Section and Yurok Redwood Experimental Forest

This area is low elevation and is protected from the ocean by a large ridge and has riparian zones along High Prairie Creek.   These are perfect conditions for large and tall redwoods and indeed there are many large tree crowns in this area as seen on Google Earth.

This area does not have any public access and most requests for special access will be declined.

This could be the best area for old growth redwoods between Prairie Creek Redwoods State Park and Jedediah Smith Redwoods State Park and the trees in this forest are representative of the redwoods found in those parks.

Yurok Experimental Forest and Six Rivers NF near Klamath
Yurok Experimental Forest and Six Rivers NF near Klamath (Google Earth view)

 

Private Holdings – GDRC and HRC

The GDRC dominates timber holdings north of Eureka while HRC has extensive holdings around Eureka and south.   Both these companies provide detailed publicly available management plans and holdings maps. Most of their holdings are managed second growth but they do have some old growth forests. Any old growth areas of three acres or more are voluntarily and permanently protected from harvesting and road construction by both of these companies.

I am not familiar with the access requirements for these areas but certainly written permission would be required from the respective company.

 

Headwaters Reserve

Some folks call this the “mysterious Headwaters Reserve”.   It was the scene of some famous forest protection protests in the 1990’s and culminated in 1999 with a $380 million purchase of 7,000 acres from the owning lumber company, of which 3,000 acres are old growth redwoods. The purchase was 100% taxpayer funded, $250 million from the Federal government and $130 million from the state of California. The Reserve is managed by the Bureau of Land Management.

The Reserve does have public access though it is limited.   There is a north approach which requires a five mile hike or bike from a parking area to reach the heart of the reserve.   Then there is a south approach from near Fortuna that requires a reservation and meeting up with a representative of the reserve.

This reserve contains a few redwoods in the 360 feet height range. This is exceptionally tall, there are less than sixty redwoods throughout their range that are over 360 feet in height. Undoubtedly there are exceptionally large diameter and volume trees in this reserve as well.

Headwaters Reserve low elevation north section (close in Google Earth view)
Headwaters Reserve low elevation north section (close in Google Earth view)

 

3      Record Breaking Redwoods Outside the Redwood State and National Parks?

 

Any of the lesser known areas highlighted above could hold a record breaking tall redwood tree. It is not likely but there is a chance. As one well known redwood explorer writes – “chance has potential”.

Based on the existing information on tallest redwoods, a super tall redwood can grow anywhere from near sea level to around 900 feet in elevation.   That covers a lot of ground. As long as the soil is good, there is some protection from wind from surrounding trees and hills, and there are year round water sources (nearby creeks, springs, and fog drip) a very tall redwood is a possibility.

Then to increase the possibility there needs to be a forest of trees growing in conditions for super tall redwoods. Each of the lesser known areas outlined above contains such a forest, as confirmed by the NASA global canopy height map.

For the same reasons there could also be very large (over 20,000 cubic feet) redwoods in these areas as well.

Thanks for reading.

 

 

 

Distribution of Tree Height in an Old Growth Redwood Forest

1      Old Growth Redwoods

 

Old growth redwoods – that phrase invokes a lot of different feelings in people. Certainly in the present the phrase describes the large never cut forests in the redwood parks. Forests full of giant trees, some by rivers or streams and others along hillsides. Forests covered with needles and sorrel and forests covered with ferns. Forests with deer moving through them to reach the creeks, all the while shadowed by mountain lions. Forests with black bear dens. Remote and rugged but never more than a few miles from a highway.

Two parks with many acres of old growth redwoods as well as the ten tallest trees in the world are Humboldt Redwoods State Park and Redwood National Park.   Each parks contains hundreds of thousands of old growth redwood trees.   Here is the math:

Park Acres Old Growth Redwoods # Redwood Trees > 100 cm per Hectare # Acres per Hectare # Old Growth Redwood Trees
HRSP                    17,000 50 2.47                            344,130
RNP                    19,640 50 2.47                            397,571

 

The redwood density figure is a general rounding of the findings in a redwood plots study underway at Humboldt State University.

If that number seems too high, well…. Here are two pictures.   These are from the Redwood Creek Overlook on Bald Hills Road in Redwood National Park.   The old growth forests and patches are very distinctive.   If you go to that overlook and put a strong pair of binoculars on those forests it is an impressive site.   Many big and tall trees all growing along Redwood Creek and the surrounding feeder creeks and hillsides. I can’t imagine a more spectacular forest. It is kind of intimidating.

Redwood Creek Overlook looking west northwest.
Redwood Creek Overlook looking west northwest.

 

Redwood Creek Overlook west southwest view
Redwood Creek Overlook west southwest view

 

2      Height Distribution for the Tallest Trees

 

Thorough ground based searches combined with LiDAR technology have given a pretty complete picture of tree height in all parks with the exception of the Headwaters Reserve. The tallest redwoods, those over 365 feet, are all in Humboldt Redwoods State Park and Redwood National Park, with the exception of two trees in the exceptional Montgomery Woods Reserve. Then all the trees over 370 feet (there are only ten or so) are in Humboldt Redwoods State Park and Redwood National Park.

 

Trees over 350 feet.  Each line represents a tree.
Trees over 350 feet. Each line represents a tree.

 

There are two things that are apparent when viewing these graphs. First, the distribution patterns are very similar between the parks. And second, there are a lot more tall trees in HRSP than in RNP. Based on this data paired with the history of each park the explanation is certainly this: In Humboldt most of the forests with the tallest trees are intact. In Redwood National Park most of the forests with the tallest trees have been thinned or removed.

 

3      Height Distribution for Old Growth Redwood Trees

 

Noting the steepness of the curve on the tall trees graph it is evident there is some type of “bell shaped” distribution where there are many trees of a certain height, say 350 feet, then the trees get fewer and fewer at 360 feet and even more scarce at 370 feet.

Using this information and the total number of old growth redwoods we can infer the number of trees of certain heights:

Std Deviations Expected Pct of Trees Less Than HRSP Expected Trees RNP Expected Trees HRSP + RNP Expected Trees
2 97.725%                      7,829                      9,045                              16,874
3 99.865%                          465                          537                                1,001
4 99.997%                            11                            13                                      23
4.5 99.99966%                              1                              1                                        3
5 99.99997% 0.0981 0.1133 0.21

Looking at the results of expected trees versus actual tree populations, it is evident four standard deviations describes 368 feet or so redwoods, while 4.5 standard deviations describes the very tallest redwoods (380 feet).

Then with some calculations and interpolation, we can arrive at three standard deviations corresponding to a 338 foot redwood tree.   This then results with the following very approximate distribution of tree height in old growth redwood forests in Humboldt Redwoods State Park and Redwood National Park.

Std Dev Height Feet
4.5 383
4 368
3 338
2 308
1 278
0 248
-1 218
-2 188
-3 158
-4 128
-4.5 113

 

So the average old growth redwood in Humboldt and Redwood NP is 250 feet tall.  Remember this covers all old growth trees at all elevations that are at least 3.28 feet in diameter.

Then there are 1,000 trees over 338 feet in height.

What do you think?

 

4      Old Growth Redwood Groves Close Ups

 

For some closer in views of old growth, here are pictures from two of my favorite areas in the redwood parks.   There are views like this all over the redwood parks.

 

Humboldt Bull Creek outflow
Humboldt Bull Creek outflow

 

Redwood NP Lost Man Creek area
Redwood NP Lost Man Creek area

 

Thanks for viewing and reading.